OpenCV 直方图程序

开发环境

• VS2008
• OpenCV2.4.3

详细代码

#include "opencv2/highgui/highgui.hpp"
#include "opencv2/imgproc/imgproc.hpp"
#include <iostream>
#include <stdio.h>

using namespace cv;
using namespace std;

int histSize[1];            // number of bins
float hranges[2];            // min and max pixel value
const float* ranges[1];        //
int channels[1];            // only 1 channel used here

void initial()
{
    // Initial arguments for 1D histogram
    histSize[0] = 256;
    hranges[0] = 0.0;
    hranges[1] = 255.0;
    ranges[0] = hranges;
    channels[0] = 0;        // by default, we look at channel 0
}
// Create the 1D histogram
MatND getHistogram(const Mat &image)
{
    MatND hist;
    // Compute histogram
    calcHist(&image, //
        1,             // histogram from 1 image only
        channels,     // the channel used
        Mat(),         // no mask is used
        hist,         // the resulting histogram
        1,             // it is a 1D histogram
        histSize,     // number of bins
        ranges);     // pixel value range
    return hist;
}
Mat getHistogramImage(const Mat &image)
{
    // Compute histogram first
    MatND hist = getHistogram(image);
    // Get min and max values
    double maxVal = 0;
    double minVal = 0;
    minMaxLoc(hist,&minVal,&maxVal,0,0);
    // Image on which to display histogram
    Mat histImg(histSize[0],histSize[0],CV_8U,Scalar(255));
    // Set highest point at 90% of nbins
    int hpt = static_cast<int>(0.9*histSize[0]);
    // Draw a vertical line for each bin
    for (int h=0;h<histSize[0];h++)
    {
        float binVal = hist.at<float>(h);
        int intensity = static_cast<int>(binVal*hpt/maxVal);
        // This function draws a line between 2 points
        line(histImg,Point(h,histSize[0]),Point(h,histSize[0]-intensity),Scalar::all(128));
    }
    return histImg;
}
/** @function main */
int main( int argc, char** argv )
{
    Mat src, dst;
    initial();

    char* source_window = "Source image";
    char* equalized_window = "Equalized Image";

    /// Load image
    src = imread( "lena.jpg", 1 );

    if( !src.data )
    { cout<<"Usage: ./Histogram_Demo "<<endl;
    return -1;}

    /// Convert to grayscale
    cvtColor( src, src, CV_BGR2GRAY );

    /// Apply Histogram Equalization
    equalizeHist( src, dst );


    Mat srcHist = getHistogramImage(src);
    Mat dstHist = getHistogramImage(dst);


    /// Display results
    namedWindow( source_window, CV_WINDOW_AUTOSIZE );
    namedWindow( equalized_window, CV_WINDOW_AUTOSIZE );

    imshow( source_window, src );
    imshow( equalized_window, dst );

    imshow( "Src_Hist", srcHist );
    imshow( "Dst_Hist", dstHist );


    /// Wait until user exits the program
    waitKey(0);

    return 0;
}

程序运行结果