直方图匹配

#include <iostream>
#include <opencv2/opencv.hpp>
using namespace std;
using namespace cv;




uchar* SigResultBandMap = new uchar[256];


void EqualHist(cv::Mat& gray, std::map<int, int>& cnt, std::map<int,  double>& valuePro)
{
	
	//统计像素(0-255)的个数
	for (int i = 0; i < gray.rows; i++)
	{
		//访问元素：
		uchar* ptr = gray.data + i * gray.cols;
		for (int j = 0; j < gray.cols; j++)
		{
			int value = ptr[j];
			cnt[value]++;
		}
	}

	//计算频率,并计算累计频率
	
	int sum = gray.cols * gray.rows;
	double sumPro = 0.0;
	for (int i = 0; i < 256; i++)
	{
		sumPro += ((1.0 * cnt[i]) / sum);
		valuePro[i] = sumPro;
	}

	
}

void minDist(std::map<int, double>& valueProGeo, std::map<int, double>& valueProBase, uchar* SigResultBandMap)
{
	for (int i = 0; i < 256; i++)
	{
		double MinValue = 255;//最小值初始化
		for (int j = 0; j < 256; j++)
		{
			double subValue = fabs(valueProGeo[i] * 255 - valueProBase[j] * 255);
			if (MinValue > subValue)
			{
				MinValue = subValue;
				SigResultBandMap[i] = j;
			}
		}
	}
}


void ReplaceElement(cv::Mat& imageGeo, uchar* SigResultBandMap)
{
	for (int row = 0; row < imageGeo.rows; row++)
	{
		uchar* ptr = imageGeo.data + row * imageGeo.cols;
		for (int col = 0; col < imageGeo.cols; col++)
		{
			ptr[col] = SigResultBandMap[ptr[col]];
 		}
	}
}

int main()
{
	cv::Mat imageGeo = cv::imread("D:/software/image/geo.png");
	cv::Mat imageBase = cv::imread("D:/software/image/base.png");
	cv::Mat imageCopy = imageGeo.clone();

	cv::Mat imageSplitGeo[3];
	cv::Mat imageSplitBase[3];
	cv::split(imageGeo, imageSplitGeo);
	cv::split(imageBase, imageSplitBase);
	

	for (int i = 0; i < 3; i++)
	{
		std::map<int, int>src;
		std::map<int, int>base;

		std::map<int, double> valueProGeo;
		std::map<int, double> valueProBase;

		uchar* SigResultBandMap = new uchar[256];
		//分别对两张图像进行均衡化
		EqualHist(imageSplitGeo[i], src, valueProGeo);
		EqualHist(imageSplitBase[i], base, valueProBase);
		minDist(valueProGeo, valueProBase, SigResultBandMap);
		//替换元素
		ReplaceElement(imageSplitGeo[i], SigResultBandMap);

		delete[] SigResultBandMap;
	}
	//合并图像
	cv::merge(imageSplitGeo, 3, imageGeo);
	return 0;
}