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