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103 lines
2.7 KiB
Python
Executable File
103 lines
2.7 KiB
Python
Executable File
#!/usr/bin/python
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from opencv.cv import *
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from opencv.highgui import *
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import sys
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file_name = "../c/baboon.jpg";
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_brightness = 100
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_contrast = 100
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Gbrightness = 100
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Gcontrast = 100
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hist_size = 64
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range_0=[0,256]
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ranges = [ range_0 ]
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src_image=None
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dst_image=None
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hist_image=None
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hist=None
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lut=cvCreateMat(256,1,CV_8U)
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# brightness/contrast callback function
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def update_brightness( val ):
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global Gbrightness # global tag is required, or we get UnboundLocalError
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Gbrightness = val
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update_brightcont( )
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def update_contrast( val ):
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global Gcontrast # global tag is required, or we get UnboundLocalError
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Gcontrast = val
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update_brightcont( )
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def update_brightcont():
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# no global tag required for images ???
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brightness = Gbrightness - 100;
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contrast = Gcontrast - 100;
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max_value = 0;
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# The algorithm is by Werner D. Streidt
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# (http://visca.com/ffactory/archives/5-99/msg00021.html)
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if( contrast > 0 ):
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delta = 127.*contrast/100;
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a = 255./(255. - delta*2);
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b = a*(brightness - delta);
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else:
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delta = -128.*contrast/100;
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a = (256.-delta*2)/255.;
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b = a*brightness + delta;
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for i in range(256):
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v = cvRound(a*i + b);
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if( v < 0 ):
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v = 0;
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if( v > 255 ):
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v = 255;
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lut[i] = v;
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cvLUT( src_image, dst_image, lut );
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cvShowImage( "image", dst_image );
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cvCalcHist( dst_image, hist, 0, None );
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cvZero( dst_image );
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min_value, max_value = cvGetMinMaxHistValue( hist );
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cvScale( hist.bins, hist.bins, float(hist_image.height)/max_value, 0 );
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#cvNormalizeHist( hist, 1000 );
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cvSet( hist_image, cvScalarAll(255));
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bin_w = cvRound(float(hist_image.width)/hist_size);
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for i in range(hist_size):
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cvRectangle( hist_image, cvPoint(i*bin_w, hist_image.height),
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cvPoint((i+1)*bin_w, hist_image.height - cvRound(cvGetReal1D(hist.bins,i))),
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cvScalarAll(0), -1, 8, 0 );
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cvShowImage( "histogram", hist_image );
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if __name__ == "__main__":
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# Load the source image. HighGUI use.
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if len(sys.argv)>1:
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file_name = sys.argv[1]
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src_image = cvLoadImage( file_name, 0 );
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if not src_image:
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print "Image was not loaded.";
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sys.exit(-1)
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dst_image = cvCloneImage(src_image);
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hist_image = cvCreateImage(cvSize(320,200), 8, 1);
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hist = cvCreateHist([hist_size], CV_HIST_ARRAY, ranges, 1);
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cvNamedWindow("image", 0);
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cvNamedWindow("histogram", 0);
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cvCreateTrackbar("brightness", "image", _brightness, 200, update_brightness);
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cvCreateTrackbar("contrast", "image", _contrast, 200, update_contrast);
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update_brightcont();
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cvWaitKey(0);
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