opencv2对读书笔记计算图像的直方图

private:
	int histSize[1];//色度变换宽度
	float hranges[2];//像素的最小值及最大值
	const float * ranges[1];//
	int channels[1];//使用的通道
	public:
	 Histogram1D(){
	histSize[0] = 256;
	hranges[0] = 0.0;
	hranges[1] = 255.0;
	ranges[0] = hranges;
	channels[0] = 0;
	 }
	 cv::MatND getHistogram(const cv::Mat &image){
	cv::MatND hist;
	cv::calcHist(&image,1,channels,cv::Mat(),hist,1,histSize,ranges);
	return hist;
	 }

#include 
#include 
#include "cv.h"
#include "highgui.h"
#include 
using namespace std;

class Histogram1D {

private:
	int histSize[1];
	float hranges[2];
	const float* ranges[1];
	int channels[1];

public:
	Histogram1D() {
	histSize[0]= 256;
	hranges[0]= 0.0;
	hranges[1]= 255.0;
	ranges[0]= hranges; 
	channels[0]= 0; 
	}

 cv::MatND getHistogram(const cv::Mat &image) {
	
	cv::MatND hist;

	cv::calcHist(&image, //目标图像
	1,	// 计算一张直方图
	channels,	// 使用的通道数量
	cv::Mat(),	// 图像开关
	hist,	// 返回的直方图
	1,	// 1D直方图
	histSize,	// 色图宽度
	ranges	// 像素值的范围
	);

	return hist;
	}

	cv::Mat getHistogramImage(const cv::Mat &image){

	cv::MatND hist= getHistogram(image);

	double maxVal=0;
	double minVal=0;
	cv::minMaxLoc(hist, &minVal, &maxVal, 0, 0);

	cv::Mat histImg(histSize[0], histSize[0], CV_8U,cv::Scalar(255));

	int hpt = static_cast(0.9*histSize[0]);

	for( int h = 0; h < histSize[0]; h++ ) {

	float binVal = hist.at(h);
	int intensity = static_cast(binVal*hpt/maxVal);
	cv::line(histImg,cv::Point(h,histSize[0]),cv::Point(h,histSize[0]-intensity),cv::Scalar::all(0));
	}
	return histImg;
	}
};

int main()
{
	cv::Mat image= cv::imread("group.jpg",0);
	if (!image.data)
	return 0; 

	cv::namedWindow("Image");
	cv::imshow("Image",image);

	Histogram1D h;

	cv::MatND histo= h.getHistogram(image);

	for (int i=0; i<256; i++) 
	cout << "Value " << i << " = " << histo.at(i) << endl; 

	cv::namedWindow("Histogram");
	cv::imshow("Histogram",h.getHistogramImage(image));

	cv::waitKey();
	return 0;
}