opencv学习-imgprocess-直方图

直方图均衡化equalizeHist

#include "opencv2/highgui/highgui.hpp"#include "opencv2/imgproc/imgproc.hpp"#include <iostream>#include <stdio.h>using namespace cv;using namespace std;/** @function main */int main( int argc, char** argv ){Mat src, dst;char* source_window = "Source image";char* equalized_window = "Equalized Image";/// Load imagesrc = imread( argv[1], 1 );if( !src.data ){ cout<<"Usage: ./Histogram_Demo <path_to_image>"<<endl;return -1;}/// Convert to grayscalecvtColor( src, src, CV_BGR2GRAY );/// Apply Histogram EqualizationequalizeHist( src, dst );/// Display resultsnamedWindow( source_window, CV_WINDOW_AUTOSIZE );namedWindow( equalized_window, CV_WINDOW_AUTOSIZE );imshow( source_window, src );imshow( equalized_window, dst );/// Wait until user exits the programwaitKey(0);return 0;}直方图计算1用spilt函数将rgb图像分割成三部分；2 calcHist分别计算各部分直方图；3画出直方图并显示代码如下：#include "opencv2/highgui/highgui.hpp"#include "opencv2/imgproc/imgproc.hpp"#include <iostream>#include <stdio.h>using namespace std;using namespace cv;/*** @function main*/int main( int argc, char** argv ){Mat src, dst;/// Load imagesrc = imread( argv[1], 1 );if( !src.data ){ return -1; }/// Separate the image in 3 places ( B, G and R )vector<Mat> bgr_planes;split( src, bgr_planes );/// Establish the number of binsint 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 Rint 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 channelfor( 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 );}/// DisplaynamedWindow("calcHist Demo", CV_WINDOW_AUTOSIZE );imshow("calcHist Demo", histImage );waitKey(0);return 0;}