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74 lines
1.8 KiB
C++
74 lines
1.8 KiB
C++
/**
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* @file BasicLinearTransformsTrackbar.cpp
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* @brief Simple program to change contrast and brightness
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* @date Mon, June 6, 2011
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* @author OpenCV team
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*/
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#include "opencv2/imgcodecs.hpp"
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#include "opencv2/highgui.hpp"
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// we're NOT "using namespace std;" here, to avoid collisions between the beta variable and std::beta in c++17
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using namespace cv;
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/** Global Variables */
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const int alpha_max = 5;
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const int beta_max = 125;
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int alpha; /**< Simple contrast control */
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int beta; /**< Simple brightness control*/
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/** Matrices to store images */
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Mat image;
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/**
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* @function on_trackbar
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* @brief Called whenever any of alpha or beta changes
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*/
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static void on_trackbar( int, void* )
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{
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Mat new_image = Mat::zeros( image.size(), image.type() );
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for( int y = 0; y < image.rows; y++ )
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for( int x = 0; x < image.cols; x++ )
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for( int c = 0; c < 3; c++ )
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new_image.at<Vec3b>(y,x)[c] = saturate_cast<uchar>( alpha*( image.at<Vec3b>(y,x)[c] ) + beta );
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imshow("New Image", new_image);
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}
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/**
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* @function main
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* @brief Main function
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*/
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int main( int argc, char** argv )
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{
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/// Read image given by user
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String imageName("lena.jpg"); // by default
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if (argc > 1)
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{
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imageName = argv[1];
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}
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image = imread( samples::findFile( imageName ) );
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/// Initialize values
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alpha = 1;
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beta = 0;
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/// Create Windows
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namedWindow("Original Image", 1);
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namedWindow("New Image", 1);
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/// Create Trackbars
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createTrackbar( "Contrast", "New Image", &alpha, alpha_max, on_trackbar );
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createTrackbar( "Brightness", "New Image", &beta, beta_max, on_trackbar );
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/// Show some stuff
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imshow("Original Image", image);
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imshow("New Image", image);
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/// Wait until user press some key
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waitKey();
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return 0;
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}
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