128 lines
3.1 KiB
C
128 lines
3.1 KiB
C
#ifdef _CH_
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#pragma package <opencv>
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#endif
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#define CV_NO_BACKWARD_COMPATIBILITY
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#ifndef _EiC
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#include "cv.h"
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#include "highgui.h"
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#include <stdio.h>
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#endif
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char file_name[] = "baboon.jpg";
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int _brightness = 100;
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int _contrast = 100;
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int hist_size = 64;
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float range_0[]={0,256};
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float* ranges[] = { range_0 };
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IplImage *src_image = 0, *dst_image = 0, *hist_image = 0;
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CvHistogram *hist;
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uchar lut[256];
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CvMat* lut_mat;
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/* brightness/contrast callback function */
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void update_brightcont( int arg )
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{
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int brightness = _brightness - 100;
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int contrast = _contrast - 100;
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int i, bin_w;
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float max_value = 0;
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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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if( contrast > 0 )
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{
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double delta = 127.*contrast/100;
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double a = 255./(255. - delta*2);
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double b = a*(brightness - delta);
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for( i = 0; i < 256; i++ )
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{
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int 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] = (uchar)v;
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}
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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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double a = (256.-delta*2)/255.;
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double b = a*brightness + delta;
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for( i = 0; i < 256; i++ )
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{
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int 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] = (uchar)v;
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}
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}
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cvLUT( src_image, dst_image, lut_mat );
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cvShowImage( "image", dst_image );
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cvCalcHist( &dst_image, hist, 0, NULL );
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cvZero( dst_image );
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cvGetMinMaxHistValue( hist, 0, &max_value, 0, 0 );
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cvScale( hist->bins, hist->bins, ((double)hist_image->height)/max_value, 0 );
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/*cvNormalizeHist( hist, 1000 );*/
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cvSet( hist_image, cvScalarAll(255), 0 );
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bin_w = cvRound((double)hist_image->width/hist_size);
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for( i = 0; i < hist_size; i++ )
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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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}
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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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src_image = cvLoadImage( argc == 2 ? argv[1] : file_name, 0 );
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if( !src_image )
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{
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printf("Image was not loaded.\n");
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return -1;
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}
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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(1, &hist_size, CV_HIST_ARRAY, ranges, 1);
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lut_mat = cvCreateMatHeader( 1, 256, CV_8UC1 );
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cvSetData( lut_mat, lut, 0 );
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cvNamedWindow("image", 0);
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cvNamedWindow("histogram", 0);
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cvCreateTrackbar("brightness", "image", &_brightness, 200, update_brightcont);
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cvCreateTrackbar("contrast", "image", &_contrast, 200, update_brightcont);
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update_brightcont(0);
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cvWaitKey(0);
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cvReleaseImage(&src_image);
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cvReleaseImage(&dst_image);
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cvReleaseHist(&hist);
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return 0;
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}
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#ifdef _EiC
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main(1,"demhist.c");
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#endif
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