82 lines
2.4 KiB
C++
82 lines
2.4 KiB
C++
/**
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* @function calcHist_Demo.cpp
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* @brief Demo code to use the function calcHist
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* @author
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*/
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#include "opencv2/highgui/highgui.hpp"
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#include "opencv2/imgproc/imgproc.hpp"
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#include <iostream>
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#include <stdio.h>
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using namespace std;
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using namespace cv;
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/**
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* @function main
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*/
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int main( int argc, char** argv )
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{
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Mat src, dst;
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/// Load image
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src = imread( argv[1], 1 );
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if( !src.data )
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{ return -1; }
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/// Separate the image in 3 places ( B, G and R )
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vector<Mat> bgr_planes;
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split( src, bgr_planes );
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/// Establish the number of bins
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int histSize = 256;
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/// Set the ranges ( for B,G,R) )
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float range[] = { 0, 256 } ;
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const float* histRange = { range };
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bool uniform = true; bool accumulate = false;
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Mat b_hist, g_hist, r_hist;
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/// Compute the histograms:
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calcHist( &bgr_planes[0], 1, 0, Mat(), b_hist, 1, &histSize, &histRange, uniform, accumulate );
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calcHist( &bgr_planes[1], 1, 0, Mat(), g_hist, 1, &histSize, &histRange, uniform, accumulate );
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calcHist( &bgr_planes[2], 1, 0, Mat(), r_hist, 1, &histSize, &histRange, uniform, accumulate );
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// Draw the histograms for B, G and R
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int hist_w = 512; int hist_h = 400;
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int bin_w = cvRound( (double) hist_w/histSize );
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Mat histImage( hist_h, hist_w, CV_8UC3, Scalar( 0,0,0) );
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/// Normalize the result to [ 0, histImage.rows ]
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normalize(b_hist, b_hist, 0, histImage.rows, NORM_MINMAX, -1, Mat() );
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normalize(g_hist, g_hist, 0, histImage.rows, NORM_MINMAX, -1, Mat() );
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normalize(r_hist, r_hist, 0, histImage.rows, NORM_MINMAX, -1, Mat() );
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/// Draw for each channel
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for( int i = 1; i < histSize; i++ )
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{
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line( histImage, Point( bin_w*(i-1), hist_h - cvRound(b_hist.at<float>(i-1)) ) ,
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Point( bin_w*(i), hist_h - cvRound(b_hist.at<float>(i)) ),
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Scalar( 255, 0, 0), 2, 8, 0 );
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line( histImage, Point( bin_w*(i-1), hist_h - cvRound(g_hist.at<float>(i-1)) ) ,
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Point( bin_w*(i), hist_h - cvRound(g_hist.at<float>(i)) ),
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Scalar( 0, 255, 0), 2, 8, 0 );
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line( histImage, Point( bin_w*(i-1), hist_h - cvRound(r_hist.at<float>(i-1)) ) ,
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Point( bin_w*(i), hist_h - cvRound(r_hist.at<float>(i)) ),
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Scalar( 0, 0, 255), 2, 8, 0 );
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}
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/// Display
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namedWindow("calcHist Demo", CV_WINDOW_AUTOSIZE );
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imshow("calcHist Demo", histImage );
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waitKey(0);
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return 0;
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}
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