81 lines
1.9 KiB
C++
81 lines
1.9 KiB
C++
#include <opencv2/imgproc/imgproc.hpp>
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#include <opencv2/highgui/highgui.hpp>
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#include <iostream>
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using namespace cv;
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using namespace std;
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int _brightness = 100;
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int _contrast = 100;
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Mat image;
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/* brightness/contrast callback function */
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void updateBrightnessContrast( int arg, void* )
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{
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int histSize = 64;
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int brightness = _brightness - 100;
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int contrast = _contrast - 100;
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/*
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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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*/
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double a, b;
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if( contrast > 0 )
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{
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double 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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}
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else
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{
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double 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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}
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Mat dst, hist;
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image.convertTo(dst, CV_8U, a, b);
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imshow("image", dst);
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calcHist(&dst, 1, 0, Mat(), hist, 1, &histSize, 0);
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Mat histImage = Mat::ones(200, 320, CV_8U)*255;
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normalize(hist, hist, 0, histImage.rows, CV_MINMAX, CV_32F);
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histImage = Scalar::all(255);
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int binW = cvRound((double)histImage.cols/histSize);
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for( int i = 0; i < histSize; i++ )
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rectangle( histImage, Point(i*binW, histImage.rows),
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Point((i+1)*binW, histImage.rows - cvRound(hist.at<float>(i))),
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Scalar::all(0), -1, 8, 0 );
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imshow("histogram", histImage);
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}
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int main( int argc, char** argv )
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{
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// Load the source image. HighGUI use.
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image = imread( argc == 2 ? argv[1] : "baboon.jpg", 0 );
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if( image.empty() )
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{
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cout << "Image was not loaded.\n";
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return -1;
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}
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namedWindow("image", 0);
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namedWindow("histogram", 0);
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createTrackbar("brightness", "image", &_brightness, 200, updateBrightnessContrast);
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createTrackbar("contrast", "image", &_contrast, 200, updateBrightnessContrast);
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updateBrightnessContrast(0, 0);
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waitKey();
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return 0;
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}
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