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Add Java and Python code for the following imgproc tutorials: Affine Transformations, Histogram Equalization, Histogram Calculation, Histogram Comparison, Back Projection.

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doc/tutorials/imgproc/histograms/back_projection/back_projection.markdown
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@ -67,46 +67,104 @@ Code
- Calculate the histogram (and update it if the bins change) and the backprojection of the - Calculate the histogram (and update it if the bins change) and the backprojection of the
same image. same image.
- Display the backprojection and the histogram in windows. - Display the backprojection and the histogram in windows.
- **Downloadable code**:
-# Click @add_toggle_cpp
- **Downloadable code**:
- Click
[here](https://github.com/opencv/opencv/tree/master/samples/cpp/tutorial_code/Histograms_Matching/calcBackProject_Demo1.cpp) [here](https://github.com/opencv/opencv/tree/master/samples/cpp/tutorial_code/Histograms_Matching/calcBackProject_Demo1.cpp)
for the basic version (explained in this tutorial). for the basic version (explained in this tutorial).
-# For stuff slightly fancier (using H-S histograms and floodFill to define a mask for the - For stuff slightly fancier (using H-S histograms and floodFill to define a mask for the
skin area) you can check the [improved skin area) you can check the [improved
demo](https://github.com/opencv/opencv/tree/master/samples/cpp/tutorial_code/Histograms_Matching/calcBackProject_Demo2.cpp) demo](https://github.com/opencv/opencv/tree/master/samples/cpp/tutorial_code/Histograms_Matching/calcBackProject_Demo2.cpp)
-# ...or you can always check out the classical - ...or you can always check out the classical
[camshiftdemo](https://github.com/opencv/opencv/tree/master/samples/cpp/camshiftdemo.cpp) [camshiftdemo](https://github.com/opencv/opencv/tree/master/samples/cpp/camshiftdemo.cpp)
in samples. in samples.
- **Code at glance:** - **Code at glance:**
@include samples/cpp/tutorial_code/Histograms_Matching/calcBackProject_Demo1.cpp @include samples/cpp/tutorial_code/Histograms_Matching/calcBackProject_Demo1.cpp
@end_toggle
@add_toggle_java
- **Downloadable code**:
- Click
[here](https://github.com/opencv/opencv/tree/master/samples/java/tutorial_code/Histograms_Matching/back_projection/CalcBackProjectDemo1.java)
for the basic version (explained in this tutorial).
- For stuff slightly fancier (using H-S histograms and floodFill to define a mask for the
skin area) you can check the [improved
demo](https://github.com/opencv/opencv/tree/master/samples/java/tutorial_code/Histograms_Matching/back_projection/CalcBackProjectDemo2.java)
- ...or you can always check out the classical
[camshiftdemo](https://github.com/opencv/opencv/tree/master/samples/cpp/camshiftdemo.cpp)
in samples.
- **Code at glance:**
@include samples/java/tutorial_code/Histograms_Matching/back_projection/CalcBackProjectDemo1.java
@end_toggle
@add_toggle_python
- **Downloadable code**:
- Click
[here](https://github.com/opencv/opencv/tree/master/samples/python/tutorial_code/Histograms_Matching/back_projection/calcBackProject_Demo1.py)
for the basic version (explained in this tutorial).
- For stuff slightly fancier (using H-S histograms and floodFill to define a mask for the
skin area) you can check the [improved
demo](https://github.com/opencv/opencv/tree/master/samples/python/tutorial_code/Histograms_Matching/back_projection/calcBackProject_Demo2.py)
- ...or you can always check out the classical
[camshiftdemo](https://github.com/opencv/opencv/tree/master/samples/cpp/camshiftdemo.cpp)
in samples.
- **Code at glance:**
@include samples/python/tutorial_code/Histograms_Matching/back_projection/calcBackProject_Demo1.py
@end_toggle
Explanation Explanation
----------- -----------
-# Declare the matrices to store our images and initialize the number of bins to be used by our - Read the input image:
histogram:
@code{.cpp} @add_toggle_cpp
Mat src; Mat hsv; Mat hue; @snippet samples/cpp/tutorial_code/Histograms_Matching/calcBackProject_Demo1.cpp Read the image
int bins = 25; @end_toggle
@endcode
-# Read the input image and transform it to HSV format: @add_toggle_java
@code{.cpp} @snippet samples/java/tutorial_code/Histograms_Matching/back_projection/CalcBackProjectDemo1.java Read the image
src = imread( argv[1], 1 ); @end_toggle
cvtColor( src, hsv, COLOR_BGR2HSV );
@endcode @add_toggle_python
-# For this tutorial, we will use only the Hue value for our 1-D histogram (check out the fancier @snippet samples/python/tutorial_code/Histograms_Matching/back_projection/calcBackProject_Demo1.py Read the image
@end_toggle
- Transform it to HSV format:
@add_toggle_cpp
@snippet samples/cpp/tutorial_code/Histograms_Matching/calcBackProject_Demo1.cpp Transform it to HSV
@end_toggle
@add_toggle_java
@snippet samples/java/tutorial_code/Histograms_Matching/back_projection/CalcBackProjectDemo1.java Transform it to HSV
@end_toggle
@add_toggle_python
@snippet samples/python/tutorial_code/Histograms_Matching/back_projection/calcBackProject_Demo1.py Transform it to HSV
@end_toggle
- For this tutorial, we will use only the Hue value for our 1-D histogram (check out the fancier
code in the links above if you want to use the more standard H-S histogram, which yields better code in the links above if you want to use the more standard H-S histogram, which yields better
results): results):
@code{.cpp}
hue.create( hsv.size(), hsv.depth() );
int ch[] = { 0, 0 };
mixChannels( &hsv, 1, &hue, 1, ch, 1 );
@endcode
as you see, we use the function @ref cv::mixChannels to get only the channel 0 (Hue) from
the hsv image. It gets the following parameters:
@add_toggle_cpp
@snippet samples/cpp/tutorial_code/Histograms_Matching/calcBackProject_Demo1.cpp Use only the Hue value
@end_toggle
@add_toggle_java
@snippet samples/java/tutorial_code/Histograms_Matching/back_projection/CalcBackProjectDemo1.java Use only the Hue value
@end_toggle
@add_toggle_python
@snippet samples/python/tutorial_code/Histograms_Matching/back_projection/calcBackProject_Demo1.py Use only the Hue value
@end_toggle
- as you see, we use the function @ref cv::mixChannels to get only the channel 0 (Hue) from
the hsv image. It gets the following parameters:
- **&hsv:** The source array from which the channels will be copied - **&hsv:** The source array from which the channels will be copied
- **1:** The number of source arrays - **1:** The number of source arrays
- **&hue:** The destination array of the copied channels - **&hue:** The destination array of the copied channels
@ -115,59 +173,108 @@ Explanation
case, the Hue(0) channel of &hsv is being copied to the 0 channel of &hue (1-channel) case, the Hue(0) channel of &hsv is being copied to the 0 channel of &hue (1-channel)
- **1:** Number of index pairs - **1:** Number of index pairs
-# Create a Trackbar for the user to enter the bin values. Any change on the Trackbar means a call - Create a Trackbar for the user to enter the bin values. Any change on the Trackbar means a call
to the **Hist_and_Backproj** callback function. to the **Hist_and_Backproj** callback function.
@code{.cpp}
char* window_image = "Source image";
namedWindow( window_image, WINDOW_AUTOSIZE );
createTrackbar("* Hue bins: ", window_image, &bins, 180, Hist_and_Backproj );
Hist_and_Backproj(0, 0);
@endcode
-# Show the image and wait for the user to exit the program:
@code{.cpp}
imshow( window_image, src );
waitKey(0); @add_toggle_cpp
return 0; @snippet samples/cpp/tutorial_code/Histograms_Matching/calcBackProject_Demo1.cpp Create Trackbar to enter the number of bins
@endcode @end_toggle
-# **Hist_and_Backproj function:** Initialize the arguments needed for @ref cv::calcHist . The
@add_toggle_java
@snippet samples/java/tutorial_code/Histograms_Matching/back_projection/CalcBackProjectDemo1.java Create Trackbar to enter the number of bins
@end_toggle
@add_toggle_python
@snippet samples/python/tutorial_code/Histograms_Matching/back_projection/calcBackProject_Demo1.py Create Trackbar to enter the number of bins
@end_toggle
- Show the image and wait for the user to exit the program:
@add_toggle_cpp
@snippet samples/cpp/tutorial_code/Histograms_Matching/calcBackProject_Demo1.cpp Show the image
@end_toggle
@add_toggle_java
@snippet samples/java/tutorial_code/Histograms_Matching/back_projection/CalcBackProjectDemo1.java Show the image
@end_toggle
@add_toggle_python
@snippet samples/python/tutorial_code/Histograms_Matching/back_projection/calcBackProject_Demo1.py Show the image
@end_toggle
- **Hist_and_Backproj function:** Initialize the arguments needed for @ref cv::calcHist . The
number of bins comes from the Trackbar: number of bins comes from the Trackbar:
@code{.cpp}
void Hist_and_Backproj(int, void* ) @add_toggle_cpp
{ @snippet samples/cpp/tutorial_code/Histograms_Matching/calcBackProject_Demo1.cpp initialize
MatND hist; @end_toggle
int histSize = MAX( bins, 2 );
float hue_range[] = { 0, 180 }; @add_toggle_java
const float* ranges = { hue_range }; @snippet samples/java/tutorial_code/Histograms_Matching/back_projection/CalcBackProjectDemo1.java initialize
@endcode @end_toggle
-# Calculate the Histogram and normalize it to the range \f$[0,255]\f$
@code{.cpp} @add_toggle_python
calcHist( &hue, 1, 0, Mat(), hist, 1, &histSize, &ranges, true, false ); @snippet samples/python/tutorial_code/Histograms_Matching/back_projection/calcBackProject_Demo1.py initialize
normalize( hist, hist, 0, 255, NORM_MINMAX, -1, Mat() ); @end_toggle
@endcode
-# Get the Backprojection of the same image by calling the function @ref cv::calcBackProject - Calculate the Histogram and normalize it to the range \f$[0,255]\f$
@code{.cpp}
MatND backproj; @add_toggle_cpp
calcBackProject( &hue, 1, 0, hist, backproj, &ranges, 1, true ); @snippet samples/cpp/tutorial_code/Histograms_Matching/calcBackProject_Demo1.cpp Get the Histogram and normalize it
@endcode @end_toggle
all the arguments are known (the same as used to calculate the histogram), only we add the
@add_toggle_java
@snippet samples/java/tutorial_code/Histograms_Matching/back_projection/CalcBackProjectDemo1.java Get the Histogram and normalize it
@end_toggle
@add_toggle_python
@snippet samples/python/tutorial_code/Histograms_Matching/back_projection/calcBackProject_Demo1.py Get the Histogram and normalize it
@end_toggle
- Get the Backprojection of the same image by calling the function @ref cv::calcBackProject
@add_toggle_cpp
@snippet samples/cpp/tutorial_code/Histograms_Matching/calcBackProject_Demo1.cpp Get Backprojection
@end_toggle
@add_toggle_java
@snippet samples/java/tutorial_code/Histograms_Matching/back_projection/CalcBackProjectDemo1.java Get Backprojection
@end_toggle
@add_toggle_python
@snippet samples/python/tutorial_code/Histograms_Matching/back_projection/calcBackProject_Demo1.py Get Backprojection
@end_toggle
- all the arguments are known (the same as used to calculate the histogram), only we add the
backproj matrix, which will store the backprojection of the source image (&hue) backproj matrix, which will store the backprojection of the source image (&hue)
-# Display backproj: - Display backproj:
@code{.cpp}
imshow( "BackProj", backproj );
@endcode
-# Draw the 1-D Hue histogram of the image:
@code{.cpp}
int w = 400; int h = 400;
int bin_w = cvRound( (double) w / histSize );
Mat histImg = Mat::zeros( w, h, CV_8UC3 );
for( int i = 0; i < bins; i ++ ) @add_toggle_cpp
{ rectangle( histImg, Point( i*bin_w, h ), Point( (i+1)*bin_w, h - cvRound( hist.at<float>(i)*h/255.0 ) ), Scalar( 0, 0, 255 ), -1 ); } @snippet samples/cpp/tutorial_code/Histograms_Matching/calcBackProject_Demo1.cpp Draw the backproj
@end_toggle
imshow( "Histogram", histImg ); @add_toggle_java
@endcode @snippet samples/java/tutorial_code/Histograms_Matching/back_projection/CalcBackProjectDemo1.java Draw the backproj
@end_toggle
@add_toggle_python
@snippet samples/python/tutorial_code/Histograms_Matching/back_projection/calcBackProject_Demo1.py Draw the backproj
@end_toggle
- Draw the 1-D Hue histogram of the image:
@add_toggle_cpp
@snippet samples/cpp/tutorial_code/Histograms_Matching/calcBackProject_Demo1.cpp Draw the histogram
@end_toggle
@add_toggle_java
@snippet samples/java/tutorial_code/Histograms_Matching/back_projection/CalcBackProjectDemo1.java Draw the histogram
@end_toggle
@add_toggle_python
@snippet samples/python/tutorial_code/Histograms_Matching/back_projection/calcBackProject_Demo1.py Draw the histogram
@end_toggle
Results Results
------- -------

274
doc/tutorials/imgproc/histograms/histogram_calculation/histogram_calculation.markdown
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@ -17,7 +17,8 @@ histogram called *Image histogram*. Now we will considerate it in its more gener
- Histograms are collected *counts* of data organized into a set of predefined *bins* - Histograms are collected *counts* of data organized into a set of predefined *bins*
- When we say *data* we are not restricting it to be intensity values (as we saw in the previous - When we say *data* we are not restricting it to be intensity values (as we saw in the previous
Tutorial). The data collected can be whatever feature you find useful to describe your image. Tutorial @ref tutorial_histogram_equalization). The data collected can be whatever feature you find
useful to describe your image.
- Let's see an example. Imagine that a Matrix contains information of an image (i.e. intensity in - Let's see an example. Imagine that a Matrix contains information of an image (i.e. intensity in
the range \f$0-255\f$): the range \f$0-255\f$):
@ -65,122 +66,193 @@ Code
- Splits the image into its R, G and B planes using the function @ref cv::split - Splits the image into its R, G and B planes using the function @ref cv::split
- Calculate the Histogram of each 1-channel plane by calling the function @ref cv::calcHist - Calculate the Histogram of each 1-channel plane by calling the function @ref cv::calcHist
- Plot the three histograms in a window - Plot the three histograms in a window
@add_toggle_cpp
- **Downloadable code**: Click - **Downloadable code**: Click
[here](https://github.com/opencv/opencv/tree/master/samples/cpp/tutorial_code/Histograms_Matching/calcHist_Demo.cpp) [here](https://github.com/opencv/opencv/tree/master/samples/cpp/tutorial_code/Histograms_Matching/calcHist_Demo.cpp)
- **Code at glance:** - **Code at glance:**
@include samples/cpp/tutorial_code/Histograms_Matching/calcHist_Demo.cpp @include samples/cpp/tutorial_code/Histograms_Matching/calcHist_Demo.cpp
@end_toggle
@add_toggle_java
- **Downloadable code**: Click
[here](https://github.com/opencv/opencv/tree/master/samples/java/tutorial_code/Histograms_Matching/histogram_calculation/CalcHistDemo.java)
- **Code at glance:**
@include samples/java/tutorial_code/Histograms_Matching/histogram_calculation/CalcHistDemo.java
@end_toggle
@add_toggle_python
- **Downloadable code**: Click
[here](https://github.com/opencv/opencv/tree/master/samples/python/tutorial_code/Histograms_Matching/histogram_calculation/calcHist_Demo.py)
- **Code at glance:**
@include samples/python/tutorial_code/Histograms_Matching/histogram_calculation/calcHist_Demo.py
@end_toggle
Explanation Explanation
----------- -----------
-# Create the necessary matrices: - Load the source image
@code{.cpp}
Mat src, dst;
@endcode
-# Load the source image
@code{.cpp}
src = imread( argv[1], 1 );
if( !src.data ) @add_toggle_cpp
{ return -1; } @snippet samples/cpp/tutorial_code/Histograms_Matching/calcHist_Demo.cpp Load image
@endcode @end_toggle
-# Separate the source image in its three R,G and B planes. For this we use the OpenCV function
@add_toggle_java
@snippet samples/java/tutorial_code/Histograms_Matching/histogram_calculation/CalcHistDemo.java Load image
@end_toggle
@add_toggle_python
@snippet samples/python/tutorial_code/Histograms_Matching/histogram_calculation/calcHist_Demo.py Load image
@end_toggle
- Separate the source image in its three R,G and B planes. For this we use the OpenCV function
@ref cv::split : @ref cv::split :
@code{.cpp}
vector<Mat> bgr_planes; @add_toggle_cpp
split( src, bgr_planes ); @snippet samples/cpp/tutorial_code/Histograms_Matching/calcHist_Demo.cpp Separate the image in 3 places ( B, G and R )
@endcode @end_toggle
@add_toggle_java
@snippet samples/java/tutorial_code/Histograms_Matching/histogram_calculation/CalcHistDemo.java Separate the image in 3 places ( B, G and R )
@end_toggle
@add_toggle_python
@snippet samples/python/tutorial_code/Histograms_Matching/histogram_calculation/calcHist_Demo.py Separate the image in 3 places ( B, G and R )
@end_toggle
our input is the image to be divided (this case with three channels) and the output is a vector our input is the image to be divided (this case with three channels) and the output is a vector
of Mat ) of Mat )
-# Now we are ready to start configuring the **histograms** for each plane. Since we are working - Now we are ready to start configuring the **histograms** for each plane. Since we are working
with the B, G and R planes, we know that our values will range in the interval \f$[0,255]\f$ with the B, G and R planes, we know that our values will range in the interval \f$[0,255]\f$
-# Establish number of bins (5, 10...):
@code{.cpp}
int histSize = 256; //from 0 to 255
@endcode
-# Set the range of values (as we said, between 0 and 255 )
@code{.cpp}
/// Set the ranges ( for B,G,R) )
float range[] = { 0, 256 } ; //the upper boundary is exclusive
const float* histRange = { range };
@endcode
-# We want our bins to have the same size (uniform) and to clear the histograms in the
beginning, so:
@code{.cpp}
bool uniform = true; bool accumulate = false;
@endcode
-# Finally, we create the Mat objects to save our histograms. Creating 3 (one for each plane):
@code{.cpp}
Mat b_hist, g_hist, r_hist;
@endcode
-# We proceed to calculate the histograms by using the OpenCV function @ref cv::calcHist :
@code{.cpp}
/// Compute the histograms:
calcHist( &bgr_planes[0], 1, 0, Mat(), b_hist, 1, &histSize, &histRange, uniform, accumulate );
calcHist( &bgr_planes[1], 1, 0, Mat(), g_hist, 1, &histSize, &histRange, uniform, accumulate );
calcHist( &bgr_planes[2], 1, 0, Mat(), r_hist, 1, &histSize, &histRange, uniform, accumulate );
@endcode
where the arguments are:
- **&bgr_planes[0]:** The source array(s) - Establish the number of bins (5, 10...):
- **1**: The number of source arrays (in this case we are using 1. We can enter here also
a list of arrays )
- **0**: The channel (*dim*) to be measured. In this case it is just the intensity (each
array is single-channel) so we just write 0.
- **Mat()**: A mask to be used on the source array ( zeros indicating pixels to be ignored
). If not defined it is not used
- **b_hist**: The Mat object where the histogram will be stored
- **1**: The histogram dimensionality.
- **histSize:** The number of bins per each used dimension
- **histRange:** The range of values to be measured per each dimension
- **uniform** and **accumulate**: The bin sizes are the same and the histogram is cleared
at the beginning.
-# Create an image to display the histograms: @add_toggle_cpp
@code{.cpp} @snippet samples/cpp/tutorial_code/Histograms_Matching/calcHist_Demo.cpp Establish the number of bins
// Draw the histograms for R, G and B @end_toggle
int hist_w = 512; int hist_h = 400;
int bin_w = cvRound( (double) hist_w/histSize );
Mat histImage( hist_h, hist_w, CV_8UC3, Scalar( 0,0,0) ); @add_toggle_java
@endcode @snippet samples/java/tutorial_code/Histograms_Matching/histogram_calculation/CalcHistDemo.java Establish the number of bins
-# Notice that before drawing, we first @ref cv::normalize the histogram so its values fall in the @end_toggle
@add_toggle_python
@snippet samples/python/tutorial_code/Histograms_Matching/histogram_calculation/calcHist_Demo.py Establish the number of bins
@end_toggle
- Set the range of values (as we said, between 0 and 255 )
@add_toggle_cpp
@snippet samples/cpp/tutorial_code/Histograms_Matching/calcHist_Demo.cpp Set the ranges ( for B,G,R) )
@end_toggle
@add_toggle_java
@snippet samples/java/tutorial_code/Histograms_Matching/histogram_calculation/CalcHistDemo.java Set the ranges ( for B,G,R) )
@end_toggle
@add_toggle_python
@snippet samples/python/tutorial_code/Histograms_Matching/histogram_calculation/calcHist_Demo.py Set the ranges ( for B,G,R) )
@end_toggle
- We want our bins to have the same size (uniform) and to clear the histograms in the
beginning, so:
@add_toggle_cpp
@snippet samples/cpp/tutorial_code/Histograms_Matching/calcHist_Demo.cpp Set histogram param
@end_toggle
@add_toggle_java
@snippet samples/java/tutorial_code/Histograms_Matching/histogram_calculation/CalcHistDemo.java Set histogram param
@end_toggle
@add_toggle_python
@snippet samples/python/tutorial_code/Histograms_Matching/histogram_calculation/calcHist_Demo.py Set histogram param
@end_toggle
- We proceed to calculate the histograms by using the OpenCV function @ref cv::calcHist :
@add_toggle_cpp
@snippet samples/cpp/tutorial_code/Histograms_Matching/calcHist_Demo.cpp Compute the histograms
@end_toggle
@add_toggle_java
@snippet samples/java/tutorial_code/Histograms_Matching/histogram_calculation/CalcHistDemo.java Compute the histograms
@end_toggle
@add_toggle_python
@snippet samples/python/tutorial_code/Histograms_Matching/histogram_calculation/calcHist_Demo.py Compute the histograms
@end_toggle
- where the arguments are (**C++ code**):
- **&bgr_planes[0]:** The source array(s)
- **1**: The number of source arrays (in this case we are using 1. We can enter here also
a list of arrays )
- **0**: The channel (*dim*) to be measured. In this case it is just the intensity (each
array is single-channel) so we just write 0.
- **Mat()**: A mask to be used on the source array ( zeros indicating pixels to be ignored
). If not defined it is not used
- **b_hist**: The Mat object where the histogram will be stored
- **1**: The histogram dimensionality.
- **histSize:** The number of bins per each used dimension
- **histRange:** The range of values to be measured per each dimension
- **uniform** and **accumulate**: The bin sizes are the same and the histogram is cleared
at the beginning.
- Create an image to display the histograms:
@add_toggle_cpp
@snippet samples/cpp/tutorial_code/Histograms_Matching/calcHist_Demo.cpp Draw the histograms for B, G and R
@end_toggle
@add_toggle_java
@snippet samples/java/tutorial_code/Histograms_Matching/histogram_calculation/CalcHistDemo.java Draw the histograms for B, G and R
@end_toggle
@add_toggle_python
@snippet samples/python/tutorial_code/Histograms_Matching/histogram_calculation/calcHist_Demo.py Draw the histograms for B, G and R
@end_toggle
- Notice that before drawing, we first @ref cv::normalize the histogram so its values fall in the
range indicated by the parameters entered: range indicated by the parameters entered:
@code{.cpp}
/// Normalize the result to [ 0, histImage.rows ]
normalize(b_hist, b_hist, 0, histImage.rows, NORM_MINMAX, -1, Mat() );
normalize(g_hist, g_hist, 0, histImage.rows, NORM_MINMAX, -1, Mat() );
normalize(r_hist, r_hist, 0, histImage.rows, NORM_MINMAX, -1, Mat() );
@endcode
this function receives these arguments:
@add_toggle_cpp
@snippet samples/cpp/tutorial_code/Histograms_Matching/calcHist_Demo.cpp Normalize the result to ( 0, histImage.rows )
@end_toggle
@add_toggle_java
@snippet samples/java/tutorial_code/Histograms_Matching/histogram_calculation/CalcHistDemo.java Normalize the result to ( 0, histImage.rows )
@end_toggle
@add_toggle_python
@snippet samples/python/tutorial_code/Histograms_Matching/histogram_calculation/calcHist_Demo.py Normalize the result to ( 0, histImage.rows )
@end_toggle
- this function receives these arguments (**C++ code**):
- **b_hist:** Input array - **b_hist:** Input array
- **b_hist:** Output normalized array (can be the same) - **b_hist:** Output normalized array (can be the same)
- **0** and\**histImage.rows: For this example, they are the lower and upper limits to - **0** and **histImage.rows**: For this example, they are the lower and upper limits to
normalize the values ofr_hist*\* normalize the values of **r_hist**
- **NORM_MINMAX:** Argument that indicates the type of normalization (as described above, it - **NORM_MINMAX:** Argument that indicates the type of normalization (as described above, it
adjusts the values between the two limits set before) adjusts the values between the two limits set before)
- **-1:** Implies that the output normalized array will be the same type as the input - **-1:** Implies that the output normalized array will be the same type as the input
- **Mat():** Optional mask - **Mat():** Optional mask
-# Finally, observe that to access the bin (in this case in this 1D-Histogram): - Observe that to access the bin (in this case in this 1D-Histogram):
@code{.cpp}
/// Draw for each channel @add_toggle_cpp
for( int i = 1; i < histSize; i++ ) @snippet samples/cpp/tutorial_code/Histograms_Matching/calcHist_Demo.cpp Draw for each channel
{ @end_toggle
line( histImage, Point( bin_w*(i-1), hist_h - cvRound(b_hist.at<float>(i-1)) ) ,
Point( bin_w*(i), hist_h - cvRound(b_hist.at<float>(i)) ), @add_toggle_java
Scalar( 255, 0, 0), 2, 8, 0 ); @snippet samples/java/tutorial_code/Histograms_Matching/histogram_calculation/CalcHistDemo.java Draw for each channel
line( histImage, Point( bin_w*(i-1), hist_h - cvRound(g_hist.at<float>(i-1)) ) , @end_toggle
Point( bin_w*(i), hist_h - cvRound(g_hist.at<float>(i)) ),
Scalar( 0, 255, 0), 2, 8, 0 ); @add_toggle_python
line( histImage, Point( bin_w*(i-1), hist_h - cvRound(r_hist.at<float>(i-1)) ) , @snippet samples/python/tutorial_code/Histograms_Matching/histogram_calculation/calcHist_Demo.py Draw for each channel
Point( bin_w*(i), hist_h - cvRound(r_hist.at<float>(i)) ), @end_toggle
Scalar( 0, 0, 255), 2, 8, 0 ); we use the expression (**C++ code**):
}
@endcode
we use the expression:
@code{.cpp} @code{.cpp}
b_hist.at<float>(i) b_hist.at<float>(i)
@endcode @endcode
@ -189,20 +261,24 @@ Explanation
b_hist.at<float>( i, j ) b_hist.at<float>( i, j )
@endcode @endcode
-# Finally we display our histograms and wait for the user to exit: - Finally we display our histograms and wait for the user to exit:
@code{.cpp}
namedWindow("calcHist Demo", WINDOW_AUTOSIZE );
imshow("calcHist Demo", histImage );
waitKey(0); @add_toggle_cpp
@snippet samples/cpp/tutorial_code/Histograms_Matching/calcHist_Demo.cpp Display
@end_toggle
return 0; @add_toggle_java
@endcode @snippet samples/java/tutorial_code/Histograms_Matching/histogram_calculation/CalcHistDemo.java Display
@end_toggle
@add_toggle_python
@snippet samples/python/tutorial_code/Histograms_Matching/histogram_calculation/calcHist_Demo.py Display
@end_toggle
Result Result
------ ------
-# Using as input argument an image like the shown below: -# Using as input argument an image like the one shown below:
![](images/Histogram_Calculation_Original_Image.jpg) ![](images/Histogram_Calculation_Original_Image.jpg)

174
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View File

@ -43,90 +43,118 @@ Code
- Compare the histogram of the *base image* with respect to the 2 test histograms, the - Compare the histogram of the *base image* with respect to the 2 test histograms, the
histogram of the lower half base image and with the same base image histogram. histogram of the lower half base image and with the same base image histogram.
- Display the numerical matching parameters obtained. - Display the numerical matching parameters obtained.
@add_toggle_cpp
- **Downloadable code**: Click - **Downloadable code**: Click
[here](https://github.com/opencv/opencv/tree/master/samples/cpp/tutorial_code/Histograms_Matching/compareHist_Demo.cpp) [here](https://github.com/opencv/opencv/tree/master/samples/cpp/tutorial_code/Histograms_Matching/compareHist_Demo.cpp)
- **Code at glance:**
@include cpp/tutorial_code/Histograms_Matching/compareHist_Demo.cpp - **Code at glance:**
@include samples/cpp/tutorial_code/Histograms_Matching/compareHist_Demo.cpp
@end_toggle
@add_toggle_java
- **Downloadable code**: Click
[here](https://github.com/opencv/opencv/tree/master/samples/java/tutorial_code/Histograms_Matching/histogram_comparison/CompareHistDemo.java)
- **Code at glance:**
@include samples/java/tutorial_code/Histograms_Matching/histogram_comparison/CompareHistDemo.java
@end_toggle
@add_toggle_python
- **Downloadable code**: Click
[here](https://github.com/opencv/opencv/tree/master/samples/python/tutorial_code/Histograms_Matching/histogram_comparison/compareHist_Demo.py)
- **Code at glance:**
@include samples/python/tutorial_code/Histograms_Matching/histogram_comparison/compareHist_Demo.py
@end_toggle
Explanation Explanation
----------- -----------
-# Declare variables such as the matrices to store the base image and the two other images to - Load the base image (src_base) and the other two test images:
compare ( BGR and HSV )
@code{.cpp}
Mat src_base, hsv_base;
Mat src_test1, hsv_test1;
Mat src_test2, hsv_test2;
Mat hsv_half_down;
@endcode
-# Load the base image (src_base) and the other two test images:
@code{.cpp}
if( argc < 4 )
{ printf("** Error. Usage: ./compareHist_Demo <image_settings0> <image_setting1> <image_settings2>\n");
return -1;
}
src_base = imread( argv[1], 1 ); @add_toggle_cpp
src_test1 = imread( argv[2], 1 ); @snippet samples/cpp/tutorial_code/Histograms_Matching/compareHist_Demo.cpp Load three images with different environment settings
src_test2 = imread( argv[3], 1 ); @end_toggle
@endcode
-# Convert them to HSV format:
@code{.cpp}
cvtColor( src_base, hsv_base, COLOR_BGR2HSV );
cvtColor( src_test1, hsv_test1, COLOR_BGR2HSV );
cvtColor( src_test2, hsv_test2, COLOR_BGR2HSV );
@endcode
-# Also, create an image of half the base image (in HSV format):
@code{.cpp}
hsv_half_down = hsv_base( Range( hsv_base.rows/2, hsv_base.rows - 1 ), Range( 0, hsv_base.cols - 1 ) );
@endcode
-# Initialize the arguments to calculate the histograms (bins, ranges and channels H and S ).
@code{.cpp}
int h_bins = 50; int s_bins = 60;
int histSize[] = { h_bins, s_bins };
float h_ranges[] = { 0, 180 }; @add_toggle_java
float s_ranges[] = { 0, 256 }; @snippet samples/java/tutorial_code/Histograms_Matching/histogram_comparison/CompareHistDemo.java Load three images with different environment settings
@end_toggle
const float* ranges[] = { h_ranges, s_ranges }; @add_toggle_python
@snippet samples/python/tutorial_code/Histograms_Matching/histogram_comparison/compareHist_Demo.py Load three images with different environment settings
@end_toggle
int channels[] = { 0, 1 }; - Convert them to HSV format:
@endcode
-# Create the MatND objects to store the histograms:
@code{.cpp}
MatND hist_base;
MatND hist_half_down;
MatND hist_test1;
MatND hist_test2;
@endcode
-# Calculate the Histograms for the base image, the 2 test images and the half-down base image:
@code{.cpp}
calcHist( &hsv_base, 1, channels, Mat(), hist_base, 2, histSize, ranges, true, false );
normalize( hist_base, hist_base, 0, 1, NORM_MINMAX, -1, Mat() );
calcHist( &hsv_half_down, 1, channels, Mat(), hist_half_down, 2, histSize, ranges, true, false ); @add_toggle_cpp
normalize( hist_half_down, hist_half_down, 0, 1, NORM_MINMAX, -1, Mat() ); @snippet samples/cpp/tutorial_code/Histograms_Matching/compareHist_Demo.cpp Convert to HSV
@end_toggle
calcHist( &hsv_test1, 1, channels, Mat(), hist_test1, 2, histSize, ranges, true, false ); @add_toggle_java
normalize( hist_test1, hist_test1, 0, 1, NORM_MINMAX, -1, Mat() ); @snippet samples/java/tutorial_code/Histograms_Matching/histogram_comparison/CompareHistDemo.java Convert to HSV
@end_toggle
calcHist( &hsv_test2, 1, channels, Mat(), hist_test2, 2, histSize, ranges, true, false ); @add_toggle_python
normalize( hist_test2, hist_test2, 0, 1, NORM_MINMAX, -1, Mat() ); @snippet samples/python/tutorial_code/Histograms_Matching/histogram_comparison/compareHist_Demo.py Convert to HSV
@endcode @end_toggle
-# Apply sequentially the 4 comparison methods between the histogram of the base image (hist_base)
- Also, create an image of half the base image (in HSV format):
@add_toggle_cpp
@snippet samples/cpp/tutorial_code/Histograms_Matching/compareHist_Demo.cpp Convert to HSV half
@end_toggle
@add_toggle_java
@snippet samples/java/tutorial_code/Histograms_Matching/histogram_comparison/CompareHistDemo.java Convert to HSV half
@end_toggle
@add_toggle_python
@snippet samples/python/tutorial_code/Histograms_Matching/histogram_comparison/compareHist_Demo.py Convert to HSV half
@end_toggle
- Initialize the arguments to calculate the histograms (bins, ranges and channels H and S ).
@add_toggle_cpp
@snippet samples/cpp/tutorial_code/Histograms_Matching/compareHist_Demo.cpp Using 50 bins for hue and 60 for saturation
@end_toggle
@add_toggle_java
@snippet samples/java/tutorial_code/Histograms_Matching/histogram_comparison/CompareHistDemo.java Using 50 bins for hue and 60 for saturation
@end_toggle
@add_toggle_python
@snippet samples/python/tutorial_code/Histograms_Matching/histogram_comparison/compareHist_Demo.py Using 50 bins for hue and 60 for saturation
@end_toggle
- Calculate the Histograms for the base image, the 2 test images and the half-down base image:
@add_toggle_cpp
@snippet samples/cpp/tutorial_code/Histograms_Matching/compareHist_Demo.cpp Calculate the histograms for the HSV images
@end_toggle
@add_toggle_java
@snippet samples/java/tutorial_code/Histograms_Matching/histogram_comparison/CompareHistDemo.java Calculate the histograms for the HSV images
@end_toggle
@add_toggle_python
@snippet samples/python/tutorial_code/Histograms_Matching/histogram_comparison/compareHist_Demo.py Calculate the histograms for the HSV images
@end_toggle
- Apply sequentially the 4 comparison methods between the histogram of the base image (hist_base)
and the other histograms: and the other histograms:
@code{.cpp}
for( int i = 0; i < 4; i++ )
{ int compare_method = i;
double base_base = compareHist( hist_base, hist_base, compare_method );
double base_half = compareHist( hist_base, hist_half_down, compare_method );
double base_test1 = compareHist( hist_base, hist_test1, compare_method );
double base_test2 = compareHist( hist_base, hist_test2, compare_method );
printf( " Method [%d] Perfect, Base-Half, Base-Test(1), Base-Test(2) : %f, %f, %f, %f \n", i, base_base, base_half , base_test1, base_test2 ); @add_toggle_cpp
} @snippet samples/cpp/tutorial_code/Histograms_Matching/compareHist_Demo.cpp Apply the histogram comparison methods
@endcode @end_toggle
@add_toggle_java
@snippet samples/java/tutorial_code/Histograms_Matching/histogram_comparison/CompareHistDemo.java Apply the histogram comparison methods
@end_toggle
@add_toggle_python
@snippet samples/python/tutorial_code/Histograms_Matching/histogram_comparison/compareHist_Demo.py Apply the histogram comparison methods
@end_toggle
Results Results
------- -------
@ -144,13 +172,13 @@ Results
are from the same source. For the other two test images, we can observe that they have very are from the same source. For the other two test images, we can observe that they have very
different lighting conditions, so the matching should not be very good: different lighting conditions, so the matching should not be very good:
-# Here the numeric results: -# Here the numeric results we got with OpenCV 3.4.1:
*Method* | Base - Base | Base - Half | Base - Test 1 | Base - Test 2 *Method* | Base - Base | Base - Half | Base - Test 1 | Base - Test 2
----------------- | ------------ | ------------ | -------------- | --------------- ----------------- | ------------ | ------------ | -------------- | ---------------
*Correlation* | 1.000000 | 0.930766 | 0.182073 | 0.120447 *Correlation* | 1.000000 | 0.880438 | 0.20457 | 0.0664547
*Chi-square* | 0.000000 | 4.940466 | 21.184536 | 49.273437 *Chi-square* | 0.000000 | 4.6834 | 2697.98 | 4763.8
*Intersection* | 24.391548 | 14.959809 | 3.889029 | 5.775088 *Intersection* | 18.8947 | 13.022 | 5.44085 | 2.58173
*Bhattacharyya* | 0.000000 | 0.222609 | 0.646576 | 0.801869 *Bhattacharyya* | 0.000000 | 0.237887 | 0.679826 | 0.874173
For the *Correlation* and *Intersection* methods, the higher the metric, the more accurate the For the *Correlation* and *Intersection* methods, the higher the metric, the more accurate the
match. As we can see, the match *base-base* is the highest of all as expected. Also we can observe match. As we can see, the match *base-base* is the highest of all as expected. Also we can observe
that the match *base-half* is the second best match (as we predicted). For the other two metrics, that the match *base-half* is the second best match (as we predicted). For the other two metrics,

120
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@ -22,7 +22,7 @@ Theory
### What is Histogram Equalization? ### What is Histogram Equalization?
- It is a method that improves the contrast in an image, in order to stretch out the intensity - It is a method that improves the contrast in an image, in order to stretch out the intensity
range. range (see also the corresponding <a href="https://en.wikipedia.org/wiki/Histogram_equalization">Wikipedia entry</a>).
- To make it clearer, from the image above, you can see that the pixels seem clustered around the - To make it clearer, from the image above, you can see that the pixels seem clustered around the
middle of the available range of intensities. What Histogram Equalization does is to *stretch middle of the available range of intensities. What Histogram Equalization does is to *stretch
out* this range. Take a look at the figure below: The green circles indicate the out* this range. Take a look at the figure below: The green circles indicate the
@ -61,53 +61,105 @@ Code
- Convert the original image to grayscale - Convert the original image to grayscale
- Equalize the Histogram by using the OpenCV function @ref cv::equalizeHist - Equalize the Histogram by using the OpenCV function @ref cv::equalizeHist
- Display the source and equalized images in a window. - Display the source and equalized images in a window.
@add_toggle_cpp
- **Downloadable code**: Click - **Downloadable code**: Click
[here](https://github.com/opencv/opencv/tree/master/samples/cpp/tutorial_code/Histograms_Matching/EqualizeHist_Demo.cpp) [here](https://github.com/opencv/opencv/tree/master/samples/cpp/tutorial_code/Histograms_Matching/EqualizeHist_Demo.cpp)
- **Code at glance:** - **Code at glance:**
@include samples/cpp/tutorial_code/Histograms_Matching/EqualizeHist_Demo.cpp @include samples/cpp/tutorial_code/Histograms_Matching/EqualizeHist_Demo.cpp
@end_toggle
@add_toggle_java
- **Downloadable code**: Click
[here](https://github.com/opencv/opencv/tree/master/samples/java/tutorial_code/Histograms_Matching/histogram_equalization/EqualizeHistDemo.java)
- **Code at glance:**
@include samples/java/tutorial_code/Histograms_Matching/histogram_equalization/EqualizeHistDemo.java
@end_toggle
@add_toggle_python
- **Downloadable code**: Click
[here](https://github.com/opencv/opencv/tree/master/samples/python/tutorial_code/Histograms_Matching/histogram_equalization/EqualizeHist_Demo.py)
- **Code at glance:**
@include samples/python/tutorial_code/Histograms_Matching/histogram_equalization/EqualizeHist_Demo.py
@end_toggle
Explanation Explanation
----------- -----------
-# Declare the source and destination images as well as the windows names: - Load the source image:
@code{.cpp}
Mat src, dst;
char* source_window = "Source image"; @add_toggle_cpp
char* equalized_window = "Equalized Image"; @snippet samples/cpp/tutorial_code/Histograms_Matching/EqualizeHist_Demo.cpp Load image
@endcode @end_toggle
-# Load the source image:
@code{.cpp}
src = imread( argv[1], 1 );
if( !src.data ) @add_toggle_java
{ cout<<"Usage: ./Histogram_Demo <path_to_image>"<<endl; @snippet samples/java/tutorial_code/Histograms_Matching/histogram_equalization/EqualizeHistDemo.java Load image
return -1;} @end_toggle
@endcode
-# Convert it to grayscale: @add_toggle_python
@code{.cpp} @snippet samples/python/tutorial_code/Histograms_Matching/histogram_equalization/EqualizeHist_Demo.py Load image
cvtColor( src, src, COLOR_BGR2GRAY ); @end_toggle
@endcode
-# Apply histogram equalization with the function @ref cv::equalizeHist : - Convert it to grayscale:
@code{.cpp}
equalizeHist( src, dst ); @add_toggle_cpp
@endcode @snippet samples/cpp/tutorial_code/Histograms_Matching/EqualizeHist_Demo.cpp Convert to grayscale
@end_toggle
@add_toggle_java
@snippet samples/java/tutorial_code/Histograms_Matching/histogram_equalization/EqualizeHistDemo.java Convert to grayscale
@end_toggle
@add_toggle_python
@snippet samples/python/tutorial_code/Histograms_Matching/histogram_equalization/EqualizeHist_Demo.py Convert to grayscale
@end_toggle
- Apply histogram equalization with the function @ref cv::equalizeHist :
@add_toggle_cpp
@snippet samples/cpp/tutorial_code/Histograms_Matching/EqualizeHist_Demo.cpp Apply Histogram Equalization
@end_toggle
@add_toggle_java
@snippet samples/java/tutorial_code/Histograms_Matching/histogram_equalization/EqualizeHistDemo.java Apply Histogram Equalization
@end_toggle
@add_toggle_python
@snippet samples/python/tutorial_code/Histograms_Matching/histogram_equalization/EqualizeHist_Demo.py Apply Histogram Equalization
@end_toggle
As it can be easily seen, the only arguments are the original image and the output (equalized) As it can be easily seen, the only arguments are the original image and the output (equalized)
image. image.
-# Display both images (original and equalized) : - Display both images (original and equalized):
@code{.cpp}
namedWindow( source_window, WINDOW_AUTOSIZE );
namedWindow( equalized_window, WINDOW_AUTOSIZE );
imshow( source_window, src ); @add_toggle_cpp
imshow( equalized_window, dst ); @snippet samples/cpp/tutorial_code/Histograms_Matching/EqualizeHist_Demo.cpp Display results
@endcode @end_toggle
-# Wait until user exists the program
@code{.cpp} @add_toggle_java
waitKey(0); @snippet samples/java/tutorial_code/Histograms_Matching/histogram_equalization/EqualizeHistDemo.java Display results
return 0; @end_toggle
@endcode
@add_toggle_python
@snippet samples/python/tutorial_code/Histograms_Matching/histogram_equalization/EqualizeHist_Demo.py Display results
@end_toggle
- Wait until user exists the program
@add_toggle_cpp
@snippet samples/cpp/tutorial_code/Histograms_Matching/EqualizeHist_Demo.cpp Wait until user exits the program
@end_toggle
@add_toggle_java
@snippet samples/java/tutorial_code/Histograms_Matching/histogram_equalization/EqualizeHistDemo.java Wait until user exits the program
@end_toggle
@add_toggle_python
@snippet samples/python/tutorial_code/Histograms_Matching/histogram_equalization/EqualizeHist_Demo.py Wait until user exits the program
@end_toggle
Results Results
------- -------

201
doc/tutorials/imgproc/imgtrans/warp_affine/warp_affine.markdown
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@ -80,7 +80,7 @@ Theory
Code Code
---- ----
-# **What does this program do?** - **What does this program do?**
- Loads an image - Loads an image
- Applies an Affine Transform to the image. This transform is obtained from the relation - Applies an Affine Transform to the image. This transform is obtained from the relation
between three points. We use the function @ref cv::warpAffine for that purpose. between three points. We use the function @ref cv::warpAffine for that purpose.
@ -88,57 +88,88 @@ Code
the image center the image center
- Waits until the user exits the program - Waits until the user exits the program
-# The tutorial's code is shown below. You can also download it here @add_toggle_cpp
[here](https://github.com/opencv/opencv/tree/master/samples/cpp/tutorial_code/ImgTrans/Geometric_Transforms_Demo.cpp) - The tutorial's code is shown below. You can also download it
[here](https://raw.githubusercontent.com/opencv/opencv/master/samples/cpp/tutorial_code/ImgProc/Smoothing/Smoothing.cpp)
@include samples/cpp/tutorial_code/ImgTrans/Geometric_Transforms_Demo.cpp @include samples/cpp/tutorial_code/ImgTrans/Geometric_Transforms_Demo.cpp
@end_toggle
@add_toggle_java
- The tutorial's code is shown below. You can also download it
[here](https://raw.githubusercontent.com/opencv/opencv/master/samples/cpp/tutorial_code/ImgProc/Smoothing/Smoothing.cpp)
@include samples/java/tutorial_code/ImgTrans/warp_affine/GeometricTransformsDemo.java
@end_toggle
@add_toggle_python
- The tutorial's code is shown below. You can also download it
[here](https://raw.githubusercontent.com/opencv/opencv/master/samples/python/tutorial_code/ImgTrans/warp_affine/Geometric_Transforms_Demo.py)
@include samples/python/tutorial_code/ImgTrans/warp_affine/Geometric_Transforms_Demo.py
@end_toggle
Explanation Explanation
----------- -----------
-# Declare some variables we will use, such as the matrices to store our results and 2 arrays of - Load an image:
points to store the 2D points that define our Affine Transform.
@code{.cpp}
Point2f srcTri[3];
Point2f dstTri[3];
Mat rot_mat( 2, 3, CV_32FC1 ); @add_toggle_cpp
Mat warp_mat( 2, 3, CV_32FC1 ); @snippet samples/cpp/tutorial_code/ImgTrans/Geometric_Transforms_Demo.cpp Load the image
Mat src, warp_dst, warp_rotate_dst; @end_toggle
@endcode
-# Load an image: @add_toggle_java
@code{.cpp} @snippet samples/java/tutorial_code/ImgTrans/warp_affine/GeometricTransformsDemo.java Load the image
src = imread( argv[1], 1 ); @end_toggle
@endcode
-# Initialize the destination image as having the same size and type as the source: @add_toggle_python
@code{.cpp} @snippet samples/python/tutorial_code/ImgTrans/warp_affine/Geometric_Transforms_Demo.py Load the image
warp_dst = Mat::zeros( src.rows, src.cols, src.type() ); @end_toggle
@endcode
-# **Affine Transform:** As we explained in lines above, we need two sets of 3 points to derive the - **Affine Transform:** As we explained in lines above, we need two sets of 3 points to derive the
affine transform relation. Have a look: affine transform relation. Have a look:
@code{.cpp}
srcTri[0] = Point2f( 0, 0 );
srcTri[1] = Point2f( src.cols - 1, 0 );
srcTri[2] = Point2f( 0, src.rows - 1 );
dstTri[0] = Point2f( src.cols*0.0, src.rows*0.33 ); @add_toggle_cpp
dstTri[1] = Point2f( src.cols*0.85, src.rows*0.25 ); @snippet samples/cpp/tutorial_code/ImgTrans/Geometric_Transforms_Demo.cpp Set your 3 points to calculate the Affine Transform
dstTri[2] = Point2f( src.cols*0.15, src.rows*0.7 ); @end_toggle
@endcode
@add_toggle_java
@snippet samples/java/tutorial_code/ImgTrans/warp_affine/GeometricTransformsDemo.java Set your 3 points to calculate the Affine Transform
@end_toggle
@add_toggle_python
@snippet samples/python/tutorial_code/ImgTrans/warp_affine/Geometric_Transforms_Demo.py Set your 3 points to calculate the Affine Transform
@end_toggle
You may want to draw these points to get a better idea on how they change. Their locations are You may want to draw these points to get a better idea on how they change. Their locations are
approximately the same as the ones depicted in the example figure (in the Theory section). You approximately the same as the ones depicted in the example figure (in the Theory section). You
may note that the size and orientation of the triangle defined by the 3 points change. may note that the size and orientation of the triangle defined by the 3 points change.
-# Armed with both sets of points, we calculate the Affine Transform by using OpenCV function @ref - Armed with both sets of points, we calculate the Affine Transform by using OpenCV function @ref
cv::getAffineTransform : cv::getAffineTransform :
@code{.cpp}
warp_mat = getAffineTransform( srcTri, dstTri ); @add_toggle_cpp
@endcode @snippet samples/cpp/tutorial_code/ImgTrans/Geometric_Transforms_Demo.cpp Get the Affine Transform
@end_toggle
@add_toggle_java
@snippet samples/java/tutorial_code/ImgTrans/warp_affine/GeometricTransformsDemo.java Get the Affine Transform
@end_toggle
@add_toggle_python
@snippet samples/python/tutorial_code/ImgTrans/warp_affine/Geometric_Transforms_Demo.py Get the Affine Transform
@end_toggle
We get a \f$2 \times 3\f$ matrix as an output (in this case **warp_mat**) We get a \f$2 \times 3\f$ matrix as an output (in this case **warp_mat**)
-# We then apply the Affine Transform just found to the src image - We then apply the Affine Transform just found to the src image
@code{.cpp}
warpAffine( src, warp_dst, warp_mat, warp_dst.size() ); @add_toggle_cpp
@endcode @snippet samples/cpp/tutorial_code/ImgTrans/Geometric_Transforms_Demo.cpp Apply the Affine Transform just found to the src image
@end_toggle
@add_toggle_java
@snippet samples/java/tutorial_code/ImgTrans/warp_affine/GeometricTransformsDemo.java Apply the Affine Transform just found to the src image
@end_toggle
@add_toggle_python
@snippet samples/python/tutorial_code/ImgTrans/warp_affine/Geometric_Transforms_Demo.py Apply the Affine Transform just found to the src image
@end_toggle
with the following arguments: with the following arguments:
- **src**: Input image - **src**: Input image
@ -149,47 +180,87 @@ Explanation
We just got our first transformed image! We will display it in one bit. Before that, we also We just got our first transformed image! We will display it in one bit. Before that, we also
want to rotate it... want to rotate it...
-# **Rotate:** To rotate an image, we need to know two things: - **Rotate:** To rotate an image, we need to know two things:
-# The center with respect to which the image will rotate -# The center with respect to which the image will rotate
-# The angle to be rotated. In OpenCV a positive angle is counter-clockwise -# The angle to be rotated. In OpenCV a positive angle is counter-clockwise
-# *Optional:* A scale factor -# *Optional:* A scale factor
We define these parameters with the following snippet: We define these parameters with the following snippet:
@code{.cpp}
Point center = Point( warp_dst.cols/2, warp_dst.rows/2 ); @add_toggle_cpp
double angle = -50.0; @snippet samples/cpp/tutorial_code/ImgTrans/Geometric_Transforms_Demo.cpp Compute a rotation matrix with respect to the center of the image
double scale = 0.6; @end_toggle
@endcode
-# We generate the rotation matrix with the OpenCV function @ref cv::getRotationMatrix2D , which @add_toggle_java
@snippet samples/java/tutorial_code/ImgTrans/warp_affine/GeometricTransformsDemo.java Compute a rotation matrix with respect to the center of the image
@end_toggle
@add_toggle_python
@snippet samples/python/tutorial_code/ImgTrans/warp_affine/Geometric_Transforms_Demo.py Compute a rotation matrix with respect to the center of the image
@end_toggle
- We generate the rotation matrix with the OpenCV function @ref cv::getRotationMatrix2D , which
returns a \f$2 \times 3\f$ matrix (in this case *rot_mat*) returns a \f$2 \times 3\f$ matrix (in this case *rot_mat*)
@code{.cpp}
rot_mat = getRotationMatrix2D( center, angle, scale );
@endcode
-# We now apply the found rotation to the output of our previous Transformation.
@code{.cpp}
warpAffine( warp_dst, warp_rotate_dst, rot_mat, warp_dst.size() );
@endcode
-# Finally, we display our results in two windows plus the original image for good measure:
@code{.cpp}
namedWindow( source_window, WINDOW_AUTOSIZE );
imshow( source_window, src );
namedWindow( warp_window, WINDOW_AUTOSIZE ); @add_toggle_cpp
imshow( warp_window, warp_dst ); @snippet samples/cpp/tutorial_code/ImgTrans/Geometric_Transforms_Demo.cpp Get the rotation matrix with the specifications above
@end_toggle
namedWindow( warp_rotate_window, WINDOW_AUTOSIZE ); @add_toggle_java
imshow( warp_rotate_window, warp_rotate_dst ); @snippet samples/java/tutorial_code/ImgTrans/warp_affine/GeometricTransformsDemo.java Get the rotation matrix with the specifications above
@endcode @end_toggle
-# We just have to wait until the user exits the program
@code{.cpp} @add_toggle_python
waitKey(0); @snippet samples/python/tutorial_code/ImgTrans/warp_affine/Geometric_Transforms_Demo.py Get the rotation matrix with the specifications above
@endcode @end_toggle
- We now apply the found rotation to the output of our previous Transformation:
@add_toggle_cpp
@snippet samples/cpp/tutorial_code/ImgTrans/Geometric_Transforms_Demo.cpp Rotate the warped image
@end_toggle
@add_toggle_java
@snippet samples/java/tutorial_code/ImgTrans/warp_affine/GeometricTransformsDemo.java Rotate the warped image
@end_toggle
@add_toggle_python
@snippet samples/python/tutorial_code/ImgTrans/warp_affine/Geometric_Transforms_Demo.py Rotate the warped image
@end_toggle
- Finally, we display our results in two windows plus the original image for good measure:
@add_toggle_cpp
@snippet samples/cpp/tutorial_code/ImgTrans/Geometric_Transforms_Demo.cpp Show what you got
@end_toggle
@add_toggle_java
@snippet samples/java/tutorial_code/ImgTrans/warp_affine/GeometricTransformsDemo.java Show what you got
@end_toggle
@add_toggle_python
@snippet samples/python/tutorial_code/ImgTrans/warp_affine/Geometric_Transforms_Demo.py Show what you got
@end_toggle
- We just have to wait until the user exits the program
@add_toggle_cpp
@snippet samples/cpp/tutorial_code/ImgTrans/Geometric_Transforms_Demo.cpp Wait until user exits the program
@end_toggle
@add_toggle_java
@snippet samples/java/tutorial_code/ImgTrans/warp_affine/GeometricTransformsDemo.java Wait until user exits the program
@end_toggle
@add_toggle_python
@snippet samples/python/tutorial_code/ImgTrans/warp_affine/Geometric_Transforms_Demo.py Wait until user exits the program
@end_toggle
Result Result
------ ------
-# After compiling the code above, we can give it the path of an image as argument. For instance, - After compiling the code above, we can give it the path of an image as argument. For instance,
for a picture like: for a picture like:
![](images/Warp_Affine_Tutorial_Original_Image.jpg) ![](images/Warp_Affine_Tutorial_Original_Image.jpg)

10
doc/tutorials/imgproc/table_of_content_imgproc.markdown
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@ -165,6 +165,8 @@ In this section you will learn about the image processing (manipulation) functio
- @subpage tutorial_warp_affine - @subpage tutorial_warp_affine
*Languages:* C++, Java, Python
*Compatibility:* \> OpenCV 2.0 *Compatibility:* \> OpenCV 2.0
*Author:* Ana Huamán *Author:* Ana Huamán
@ -173,6 +175,8 @@ In this section you will learn about the image processing (manipulation) functio
- @subpage tutorial_histogram_equalization - @subpage tutorial_histogram_equalization
*Languages:* C++, Java, Python
*Compatibility:* \> OpenCV 2.0 *Compatibility:* \> OpenCV 2.0
*Author:* Ana Huamán *Author:* Ana Huamán
@ -181,6 +185,8 @@ In this section you will learn about the image processing (manipulation) functio
- @subpage tutorial_histogram_calculation - @subpage tutorial_histogram_calculation
*Languages:* C++, Java, Python
*Compatibility:* \> OpenCV 2.0 *Compatibility:* \> OpenCV 2.0
*Author:* Ana Huamán *Author:* Ana Huamán
@ -189,6 +195,8 @@ In this section you will learn about the image processing (manipulation) functio
- @subpage tutorial_histogram_comparison - @subpage tutorial_histogram_comparison
*Languages:* C++, Java, Python
*Compatibility:* \> OpenCV 2.0 *Compatibility:* \> OpenCV 2.0
*Author:* Ana Huamán *Author:* Ana Huamán
@ -197,6 +205,8 @@ In this section you will learn about the image processing (manipulation) functio
- @subpage tutorial_back_projection - @subpage tutorial_back_projection
*Languages:* C++, Java, Python
*Compatibility:* \> OpenCV 2.0 *Compatibility:* \> OpenCV 2.0
*Author:* Ana Huamán *Author:* Ana Huamán

52
samples/cpp/tutorial_code/Histograms_Matching/EqualizeHist_Demo.cpp
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@ -17,37 +17,35 @@ using namespace std;
*/ */
int main( int argc, char** argv ) int main( int argc, char** argv )
{ {
Mat src, dst; //! [Load image]
CommandLineParser parser( argc, argv, "{@input | ../data/lena.jpg | input image}" );
Mat src = imread( parser.get<String>( "@input" ), IMREAD_COLOR );
if( src.empty() )
{
cout << "Could not open or find the image!\n" << endl;
cout << "Usage: " << argv[0] << " <Input image>" << endl;
return -1;
}
//! [Load image]
const char* source_window = "Source image"; //! [Convert to grayscale]
const char* equalized_window = "Equalized Image"; cvtColor( src, src, COLOR_BGR2GRAY );
//! [Convert to grayscale]
/// Load image //! [Apply Histogram Equalization]
CommandLineParser parser( argc, argv, "{@input | ../data/lena.jpg | input image}" ); Mat dst;
src = imread( parser.get<String>( "@input" ), IMREAD_COLOR ); equalizeHist( src, dst );
if( src.empty() ) //! [Apply Histogram Equalization]
{
cout << "Could not open or find the image!\n" << endl;
cout << "Usage: " << argv[0] << " <Input image>" << endl;
return -1;
}
/// Convert to grayscale //! [Display results]
cvtColor( src, src, COLOR_BGR2GRAY ); imshow( "Source image", src );
imshow( "Equalized Image", dst );
//! [Display results]
/// Apply Histogram Equalization //! [Wait until user exits the program]
equalizeHist( src, dst ); waitKey();
//! [Wait until user exits the program]
/// Display results return 0;
namedWindow( source_window, WINDOW_AUTOSIZE );
namedWindow( equalized_window, WINDOW_AUTOSIZE );
imshow( source_window, src );
imshow( equalized_window, dst );
/// Wait until user exits the program
waitKey(0);
return 0;
} }

106
samples/cpp/tutorial_code/Histograms_Matching/calcBackProject_Demo1.cpp
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@ -14,79 +14,93 @@ using namespace cv;
using namespace std; using namespace std;
/// Global Variables /// Global Variables
Mat src; Mat hsv; Mat hue; Mat hue;
int bins = 25; int bins = 25;
/// Function Headers /// Function Headers
void Hist_and_Backproj(int, void* ); void Hist_and_Backproj(int, void* );
/** /**
* @function main * @function main
*/ */
int main( int, char** argv ) int main( int argc, char* argv[] )
{ {
/// Read the image //! [Read the image]
src = imread( argv[1], IMREAD_COLOR ); CommandLineParser parser( argc, argv, "{@input | | input image}" );
Mat src = imread( parser.get<String>( "@input" ) );
if( src.empty() ) if( src.empty() )
{ cout<<"Usage: ./calcBackProject_Demo1 <path_to_image>"<<endl; {
return -1; cout << "Could not open or find the image!\n" << endl;
cout << "Usage: " << argv[0] << " <Input image>" << endl;
return -1;
} }
//! [Read the image]
/// Transform it to HSV //! [Transform it to HSV]
cvtColor( src, hsv, COLOR_BGR2HSV ); Mat hsv;
cvtColor( src, hsv, COLOR_BGR2HSV );
//! [Transform it to HSV]
/// Use only the Hue value //! [Use only the Hue value]
hue.create( hsv.size(), hsv.depth() ); hue.create(hsv.size(), hsv.depth());
int ch[] = { 0, 0 }; int ch[] = { 0, 0 };
mixChannels( &hsv, 1, &hue, 1, ch, 1 ); mixChannels( &hsv, 1, &hue, 1, ch, 1 );
//! [Use only the Hue value]
/// Create Trackbar to enter the number of bins //! [Create Trackbar to enter the number of bins]
const char* window_image = "Source image"; const char* window_image = "Source image";
namedWindow( window_image, WINDOW_AUTOSIZE ); namedWindow( window_image );
createTrackbar("* Hue bins: ", window_image, &bins, 180, Hist_and_Backproj ); createTrackbar("* Hue bins: ", window_image, &bins, 180, Hist_and_Backproj );
Hist_and_Backproj(0, 0); Hist_and_Backproj(0, 0);
//! [Create Trackbar to enter the number of bins]
/// Show the image //! [Show the image]
imshow( window_image, src ); imshow( window_image, src );
// Wait until user exits the program
waitKey();
//! [Show the image]
/// Wait until user exits the program return 0;
waitKey(0);
return 0;
} }
/** /**
* @function Hist_and_Backproj * @function Hist_and_Backproj
* @brief Callback to Trackbar * @brief Callback to Trackbar
*/ */
void Hist_and_Backproj(int, void* ) void Hist_and_Backproj(int, void* )
{ {
MatND hist; //! [initialize]
int histSize = MAX( bins, 2 ); int histSize = MAX( bins, 2 );
float hue_range[] = { 0, 180 }; float hue_range[] = { 0, 180 };
const float* ranges = { hue_range }; const float* ranges = { hue_range };
//! [initialize]
/// Get the Histogram and normalize it //! [Get the Histogram and normalize it]
calcHist( &hue, 1, 0, Mat(), hist, 1, &histSize, &ranges, true, false ); Mat hist;
normalize( hist, hist, 0, 255, NORM_MINMAX, -1, Mat() ); calcHist( &hue, 1, 0, Mat(), hist, 1, &histSize, &ranges, true, false );
normalize( hist, hist, 0, 255, NORM_MINMAX, -1, Mat() );
//! [Get the Histogram and normalize it]
/// Get Backprojection //! [Get Backprojection]
MatND backproj; Mat backproj;
calcBackProject( &hue, 1, 0, hist, backproj, &ranges, 1, true ); calcBackProject( &hue, 1, 0, hist, backproj, &ranges, 1, true );
//! [Get Backprojection]
/// Draw the backproj //! [Draw the backproj]
imshow( "BackProj", backproj ); imshow( "BackProj", backproj );
//! [Draw the backproj]
/// Draw the histogram //! [Draw the histogram]
int w = 400; int h = 400; int w = 400, h = 400;
int bin_w = cvRound( (double) w / histSize ); int bin_w = cvRound( (double) w / histSize );
Mat histImg = Mat::zeros( w, h, CV_8UC3 ); Mat histImg = Mat::zeros( h, w, CV_8UC3 );
for( int i = 0; i < bins; i ++ ) for (int i = 0; i < bins; i++)
{ rectangle( histImg, Point( i*bin_w, h ), Point( (i+1)*bin_w, h - cvRound( hist.at<float>(i)*h/255.0 ) ), Scalar( 0, 0, 255 ), -1 ); } {
rectangle( histImg, Point( i*bin_w, h ), Point( (i+1)*bin_w, h - cvRound( hist.at<float>(i)*h/255.0 ) ),
imshow( "Histogram", histImg ); Scalar( 0, 0, 255 ), FILLED );
}
imshow( "Histogram", histImg );
//! [Draw the histogram]
} }

93
samples/cpp/tutorial_code/Histograms_Matching/calcBackProject_Demo2.cpp
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@ -14,10 +14,9 @@ using namespace cv;
using namespace std; using namespace std;
/// Global Variables /// Global Variables
Mat src; Mat hsv; Mat src, hsv, mask;
Mat mask;
int lo = 20; int up = 20; int low = 20, up = 20;
const char* window_image = "Source image"; const char* window_image = "Source image";
/// Function Headers /// Function Headers
@ -29,23 +28,24 @@ void pickPoint (int event, int x, int y, int, void* );
*/ */
int main( int, char** argv ) int main( int, char** argv )
{ {
/// Read the image /// Read the image
src = imread( argv[1], IMREAD_COLOR ); src = imread( argv[1] );
/// Transform it to HSV
cvtColor( src, hsv, COLOR_BGR2HSV );
/// Show the image /// Transform it to HSV
namedWindow( window_image, WINDOW_AUTOSIZE ); cvtColor( src, hsv, COLOR_BGR2HSV );
imshow( window_image, src );
/// Set Trackbars for floodfill thresholds /// Show the image
createTrackbar( "Low thresh", window_image, &lo, 255, 0 ); namedWindow( window_image );
createTrackbar( "High thresh", window_image, &up, 255, 0 ); imshow( window_image, src );
/// Set a Mouse Callback
setMouseCallback( window_image, pickPoint, 0 );
waitKey(0); /// Set Trackbars for floodfill thresholds
return 0; createTrackbar( "Low thresh", window_image, &low, 255, 0 );
createTrackbar( "High thresh", window_image, &up, 255, 0 );
/// Set a Mouse Callback
setMouseCallback( window_image, pickPoint, 0 );
waitKey();
return 0;
} }
/** /**
@ -53,25 +53,27 @@ int main( int, char** argv )
*/ */
void pickPoint (int event, int x, int y, int, void* ) void pickPoint (int event, int x, int y, int, void* )
{ {
if( event != EVENT_LBUTTONDOWN ) if( event != EVENT_LBUTTONDOWN )
{ return; } {
return;
}
// Fill and get the mask // Fill and get the mask
Point seed = Point( x, y ); Point seed = Point( x, y );
int newMaskVal = 255; int newMaskVal = 255;
Scalar newVal = Scalar( 120, 120, 120 ); Scalar newVal = Scalar( 120, 120, 120 );
int connectivity = 8; int connectivity = 8;
int flags = connectivity + (newMaskVal << 8 ) + FLOODFILL_FIXED_RANGE + FLOODFILL_MASK_ONLY; int flags = connectivity + (newMaskVal << 8 ) + FLOODFILL_FIXED_RANGE + FLOODFILL_MASK_ONLY;
Mat mask2 = Mat::zeros( src.rows + 2, src.cols + 2, CV_8UC1 ); Mat mask2 = Mat::zeros( src.rows + 2, src.cols + 2, CV_8U );
floodFill( src, mask2, seed, newVal, 0, Scalar( lo, lo, lo ), Scalar( up, up, up), flags ); floodFill( src, mask2, seed, newVal, 0, Scalar( low, low, low ), Scalar( up, up, up), flags );
mask = mask2( Range( 1, mask2.rows - 1 ), Range( 1, mask2.cols - 1 ) ); mask = mask2( Range( 1, mask2.rows - 1 ), Range( 1, mask2.cols - 1 ) );
imshow( "Mask", mask ); imshow( "Mask", mask );
Hist_and_Backproj( ); Hist_and_Backproj( );
} }
/** /**
@ -79,26 +81,25 @@ void pickPoint (int event, int x, int y, int, void* )
*/ */
void Hist_and_Backproj( ) void Hist_and_Backproj( )
{ {
MatND hist; Mat hist;
int h_bins = 30; int s_bins = 32; int h_bins = 30; int s_bins = 32;
int histSize[] = { h_bins, s_bins }; int histSize[] = { h_bins, s_bins };
float h_range[] = { 0, 179 }; float h_range[] = { 0, 180 };
float s_range[] = { 0, 255 }; float s_range[] = { 0, 256 };
const float* ranges[] = { h_range, s_range }; const float* ranges[] = { h_range, s_range };
int channels[] = { 0, 1 }; int channels[] = { 0, 1 };
/// Get the Histogram and normalize it /// Get the Histogram and normalize it
calcHist( &hsv, 1, channels, mask, hist, 2, histSize, ranges, true, false ); calcHist( &hsv, 1, channels, mask, hist, 2, histSize, ranges, true, false );
normalize( hist, hist, 0, 255, NORM_MINMAX, -1, Mat() ); normalize( hist, hist, 0, 255, NORM_MINMAX, -1, Mat() );
/// Get Backprojection /// Get Backprojection
MatND backproj; Mat backproj;
calcBackProject( &hsv, 1, channels, hist, backproj, ranges, 1, true ); calcBackProject( &hsv, 1, channels, hist, backproj, ranges, 1, true );
/// Draw the backproj
imshow( "BackProj", backproj );
/// Draw the backproj
imshow( "BackProj", backproj );
} }

115
samples/cpp/tutorial_code/Histograms_Matching/calcHist_Demo.cpp
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@ -17,72 +17,73 @@ using namespace cv;
*/ */
int main(int argc, char** argv) int main(int argc, char** argv)
{ {
Mat src, dst; //! [Load image]
CommandLineParser parser( argc, argv, "{@input | ../data/lena.jpg | input image}" );
Mat src = imread( parser.get<String>( "@input" ), IMREAD_COLOR );
if( src.empty() )
{
return -1;
}
//! [Load image]
/// Load image //! [Separate the image in 3 places ( B, G and R )]
String imageName( "../data/lena.jpg" ); // by default vector<Mat> bgr_planes;
split( src, bgr_planes );
//! [Separate the image in 3 places ( B, G and R )]
if (argc > 1) //! [Establish the number of bins]
{ int histSize = 256;
imageName = argv[1]; //! [Establish the number of bins]
}
src = imread( imageName, IMREAD_COLOR ); //! [Set the ranges ( for B,G,R) )]
float range[] = { 0, 256 }; //the upper boundary is exclusive
const float* histRange = { range };
//! [Set the ranges ( for B,G,R) )]
if( src.empty() ) //! [Set histogram param]
{ return -1; } bool uniform = true, accumulate = false;
//! [Set histogram param]
/// Separate the image in 3 places ( B, G and R ) //! [Compute the histograms]
vector<Mat> bgr_planes; Mat b_hist, g_hist, r_hist;
split( src, bgr_planes ); calcHist( &bgr_planes[0], 1, 0, Mat(), b_hist, 1, &histSize, &histRange, uniform, accumulate );
calcHist( &bgr_planes[1], 1, 0, Mat(), g_hist, 1, &histSize, &histRange, uniform, accumulate );
calcHist( &bgr_planes[2], 1, 0, Mat(), r_hist, 1, &histSize, &histRange, uniform, accumulate );
//! [Compute the histograms]
/// Establish the number of bins //! [Draw the histograms for B, G and R]
int histSize = 256; int hist_w = 512, hist_h = 400;
int bin_w = cvRound( (double) hist_w/histSize );
/// Set the ranges ( for B,G,R) ) Mat histImage( hist_h, hist_w, CV_8UC3, Scalar( 0,0,0) );
float range[] = { 0, 256 } ; //! [Draw the histograms for B, G and R]
const float* histRange = { range };
bool uniform = true; bool accumulate = false; //! [Normalize the result to ( 0, histImage.rows )]
normalize(b_hist, b_hist, 0, histImage.rows, NORM_MINMAX, -1, Mat() );
normalize(g_hist, g_hist, 0, histImage.rows, NORM_MINMAX, -1, Mat() );
normalize(r_hist, r_hist, 0, histImage.rows, NORM_MINMAX, -1, Mat() );
//! [Normalize the result to ( 0, histImage.rows )]
Mat b_hist, g_hist, r_hist; //! [Draw for each channel]
for( int i = 1; i < histSize; i++ )
{
line( histImage, Point( bin_w*(i-1), hist_h - cvRound(b_hist.at<float>(i-1)) ),
Point( bin_w*(i), hist_h - cvRound(b_hist.at<float>(i)) ),
Scalar( 255, 0, 0), 2, 8, 0 );
line( histImage, Point( bin_w*(i-1), hist_h - cvRound(g_hist.at<float>(i-1)) ),
Point( bin_w*(i), hist_h - cvRound(g_hist.at<float>(i)) ),
Scalar( 0, 255, 0), 2, 8, 0 );
line( histImage, Point( bin_w*(i-1), hist_h - cvRound(r_hist.at<float>(i-1)) ),
Point( bin_w*(i), hist_h - cvRound(r_hist.at<float>(i)) ),
Scalar( 0, 0, 255), 2, 8, 0 );
}
//! [Draw for each channel]
/// Compute the histograms: //! [Display]
calcHist( &bgr_planes[0], 1, 0, Mat(), b_hist, 1, &histSize, &histRange, uniform, accumulate ); imshow("Source image", src );
calcHist( &bgr_planes[1], 1, 0, Mat(), g_hist, 1, &histSize, &histRange, uniform, accumulate ); imshow("calcHist Demo", histImage );
calcHist( &bgr_planes[2], 1, 0, Mat(), r_hist, 1, &histSize, &histRange, uniform, accumulate ); waitKey();
//! [Display]
// Draw the histograms for B, G and R
int hist_w = 512; int hist_h = 400;
int bin_w = cvRound( (double) hist_w/histSize );
Mat histImage( hist_h, hist_w, CV_8UC3, Scalar( 0,0,0) );
/// Normalize the result to [ 0, histImage.rows ]
normalize(b_hist, b_hist, 0, histImage.rows, NORM_MINMAX, -1, Mat() );
normalize(g_hist, g_hist, 0, histImage.rows, NORM_MINMAX, -1, Mat() );
normalize(r_hist, r_hist, 0, histImage.rows, NORM_MINMAX, -1, Mat() );
/// Draw for each channel
for( int i = 1; i < histSize; i++ )
{
line( histImage, Point( bin_w*(i-1), hist_h - cvRound(b_hist.at<float>(i-1)) ) ,
Point( bin_w*(i), hist_h - cvRound(b_hist.at<float>(i)) ),
Scalar( 255, 0, 0), 2, 8, 0 );
line( histImage, Point( bin_w*(i-1), hist_h - cvRound(g_hist.at<float>(i-1)) ) ,
Point( bin_w*(i), hist_h - cvRound(g_hist.at<float>(i)) ),
Scalar( 0, 255, 0), 2, 8, 0 );
line( histImage, Point( bin_w*(i-1), hist_h - cvRound(r_hist.at<float>(i-1)) ) ,
Point( bin_w*(i), hist_h - cvRound(r_hist.at<float>(i)) ),
Scalar( 0, 0, 255), 2, 8, 0 );
}
/// Display
namedWindow("calcHist Demo", WINDOW_AUTOSIZE );
imshow("calcHist Demo", histImage );
waitKey(0);
return 0;
return 0;
} }

70
samples/cpp/tutorial_code/Histograms_Matching/compareHist_Demo.cpp
View File

@ -12,42 +12,43 @@
using namespace std; using namespace std;
using namespace cv; using namespace cv;
const char* keys =
"{ help h| | Print help message. }"
"{ input1 | | Path to input image 1. }"
"{ input2 | | Path to input image 2. }"
"{ input3 | | Path to input image 3. }";
/** /**
* @function main * @function main
*/ */
int main( int argc, char** argv ) int main( int argc, char** argv )
{ {
Mat src_base, hsv_base; //! [Load three images with different environment settings]
Mat src_test1, hsv_test1; CommandLineParser parser( argc, argv, keys );
Mat src_test2, hsv_test2; Mat src_base = imread( parser.get<String>("input1") );
Mat hsv_half_down; Mat src_test1 = imread( parser.get<String>("input2") );
Mat src_test2 = imread( parser.get<String>("input3") );
/// Load three images with different environment settings if( src_base.empty() || src_test1.empty() || src_test2.empty() )
if( argc < 4 )
{ {
printf("** Error. Usage: ./compareHist_Demo <image_settings0> <image_settings1> <image_settings2>\n"); cout << "Could not open or find the images!\n" << endl;
parser.printMessage();
return -1; return -1;
} }
//! [Load three images with different environment settings]
src_base = imread( argv[1], IMREAD_COLOR ); //! [Convert to HSV]
src_test1 = imread( argv[2], IMREAD_COLOR ); Mat hsv_base, hsv_test1, hsv_test2;
src_test2 = imread( argv[3], IMREAD_COLOR );
if(src_base.empty() || src_test1.empty() || src_test2.empty())
{
cout << "Can't read one of the images" << endl;
return -1;
}
/// Convert to HSV
cvtColor( src_base, hsv_base, COLOR_BGR2HSV ); cvtColor( src_base, hsv_base, COLOR_BGR2HSV );
cvtColor( src_test1, hsv_test1, COLOR_BGR2HSV ); cvtColor( src_test1, hsv_test1, COLOR_BGR2HSV );
cvtColor( src_test2, hsv_test2, COLOR_BGR2HSV ); cvtColor( src_test2, hsv_test2, COLOR_BGR2HSV );
//! [Convert to HSV]
hsv_half_down = hsv_base( Range( hsv_base.rows/2, hsv_base.rows - 1 ), Range( 0, hsv_base.cols - 1 ) ); //! [Convert to HSV half]
Mat hsv_half_down = hsv_base( Range( hsv_base.rows/2, hsv_base.rows ), Range( 0, hsv_base.cols ) );
//! [Convert to HSV half]
/// Using 50 bins for hue and 60 for saturation //! [Using 50 bins for hue and 60 for saturation]
int h_bins = 50; int s_bins = 60; int h_bins = 50, s_bins = 60;
int histSize[] = { h_bins, s_bins }; int histSize[] = { h_bins, s_bins };
// hue varies from 0 to 179, saturation from 0 to 255 // hue varies from 0 to 179, saturation from 0 to 255
@ -56,17 +57,13 @@ int main( int argc, char** argv )
const float* ranges[] = { h_ranges, s_ranges }; const float* ranges[] = { h_ranges, s_ranges };
// Use the o-th and 1-st channels // Use the 0-th and 1-st channels
int channels[] = { 0, 1 }; int channels[] = { 0, 1 };
//! [Using 50 bins for hue and 60 for saturation]
//! [Calculate the histograms for the HSV images]
Mat hist_base, hist_half_down, hist_test1, hist_test2;
/// Histograms
MatND hist_base;
MatND hist_half_down;
MatND hist_test1;
MatND hist_test2;
/// Calculate the histograms for the HSV images
calcHist( &hsv_base, 1, channels, Mat(), hist_base, 2, histSize, ranges, true, false ); calcHist( &hsv_base, 1, channels, Mat(), hist_base, 2, histSize, ranges, true, false );
normalize( hist_base, hist_base, 0, 1, NORM_MINMAX, -1, Mat() ); normalize( hist_base, hist_base, 0, 1, NORM_MINMAX, -1, Mat() );
@ -78,20 +75,21 @@ int main( int argc, char** argv )
calcHist( &hsv_test2, 1, channels, Mat(), hist_test2, 2, histSize, ranges, true, false ); calcHist( &hsv_test2, 1, channels, Mat(), hist_test2, 2, histSize, ranges, true, false );
normalize( hist_test2, hist_test2, 0, 1, NORM_MINMAX, -1, Mat() ); normalize( hist_test2, hist_test2, 0, 1, NORM_MINMAX, -1, Mat() );
//! [Calculate the histograms for the HSV images]
/// Apply the histogram comparison methods //! [Apply the histogram comparison methods]
for( int i = 0; i < 4; i++ ) for( int compare_method = 0; compare_method < 4; compare_method++ )
{ {
int compare_method = i;
double base_base = compareHist( hist_base, hist_base, compare_method ); double base_base = compareHist( hist_base, hist_base, compare_method );
double base_half = compareHist( hist_base, hist_half_down, compare_method ); double base_half = compareHist( hist_base, hist_half_down, compare_method );
double base_test1 = compareHist( hist_base, hist_test1, compare_method ); double base_test1 = compareHist( hist_base, hist_test1, compare_method );
double base_test2 = compareHist( hist_base, hist_test2, compare_method ); double base_test2 = compareHist( hist_base, hist_test2, compare_method );
printf( " Method [%d] Perfect, Base-Half, Base-Test(1), Base-Test(2) : %f, %f, %f, %f \n", i, base_base, base_half , base_test1, base_test2 ); cout << "Method " << compare_method << " Perfect, Base-Half, Base-Test(1), Base-Test(2) : "
<< base_base << " / " << base_half << " / " << base_test1 << " / " << base_test2 << endl;
} }
//! [Apply the histogram comparison methods]
printf( "Done \n" ); cout << "Done \n";
return 0; return 0;
} }

106
samples/cpp/tutorial_code/ImgTrans/Geometric_Transforms_Demo.cpp
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@ -12,77 +12,71 @@
using namespace cv; using namespace cv;
using namespace std; using namespace std;
/// Global variables
const char* source_window = "Source image";
const char* warp_window = "Warp";
const char* warp_rotate_window = "Warp + Rotate";
/** /**
* @function main * @function main
*/ */
int main( int argc, char** argv ) int main( int argc, char** argv )
{ {
Point2f srcTri[3]; //! [Load the image]
Point2f dstTri[3]; CommandLineParser parser( argc, argv, "{@input | ../data/lena.jpg | input image}" );
Mat src = imread( parser.get<String>( "@input" ) );
if( src.empty() )
{
cout << "Could not open or find the image!\n" << endl;
cout << "Usage: " << argv[0] << " <Input image>" << endl;
return -1;
}
//! [Load the image]
Mat rot_mat( 2, 3, CV_32FC1 ); //! [Set your 3 points to calculate the Affine Transform]
Mat warp_mat( 2, 3, CV_32FC1 ); Point2f srcTri[3];
Mat src, warp_dst, warp_rotate_dst; srcTri[0] = Point2f( 0.f, 0.f );
srcTri[1] = Point2f( src.cols - 1.f, 0.f );
srcTri[2] = Point2f( 0.f, src.rows - 1.f );
/// Load the image Point2f dstTri[3];
CommandLineParser parser( argc, argv, "{@input | ../data/lena.jpg | input image}" ); dstTri[0] = Point2f( 0.f, src.rows*0.33f );
src = imread( parser.get<String>( "@input" ), IMREAD_COLOR ); dstTri[1] = Point2f( src.cols*0.85f, src.rows*0.25f );
if( src.empty() ) dstTri[2] = Point2f( src.cols*0.15f, src.rows*0.7f );
{ //! [Set your 3 points to calculate the Affine Transform]
cout << "Could not open or find the image!\n" << endl;
cout << "Usage: " << argv[0] << " <Input image>" << endl;
return -1;
}
/// Set the dst image the same type and size as src //! [Get the Affine Transform]
warp_dst = Mat::zeros( src.rows, src.cols, src.type() ); Mat warp_mat = getAffineTransform( srcTri, dstTri );
//! [Get the Affine Transform]
/// Set your 3 points to calculate the Affine Transform //! [Apply the Affine Transform just found to the src image]
srcTri[0] = Point2f( 0,0 ); /// Set the dst image the same type and size as src
srcTri[1] = Point2f( src.cols - 1.f, 0 ); Mat warp_dst = Mat::zeros( src.rows, src.cols, src.type() );
srcTri[2] = Point2f( 0, src.rows - 1.f );
dstTri[0] = Point2f( src.cols*0.0f, src.rows*0.33f ); warpAffine( src, warp_dst, warp_mat, warp_dst.size() );
dstTri[1] = Point2f( src.cols*0.85f, src.rows*0.25f ); //! [Apply the Affine Transform just found to the src image]
dstTri[2] = Point2f( src.cols*0.15f, src.rows*0.7f );
/// Get the Affine Transform /** Rotating the image after Warp */
warp_mat = getAffineTransform( srcTri, dstTri );
/// Apply the Affine Transform just found to the src image //! [Compute a rotation matrix with respect to the center of the image]
warpAffine( src, warp_dst, warp_mat, warp_dst.size() ); Point center = Point( warp_dst.cols/2, warp_dst.rows/2 );
double angle = -50.0;
double scale = 0.6;
//! [Compute a rotation matrix with respect to the center of the image]
/** Rotating the image after Warp */ //! [Get the rotation matrix with the specifications above]
Mat rot_mat = getRotationMatrix2D( center, angle, scale );
//! [Get the rotation matrix with the specifications above]
/// Compute a rotation matrix with respect to the center of the image //! [Rotate the warped image]
Point center = Point( warp_dst.cols/2, warp_dst.rows/2 ); Mat warp_rotate_dst;
double angle = -50.0; warpAffine( warp_dst, warp_rotate_dst, rot_mat, warp_dst.size() );
double scale = 0.6; //! [Rotate the warped image]
/// Get the rotation matrix with the specifications above //! [Show what you got]
rot_mat = getRotationMatrix2D( center, angle, scale ); imshow( "Source image", src );
imshow( "Warp", warp_dst );
imshow( "Warp + Rotate", warp_rotate_dst );
//! [Show what you got]
/// Rotate the warped image //! [Wait until user exits the program]
warpAffine( warp_dst, warp_rotate_dst, rot_mat, warp_dst.size() ); waitKey();
//! [Wait until user exits the program]
return 0;
/// Show what you got
namedWindow( source_window, WINDOW_AUTOSIZE );
imshow( source_window, src );
namedWindow( warp_window, WINDOW_AUTOSIZE );
imshow( warp_window, warp_dst );
namedWindow( warp_rotate_window, WINDOW_AUTOSIZE );
imshow( warp_rotate_window, warp_rotate_dst );
/// Wait until user exits the program
waitKey(0);
return 0;
} }

173
samples/java/tutorial_code/Histograms_Matching/back_projection/CalcBackProjectDemo1.java Normal file
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@ -0,0 +1,173 @@
import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.Image;
import java.util.Arrays;
import java.util.List;
import javax.swing.BoxLayout;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JSlider;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;
import org.opencv.core.Core;
import org.opencv.core.CvType;
import org.opencv.core.Mat;
import org.opencv.core.MatOfFloat;
import org.opencv.core.MatOfInt;
import org.opencv.core.Point;
import org.opencv.core.Scalar;
import org.opencv.highgui.HighGui;
import org.opencv.imgcodecs.Imgcodecs;
import org.opencv.imgproc.Imgproc;
class CalcBackProject1 {
private Mat hue;
private Mat histImg = new Mat();
private JFrame frame;
private JLabel imgLabel;
private JLabel backprojLabel;
private JLabel histImgLabel;
private static final int MAX_SLIDER = 180;
private int bins = 25;
public CalcBackProject1(String[] args) {
//! [Read the image]
if (args.length != 1) {
System.err.println("You must supply one argument that corresponds to the path to the image.");
System.exit(0);
}
Mat src = Imgcodecs.imread(args[0]);
if (src.empty()) {
System.err.println("Empty image: " + args[0]);
System.exit(0);
}
//! [Read the image]
//! [Transform it to HSV]
Mat hsv = new Mat();
Imgproc.cvtColor(src, hsv, Imgproc.COLOR_BGR2HSV);
//! [Transform it to HSV]
//! [Use only the Hue value]
hue = new Mat(hsv.size(), hsv.depth());
Core.mixChannels(Arrays.asList(hsv), Arrays.asList(hue), new MatOfInt(0, 0));
//! [Use only the Hue value]
// Create and set up the window.
frame = new JFrame("Back Projection 1 demo");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
// Set up the content pane.
Image img = HighGui.toBufferedImage(src);
addComponentsToPane(frame.getContentPane(), img);
//! [Show the image]
// Use the content pane's default BorderLayout. No need for
// setLayout(new BorderLayout());
// Display the window.
frame.pack();
frame.setVisible(true);
//! [Show the image]
}
private void addComponentsToPane(Container pane, Image img) {
if (!(pane.getLayout() instanceof BorderLayout)) {
pane.add(new JLabel("Container doesn't use BorderLayout!"));
return;
}
//! [Create Trackbar to enter the number of bins]
JPanel sliderPanel = new JPanel();
sliderPanel.setLayout(new BoxLayout(sliderPanel, BoxLayout.PAGE_AXIS));
sliderPanel.add(new JLabel("* Hue bins: "));
JSlider slider = new JSlider(0, MAX_SLIDER, bins);
slider.setMajorTickSpacing(25);
slider.setMinorTickSpacing(5);
slider.setPaintTicks(true);
slider.setPaintLabels(true);
slider.addChangeListener(new ChangeListener() {
@Override
public void stateChanged(ChangeEvent e) {
JSlider source = (JSlider) e.getSource();
bins = source.getValue();
update();
}
});
sliderPanel.add(slider);
pane.add(sliderPanel, BorderLayout.PAGE_START);
//! [Create Trackbar to enter the number of bins]
JPanel imgPanel = new JPanel();
imgLabel = new JLabel(new ImageIcon(img));
imgPanel.add(imgLabel);
backprojLabel = new JLabel();
imgPanel.add(backprojLabel);
histImgLabel = new JLabel();
imgPanel.add(histImgLabel);
pane.add(imgPanel, BorderLayout.CENTER);
}
private void update() {
//! [initialize]
int histSize = Math.max(bins, 2);
float[] hueRange = {0, 180};
//! [initialize]
//! [Get the Histogram and normalize it]
Mat hist = new Mat();
List<Mat> hueList = Arrays.asList(hue);
Imgproc.calcHist(hueList, new MatOfInt(0), new Mat(), hist, new MatOfInt(histSize), new MatOfFloat(hueRange), false);
Core.normalize(hist, hist, 0, 255, Core.NORM_MINMAX);
//! [Get the Histogram and normalize it]
//! [Get Backprojection]
Mat backproj = new Mat();
Imgproc.calcBackProject(hueList, new MatOfInt(0), hist, backproj, new MatOfFloat(hueRange), 1);
//! [Get Backprojection]
//! [Draw the backproj]
Image backprojImg = HighGui.toBufferedImage(backproj);
backprojLabel.setIcon(new ImageIcon(backprojImg));
//! [Draw the backproj]
//! [Draw the histogram]
int w = 400, h = 400;
int binW = (int) Math.round((double) w / histSize);
histImg = Mat.zeros(h, w, CvType.CV_8UC3);
float[] histData = new float[(int) (hist.total() * hist.channels())];
hist.get(0, 0, histData);
for (int i = 0; i < bins; i++) {
Imgproc.rectangle(histImg, new Point(i * binW, h),
new Point((i + 1) * binW, h - Math.round(histData[i] * h / 255.0)), new Scalar(0, 0, 255), Core.FILLED);
}
Image histImage = HighGui.toBufferedImage(histImg);
histImgLabel.setIcon(new ImageIcon(histImage));
//! [Draw the histogram]
frame.repaint();
frame.pack();
}
}
public class CalcBackProjectDemo1 {
public static void main(String[] args) {
// Load the native OpenCV library
System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
// Schedule a job for the event dispatch thread:
// creating and showing this application's GUI.
javax.swing.SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
new CalcBackProject1(args);
}
});
}
}

189
samples/java/tutorial_code/Histograms_Matching/back_projection/CalcBackProjectDemo2.java Normal file
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@ -0,0 +1,189 @@
import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.Image;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.util.Arrays;
import java.util.List;
import javax.swing.BoxLayout;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JSlider;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;
import org.opencv.core.Core;
import org.opencv.core.CvType;
import org.opencv.core.Mat;
import org.opencv.core.MatOfFloat;
import org.opencv.core.MatOfInt;
import org.opencv.core.Point;
import org.opencv.core.Range;
import org.opencv.core.Rect;
import org.opencv.core.Scalar;
import org.opencv.highgui.HighGui;
import org.opencv.imgcodecs.Imgcodecs;
import org.opencv.imgproc.Imgproc;
class CalcBackProject2 {
private Mat src;
private Mat hsv = new Mat();
private Mat mask = new Mat();
private JFrame frame;
private JLabel imgLabel;
private JLabel backprojLabel;
private JLabel maskImgLabel;
private static final int MAX_SLIDER = 255;
private int low = 20;
private int up = 20;
public CalcBackProject2(String[] args) {
/// Read the image
if (args.length != 1) {
System.err.println("You must supply one argument that corresponds to the path to the image.");
System.exit(0);
}
src = Imgcodecs.imread(args[0]);
if (src.empty()) {
System.err.println("Empty image: " + args[0]);
System.exit(0);
}
/// Transform it to HSV
Imgproc.cvtColor(src, hsv, Imgproc.COLOR_BGR2HSV);
// Create and set up the window.
frame = new JFrame("Back Projection 2 demo");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
// Set up the content pane.
Image img = HighGui.toBufferedImage(src);
addComponentsToPane(frame.getContentPane(), img);
// Use the content pane's default BorderLayout. No need for
// setLayout(new BorderLayout());
// Display the window.
frame.pack();
frame.setVisible(true);
}
private void addComponentsToPane(Container pane, Image img) {
if (!(pane.getLayout() instanceof BorderLayout)) {
pane.add(new JLabel("Container doesn't use BorderLayout!"));
return;
}
/// Set Trackbars for floodfill thresholds
JPanel sliderPanel = new JPanel();
sliderPanel.setLayout(new BoxLayout(sliderPanel, BoxLayout.PAGE_AXIS));
sliderPanel.add(new JLabel("Low thresh"));
JSlider slider = new JSlider(0, MAX_SLIDER, low);
slider.setMajorTickSpacing(20);
slider.setMinorTickSpacing(10);
slider.setPaintTicks(true);
slider.setPaintLabels(true);
slider.addChangeListener(new ChangeListener() {
@Override
public void stateChanged(ChangeEvent e) {
JSlider source = (JSlider) e.getSource();
low = source.getValue();
}
});
sliderPanel.add(slider);
pane.add(sliderPanel, BorderLayout.PAGE_START);
sliderPanel.add(new JLabel("High thresh"));
slider = new JSlider(0, MAX_SLIDER, up);
slider.setMajorTickSpacing(20);
slider.setMinorTickSpacing(10);
slider.setPaintTicks(true);
slider.setPaintLabels(true);
slider.addChangeListener(new ChangeListener() {
@Override
public void stateChanged(ChangeEvent e) {
JSlider source = (JSlider) e.getSource();
up = source.getValue();
}
});
sliderPanel.add(slider);
pane.add(sliderPanel, BorderLayout.PAGE_START);
JPanel imgPanel = new JPanel();
imgLabel = new JLabel(new ImageIcon(img));
/// Set a Mouse Callback
imgLabel.addMouseListener(new MouseAdapter() {
@Override
public void mousePressed(MouseEvent e) {
update(e.getX(), e.getY());
}
});
imgPanel.add(imgLabel);
maskImgLabel = new JLabel();
imgPanel.add(maskImgLabel);
backprojLabel = new JLabel();
imgPanel.add(backprojLabel);
pane.add(imgPanel, BorderLayout.CENTER);
}
private void update(int x, int y) {
// Fill and get the mask
Point seed = new Point(x, y);
int newMaskVal = 255;
Scalar newVal = new Scalar(120, 120, 120);
int connectivity = 8;
int flags = connectivity + (newMaskVal << 8) + Imgproc.FLOODFILL_FIXED_RANGE + Imgproc.FLOODFILL_MASK_ONLY;
Mat mask2 = Mat.zeros(src.rows() + 2, src.cols() + 2, CvType.CV_8U);
Imgproc.floodFill(src, mask2, seed, newVal, new Rect(), new Scalar(low, low, low), new Scalar(up, up, up), flags);
mask = mask2.submat(new Range(1, mask2.rows() - 1), new Range(1, mask2.cols() - 1));
Image maskImg = HighGui.toBufferedImage(mask);
maskImgLabel.setIcon(new ImageIcon(maskImg));
int hBins = 30, sBins = 32;
int[] histSize = { hBins, sBins };
float[] ranges = { 0, 180, 0, 256 };
int[] channels = { 0, 1 };
/// Get the Histogram and normalize it
Mat hist = new Mat();
List<Mat> hsvList = Arrays.asList(hsv);
Imgproc.calcHist(hsvList, new MatOfInt(channels), mask, hist, new MatOfInt(histSize), new MatOfFloat(ranges), false );
Core.normalize(hist, hist, 0, 255, Core.NORM_MINMAX);
/// Get Backprojection
Mat backproj = new Mat();
Imgproc.calcBackProject(hsvList, new MatOfInt(channels), hist, backproj, new MatOfFloat(ranges), 1);
Image backprojImg = HighGui.toBufferedImage(backproj);
backprojLabel.setIcon(new ImageIcon(backprojImg));
frame.repaint();
frame.pack();
}
}
public class CalcBackProjectDemo2 {
public static void main(String[] args) {
// Load the native OpenCV library
System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
// Schedule a job for the event dispatch thread:
// creating and showing this application's GUI.
javax.swing.SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
new CalcBackProject2(args);
}
});
}
}

99
samples/java/tutorial_code/Histograms_Matching/histogram_calculation/CalcHistDemo.java Normal file
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@ -0,0 +1,99 @@
import java.util.ArrayList;
import java.util.List;
import org.opencv.core.Core;
import org.opencv.core.CvType;
import org.opencv.core.Mat;
import org.opencv.core.MatOfFloat;
import org.opencv.core.MatOfInt;
import org.opencv.core.Point;
import org.opencv.core.Scalar;
import org.opencv.highgui.HighGui;
import org.opencv.imgcodecs.Imgcodecs;
import org.opencv.imgproc.Imgproc;
class CalcHist {
public void run(String[] args) {
//! [Load image]
String filename = args.length > 0 ? args[0] : "../data/lena.jpg";
Mat src = Imgcodecs.imread(filename);
if (src.empty()) {
System.err.println("Cannot read image: " + filename);
System.exit(0);
}
//! [Load image]
//! [Separate the image in 3 places ( B, G and R )]
List<Mat> bgrPlanes = new ArrayList<>();
Core.split(src, bgrPlanes);
//! [Separate the image in 3 places ( B, G and R )]
//! [Establish the number of bins]
int histSize = 256;
//! [Establish the number of bins]
//! [Set the ranges ( for B,G,R) )]
float[] range = {0, 256}; //the upper boundary is exclusive
MatOfFloat histRange = new MatOfFloat(range);
//! [Set the ranges ( for B,G,R) )]
//! [Set histogram param]
boolean accumulate = false;
//! [Set histogram param]
//! [Compute the histograms]
Mat bHist = new Mat(), gHist = new Mat(), rHist = new Mat();
Imgproc.calcHist(bgrPlanes, new MatOfInt(0), new Mat(), bHist, new MatOfInt(histSize), histRange, accumulate);
Imgproc.calcHist(bgrPlanes, new MatOfInt(1), new Mat(), gHist, new MatOfInt(histSize), histRange, accumulate);
Imgproc.calcHist(bgrPlanes, new MatOfInt(2), new Mat(), rHist, new MatOfInt(histSize), histRange, accumulate);
//! [Compute the histograms]
//! [Draw the histograms for B, G and R]
int histW = 512, histH = 400;
int binW = (int) Math.round((double) histW / histSize);
Mat histImage = new Mat( histH, histW, CvType.CV_8UC3, new Scalar( 0,0,0) );
//! [Draw the histograms for B, G and R]
//! [Normalize the result to ( 0, histImage.rows )]
Core.normalize(bHist, bHist, 0, histImage.rows(), Core.NORM_MINMAX);
Core.normalize(gHist, gHist, 0, histImage.rows(), Core.NORM_MINMAX);
Core.normalize(rHist, rHist, 0, histImage.rows(), Core.NORM_MINMAX);
//! [Normalize the result to ( 0, histImage.rows )]
//! [Draw for each channel]
float[] bHistData = new float[(int) (bHist.total() * bHist.channels())];
bHist.get(0, 0, bHistData);
float[] gHistData = new float[(int) (gHist.total() * gHist.channels())];
gHist.get(0, 0, gHistData);
float[] rHistData = new float[(int) (rHist.total() * rHist.channels())];
rHist.get(0, 0, rHistData);
for( int i = 1; i < histSize; i++ ) {
Imgproc.line(histImage, new Point(binW * (i - 1), histH - Math.round(bHistData[i - 1])),
new Point(binW * (i), histH - Math.round(bHistData[i])), new Scalar(255, 0, 0), 2);
Imgproc.line(histImage, new Point(binW * (i - 1), histH - Math.round(gHistData[i - 1])),
new Point(binW * (i), histH - Math.round(gHistData[i])), new Scalar(0, 255, 0), 2);
Imgproc.line(histImage, new Point(binW * (i - 1), histH - Math.round(rHistData[i - 1])),
new Point(binW * (i), histH - Math.round(rHistData[i])), new Scalar(0, 0, 255), 2);
}
//! [Draw for each channel]
//! [Display]
HighGui.imshow( "Source image", src );
HighGui.imshow( "calcHist Demo", histImage );
HighGui.waitKey(0);
//! [Display]
System.exit(0);
}
}
public class CalcHistDemo {
public static void main(String[] args) {
// Load the native OpenCV library
System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
new CalcHist().run(args);
}
}

91
samples/java/tutorial_code/Histograms_Matching/histogram_comparison/CompareHistDemo.java Normal file
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@ -0,0 +1,91 @@
import java.util.Arrays;
import java.util.List;
import org.opencv.core.Core;
import org.opencv.core.Mat;
import org.opencv.core.MatOfFloat;
import org.opencv.core.MatOfInt;
import org.opencv.core.Range;
import org.opencv.imgcodecs.Imgcodecs;
import org.opencv.imgproc.Imgproc;
class CompareHist {
public void run(String[] args) {
//! [Load three images with different environment settings]
if (args.length != 3) {
System.err.println("You must supply 3 arguments that correspond to the paths to 3 images.");
System.exit(0);
}
Mat srcBase = Imgcodecs.imread(args[0]);
Mat srcTest1 = Imgcodecs.imread(args[1]);
Mat srcTest2 = Imgcodecs.imread(args[2]);
if (srcBase.empty() || srcTest1.empty() || srcTest2.empty()) {
System.err.println("Cannot read the images");
System.exit(0);
}
//! [Load three images with different environment settings]
//! [Convert to HSV]
Mat hsvBase = new Mat(), hsvTest1 = new Mat(), hsvTest2 = new Mat();
Imgproc.cvtColor( srcBase, hsvBase, Imgproc.COLOR_BGR2HSV );
Imgproc.cvtColor( srcTest1, hsvTest1, Imgproc.COLOR_BGR2HSV );
Imgproc.cvtColor( srcTest2, hsvTest2, Imgproc.COLOR_BGR2HSV );
//! [Convert to HSV]
//! [Convert to HSV half]
Mat hsvHalfDown = hsvBase.submat( new Range( hsvBase.rows()/2, hsvBase.rows() - 1 ), new Range( 0, hsvBase.cols() - 1 ) );
//! [Convert to HSV half]
//! [Using 50 bins for hue and 60 for saturation]
int hBins = 50, sBins = 60;
int[] histSize = { hBins, sBins };
// hue varies from 0 to 179, saturation from 0 to 255
float[] ranges = { 0, 180, 0, 256 };
// Use the 0-th and 1-st channels
int[] channels = { 0, 1 };
//! [Using 50 bins for hue and 60 for saturation]
//! [Calculate the histograms for the HSV images]
Mat histBase = new Mat(), histHalfDown = new Mat(), histTest1 = new Mat(), histTest2 = new Mat();
List<Mat> hsvBaseList = Arrays.asList(hsvBase);
Imgproc.calcHist(hsvBaseList, new MatOfInt(channels), new Mat(), histBase, new MatOfInt(histSize), new MatOfFloat(ranges), false);
Core.normalize(histBase, histBase, 0, 1, Core.NORM_MINMAX);
List<Mat> hsvHalfDownList = Arrays.asList(hsvHalfDown);
Imgproc.calcHist(hsvHalfDownList, new MatOfInt(channels), new Mat(), histHalfDown, new MatOfInt(histSize), new MatOfFloat(ranges), false);
Core.normalize(histHalfDown, histHalfDown, 0, 1, Core.NORM_MINMAX);
List<Mat> hsvTest1List = Arrays.asList(hsvTest1);
Imgproc.calcHist(hsvTest1List, new MatOfInt(channels), new Mat(), histTest1, new MatOfInt(histSize), new MatOfFloat(ranges), false);
Core.normalize(histTest1, histTest1, 0, 1, Core.NORM_MINMAX);
List<Mat> hsvTest2List = Arrays.asList(hsvTest2);
Imgproc.calcHist(hsvTest2List, new MatOfInt(channels), new Mat(), histTest2, new MatOfInt(histSize), new MatOfFloat(ranges), false);
Core.normalize(histTest2, histTest2, 0, 1, Core.NORM_MINMAX);
//! [Calculate the histograms for the HSV images]
//! [Apply the histogram comparison methods]
for( int compareMethod = 0; compareMethod < 4; compareMethod++ ) {
double baseBase = Imgproc.compareHist( histBase, histBase, compareMethod );
double baseHalf = Imgproc.compareHist( histBase, histHalfDown, compareMethod );
double baseTest1 = Imgproc.compareHist( histBase, histTest1, compareMethod );
double baseTest2 = Imgproc.compareHist( histBase, histTest2, compareMethod );
System.out.println("Method " + compareMethod + " Perfect, Base-Half, Base-Test(1), Base-Test(2) : " + baseBase + " / " + baseHalf
+ " / " + baseTest1 + " / " + baseTest2);
}
//! [Apply the histogram comparison methods]
}
}
public class CompareHistDemo {
public static void main(String[] args) {
// Load the native OpenCV library
System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
new CompareHist().run(args);
}
}

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samples/java/tutorial_code/Histograms_Matching/histogram_equalization/EqualizeHistDemo.java Normal file
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import org.opencv.core.Core;
import org.opencv.core.Mat;
import org.opencv.highgui.HighGui;
import org.opencv.imgcodecs.Imgcodecs;
import org.opencv.imgproc.Imgproc;
class EqualizeHist {
public void run(String[] args) {
//! [Load image]
String filename = args.length > 0 ? args[0] : "../data/lena.jpg";
Mat src = Imgcodecs.imread(filename);
if (src.empty()) {
System.err.println("Cannot read image: " + filename);
System.exit(0);
}
//! [Load image]
//! [Convert to grayscale]
Imgproc.cvtColor(src, src, Imgproc.COLOR_BGR2GRAY);
//! [Convert to grayscale]
//! [Apply Histogram Equalization]
Mat dst = new Mat();
Imgproc.equalizeHist( src, dst );
//! [Apply Histogram Equalization]
//! [Display results]
HighGui.imshow( "Source image", src );
HighGui.imshow( "Equalized Image", dst );
//! [Display results]
//! [Wait until user exits the program]
HighGui.waitKey(0);
//! [Wait until user exits the program]
System.exit(0);
}
}
public class EqualizeHistDemo {
public static void main(String[] args) {
// Load the native OpenCV library
System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
new EqualizeHist().run(args);
}
}

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samples/java/tutorial_code/ImgTrans/warp_affine/GeometricTransformsDemo.java Normal file
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import org.opencv.core.Core;
import org.opencv.core.Mat;
import org.opencv.core.MatOfPoint2f;
import org.opencv.core.Point;
import org.opencv.highgui.HighGui;
import org.opencv.imgcodecs.Imgcodecs;
import org.opencv.imgproc.Imgproc;
class GeometricTransforms {
public void run(String[] args) {
//! [Load the image]
String filename = args.length > 0 ? args[0] : "../data/lena.jpg";
Mat src = Imgcodecs.imread(filename);
if (src.empty()) {
System.err.println("Cannot read image: " + filename);
System.exit(0);
}
//! [Load the image]
//! [Set your 3 points to calculate the Affine Transform]
Point[] srcTri = new Point[3];
srcTri[0] = new Point( 0, 0 );
srcTri[1] = new Point( src.cols() - 1, 0 );
srcTri[2] = new Point( 0, src.rows() - 1 );
Point[] dstTri = new Point[3];
dstTri[0] = new Point( 0, src.rows()*0.33 );
dstTri[1] = new Point( src.cols()*0.85, src.rows()*0.25 );
dstTri[2] = new Point( src.cols()*0.15, src.rows()*0.7 );
//! [Set your 3 points to calculate the Affine Transform]
//! [Get the Affine Transform]
Mat warpMat = Imgproc.getAffineTransform( new MatOfPoint2f(srcTri), new MatOfPoint2f(dstTri) );
//! [Get the Affine Transform]
//! [Apply the Affine Transform just found to the src image]
Mat warpDst = Mat.zeros( src.rows(), src.cols(), src.type() );
Imgproc.warpAffine( src, warpDst, warpMat, warpDst.size() );
//! [Apply the Affine Transform just found to the src image]
/** Rotating the image after Warp */
//! [Compute a rotation matrix with respect to the center of the image]
Point center = new Point(warpDst.cols() / 2, warpDst.rows() / 2);
double angle = -50.0;
double scale = 0.6;
//! [Compute a rotation matrix with respect to the center of the image]
//! [Get the rotation matrix with the specifications above]
Mat rotMat = Imgproc.getRotationMatrix2D( center, angle, scale );
//! [Get the rotation matrix with the specifications above]
//! [Rotate the warped image]
Mat warpRotateDst = new Mat();
Imgproc.warpAffine( warpDst, warpRotateDst, rotMat, warpDst.size() );
//! [Rotate the warped image]
//! [Show what you got]
HighGui.imshow( "Source image", src );
HighGui.imshow( "Warp", warpDst );
HighGui.imshow( "Warp + Rotate", warpRotateDst );
//! [Show what you got]
//! [Wait until user exits the program]
HighGui.waitKey(0);
//! [Wait until user exits the program]
System.exit(0);
}
}
public class GeometricTransformsDemo {
public static void main(String[] args) {
// Load the native OpenCV library
System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
new GeometricTransforms().run(args);
}
}

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samples/python/tutorial_code/Histograms_Matching/back_projection/calcBackProject_Demo1.py Normal file
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from __future__ import print_function
from __future__ import division
import cv2 as cv
import numpy as np
import argparse
def Hist_and_Backproj(val):
## [initialize]
bins = val
histSize = max(bins, 2)
ranges = [0, 180] # hue_range
## [initialize]
## [Get the Histogram and normalize it]
hist = cv.calcHist([hue], [0], None, [histSize], ranges, accumulate=False)
cv.normalize(hist, hist, alpha=0, beta=255, norm_type=cv.NORM_MINMAX)
## [Get the Histogram and normalize it]
## [Get Backprojection]
backproj = cv.calcBackProject([hue], [0], hist, ranges, scale=1)
## [Get Backprojection]
## [Draw the backproj]
cv.imshow('BackProj', backproj)
## [Draw the backproj]
## [Draw the histogram]
w = 400
h = 400
bin_w = int(round(w / histSize))
histImg = np.zeros((h, w, 3), dtype=np.uint8)
for i in range(bins):
cv.rectangle(histImg, (i*bin_w, h), ( (i+1)*bin_w, h - int(round( hist[i]*h/255.0 )) ), (0, 0, 255), cv.FILLED)
cv.imshow('Histogram', histImg)
## [Draw the histogram]
## [Read the image]
parser = argparse.ArgumentParser(description='Code for Back Projection tutorial.')
parser.add_argument('--input', help='Path to input image.')
args = parser.parse_args()
src = cv.imread(args.input)
if src is None:
print('Could not open or find the image:', args.input)
exit(0)
## [Read the image]
## [Transform it to HSV]
hsv = cv.cvtColor(src, cv.COLOR_BGR2HSV)
## [Transform it to HSV]
## [Use only the Hue value]
ch = (0, 0)
hue = np.empty(hsv.shape, hsv.dtype)
cv.mixChannels([hsv], [hue], ch)
## [Use only the Hue value]
## [Create Trackbar to enter the number of bins]
window_image = 'Source image'
cv.namedWindow(window_image)
bins = 25
cv.createTrackbar('* Hue bins: ', window_image, bins, 180, Hist_and_Backproj )
Hist_and_Backproj(bins)
## [Create Trackbar to enter the number of bins]
## [Show the image]
cv.imshow(window_image, src)
cv.waitKey()
## [Show the image]

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samples/python/tutorial_code/Histograms_Matching/back_projection/calcBackProject_Demo2.py Normal file
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from __future__ import print_function
import cv2 as cv
import numpy as np
import argparse
low = 20
up = 20
def callback_low(val):
global low
low = val
def callback_up(val):
global up
up = val
def pickPoint(event, x, y, flags, param):
if event != cv.EVENT_LBUTTONDOWN:
return
# Fill and get the mask
seed = (x, y)
newMaskVal = 255
newVal = (120, 120, 120)
connectivity = 8
flags = connectivity + (newMaskVal << 8 ) + cv.FLOODFILL_FIXED_RANGE + cv.FLOODFILL_MASK_ONLY
mask2 = np.zeros((src.shape[0] + 2, src.shape[1] + 2), dtype=np.uint8)
print('low:', low, 'up:', up)
cv.floodFill(src, mask2, seed, newVal, (low, low, low), (up, up, up), flags)
mask = mask2[1:-1,1:-1]
cv.imshow('Mask', mask)
Hist_and_Backproj(mask)
def Hist_and_Backproj(mask):
h_bins = 30
s_bins = 32
histSize = [h_bins, s_bins]
h_range = [0, 180]
s_range = [0, 256]
ranges = h_range + s_range # Concat list
channels = [0, 1]
# Get the Histogram and normalize it
hist = cv.calcHist([hsv], channels, mask, histSize, ranges, accumulate=False)
cv.normalize(hist, hist, alpha=0, beta=255, norm_type=cv.NORM_MINMAX)
# Get Backprojection
backproj = cv.calcBackProject([hsv], channels, hist, ranges, scale=1)
# Draw the backproj
cv.imshow('BackProj', backproj)
# Read the image
parser = argparse.ArgumentParser(description='Code for Back Projection tutorial.')
parser.add_argument('--input', help='Path to input image.')
args = parser.parse_args()
src = cv.imread(args.input)
if src is None:
print('Could not open or find the image:', args.input)
exit(0)
# Transform it to HSV
hsv = cv.cvtColor(src, cv.COLOR_BGR2HSV)
# Show the image
window_image = 'Source image'
cv.namedWindow(window_image)
cv.imshow(window_image, src)
# Set Trackbars for floodfill thresholds
cv.createTrackbar('Low thresh', window_image, low, 255, callback_low)
cv.createTrackbar('High thresh', window_image, up, 255, callback_up)
# Set a Mouse Callback
cv.setMouseCallback(window_image, pickPoint)
cv.waitKey()

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samples/python/tutorial_code/Histograms_Matching/histogram_calculation/calcHist_Demo.py Normal file
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from __future__ import print_function
from __future__ import division
import cv2 as cv
import numpy as np
import argparse
## [Load image]
parser = argparse.ArgumentParser(description='Code for Histogram Calculation tutorial.')
parser.add_argument('--input', help='Path to input image.', default='../data/lena.jpg')
args = parser.parse_args()
src = cv.imread(args.input)
if src is None:
print('Could not open or find the image:', args.input)
exit(0)
## [Load image]
## [Separate the image in 3 places ( B, G and R )]
bgr_planes = cv.split(src)
## [Separate the image in 3 places ( B, G and R )]
## [Establish the number of bins]
histSize = 256
## [Establish the number of bins]
## [Set the ranges ( for B,G,R) )]
histRange = (0, 256) # the upper boundary is exclusive
## [Set the ranges ( for B,G,R) )]
## [Set histogram param]
accumulate = False
## [Set histogram param]
## [Compute the histograms]
b_hist = cv.calcHist(bgr_planes, [0], None, [histSize], histRange, accumulate=accumulate)
g_hist = cv.calcHist(bgr_planes, [1], None, [histSize], histRange, accumulate=accumulate)
r_hist = cv.calcHist(bgr_planes, [2], None, [histSize], histRange, accumulate=accumulate)
## [Compute the histograms]
## [Draw the histograms for B, G and R]
hist_w = 512
hist_h = 400
bin_w = int(round( hist_w/histSize ))
histImage = np.zeros((hist_h, hist_w, 3), dtype=np.uint8)
## [Draw the histograms for B, G and R]
## [Normalize the result to ( 0, histImage.rows )]
cv.normalize(b_hist, b_hist, alpha=0, beta=hist_h, norm_type=cv.NORM_MINMAX)
cv.normalize(g_hist, g_hist, alpha=0, beta=hist_h, norm_type=cv.NORM_MINMAX)
cv.normalize(r_hist, r_hist, alpha=0, beta=hist_h, norm_type=cv.NORM_MINMAX)
## [Normalize the result to ( 0, histImage.rows )]
## [Draw for each channel]
for i in range(1, histSize):
cv.line(histImage, ( bin_w*(i-1), hist_h - int(round(b_hist[i-1])) ),
( bin_w*(i), hist_h - int(round(b_hist[i])) ),
( 255, 0, 0), thickness=2)
cv.line(histImage, ( bin_w*(i-1), hist_h - int(round(g_hist[i-1])) ),
( bin_w*(i), hist_h - int(round(g_hist[i])) ),
( 0, 255, 0), thickness=2)
cv.line(histImage, ( bin_w*(i-1), hist_h - int(round(r_hist[i-1])) ),
( bin_w*(i), hist_h - int(round(r_hist[i])) ),
( 0, 0, 255), thickness=2)
## [Draw for each channel]
## [Display]
cv.imshow('Source image', src)
cv.imshow('calcHist Demo', histImage)
cv.waitKey()
## [Display]

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samples/python/tutorial_code/Histograms_Matching/histogram_comparison/compareHist_Demo.py Normal file
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from __future__ import print_function
from __future__ import division
import cv2 as cv
import numpy as np
import argparse
## [Load three images with different environment settings]
parser = argparse.ArgumentParser(description='Code for Histogram Comparison tutorial.')
parser.add_argument('--input1', help='Path to input image 1.')
parser.add_argument('--input2', help='Path to input image 2.')
parser.add_argument('--input3', help='Path to input image 3.')
args = parser.parse_args()
src_base = cv.imread(args.input1)
src_test1 = cv.imread(args.input2)
src_test2 = cv.imread(args.input3)
if src_base is None or src_test1 is None or src_test2 is None:
print('Could not open or find the images!')
exit(0)
## [Load three images with different environment settings]
## [Convert to HSV]
hsv_base = cv.cvtColor(src_base, cv.COLOR_BGR2HSV)
hsv_test1 = cv.cvtColor(src_test1, cv.COLOR_BGR2HSV)
hsv_test2 = cv.cvtColor(src_test2, cv.COLOR_BGR2HSV)
## [Convert to HSV]
## [Convert to HSV half]
hsv_half_down = hsv_base[hsv_base.shape[0]//2:,:]
## [Convert to HSV half]
## [Using 50 bins for hue and 60 for saturation]
h_bins = 50
s_bins = 60
histSize = [h_bins, s_bins]
# hue varies from 0 to 179, saturation from 0 to 255
h_ranges = [0, 180]
s_ranges = [0, 256]
ranges = h_ranges + s_ranges # concat lists
# Use the 0-th and 1-st channels
channels = [0, 1]
## [Using 50 bins for hue and 60 for saturation]
## [Calculate the histograms for the HSV images]
hist_base = cv.calcHist([hsv_base], channels, None, histSize, ranges, accumulate=False)
cv.normalize(hist_base, hist_base, alpha=0, beta=1, norm_type=cv.NORM_MINMAX)
hist_half_down = cv.calcHist([hsv_half_down], channels, None, histSize, ranges, accumulate=False)
cv.normalize(hist_half_down, hist_half_down, alpha=0, beta=1, norm_type=cv.NORM_MINMAX)
hist_test1 = cv.calcHist([hsv_test1], channels, None, histSize, ranges, accumulate=False)
cv.normalize(hist_test1, hist_test1, alpha=0, beta=1, norm_type=cv.NORM_MINMAX)
hist_test2 = cv.calcHist([hsv_test2], channels, None, histSize, ranges, accumulate=False)
cv.normalize(hist_test2, hist_test2, alpha=0, beta=1, norm_type=cv.NORM_MINMAX)
## [Calculate the histograms for the HSV images]
## [Apply the histogram comparison methods]
for compare_method in range(4):
base_base = cv.compareHist(hist_base, hist_base, compare_method)
base_half = cv.compareHist(hist_base, hist_half_down, compare_method)
base_test1 = cv.compareHist(hist_base, hist_test1, compare_method)
base_test2 = cv.compareHist(hist_base, hist_test2, compare_method)
print('Method:', compare_method, 'Perfect, Base-Half, Base-Test(1), Base-Test(2) :',\
base_base, '/', base_half, '/', base_test1, '/', base_test2)
## [Apply the histogram comparison methods]

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samples/python/tutorial_code/Histograms_Matching/histogram_equalization/EqualizeHist_Demo.py Normal file
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from __future__ import print_function
import cv2 as cv
import argparse
## [Load image]
parser = argparse.ArgumentParser(description='Code for Histogram Equalization tutorial.')
parser.add_argument('--input', help='Path to input image.', default='../data/lena.jpg')
args = parser.parse_args()
src = cv.imread(args.input)
if src is None:
print('Could not open or find the image:', args.input)
exit(0)
## [Load image]
## [Convert to grayscale]
src = cv.cvtColor(src, cv.COLOR_BGR2GRAY)
## [Convert to grayscale]
## [Apply Histogram Equalization]
dst = cv.equalizeHist(src);
## [Apply Histogram Equalization]
## [Display results]
cv.imshow('Source image', src)
cv.imshow('Equalized Image', dst)
## [Display results]
## [Wait until user exits the program]
cv.waitKey()
## [Wait until user exits the program]

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samples/python/tutorial_code/ImgTrans/warp_affine/Geometric_Transforms_Demo.py Normal file
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from __future__ import print_function
import cv2 as cv
import numpy as np
import argparse
## [Load the image]
parser = argparse.ArgumentParser(description='Code for Affine Transformations tutorial.')
parser.add_argument('--input', help='Path to input image.', default='../data/lena.jpg')
args = parser.parse_args()
src = cv.imread(args.input)
if src is None:
print('Could not open or find the image:', args.input)
exit(0)
## [Load the image]
## [Set your 3 points to calculate the Affine Transform]
srcTri = np.array( [[0, 0], [src.shape[1] - 1, 0], [0, src.shape[0] - 1]] ).astype(np.float32)
dstTri = np.array( [[0, src.shape[1]*0.33], [src.shape[1]*0.85, src.shape[0]*0.25], [src.shape[1]*0.15, src.shape[0]*0.7]] ).astype(np.float32)
## [Set your 3 points to calculate the Affine Transform]
## [Get the Affine Transform]
warp_mat = cv.getAffineTransform(srcTri, dstTri)
## [Get the Affine Transform]
## [Apply the Affine Transform just found to the src image]
warp_dst = cv.warpAffine(src, warp_mat, (src.shape[1], src.shape[0]))
## [Apply the Affine Transform just found to the src image]
# Rotating the image after Warp
## [Compute a rotation matrix with respect to the center of the image]
center = (warp_dst.shape[1]//2, warp_dst.shape[0]//2)
angle = -50
scale = 0.6
## [Compute a rotation matrix with respect to the center of the image]
## [Get the rotation matrix with the specifications above]
rot_mat = cv.getRotationMatrix2D( center, angle, scale )
## [Get the rotation matrix with the specifications above]
## [Rotate the warped image]
warp_rotate_dst = cv.warpAffine(warp_dst, rot_mat, (warp_dst.shape[1], warp_dst.shape[0]))
## [Rotate the warped image]
## [Show what you got]
cv.imshow('Source image', src)
cv.imshow('Warp', warp_dst)
cv.imshow('Warp + Rotate', warp_rotate_dst)
## [Show what you got]
## [Wait until user exits the program]
cv.waitKey()
## [Wait until user exits the program]