灰度世界算法原理及結合Opencv的C++實現

代碼實現：

int GrayWorld(Mat& src, Mat& dst)
{
	if (src.empty() || src.type()!=CV_8UC3)
		return -1;
	if (dst.empty() || src.type() != dst.type() || src.size() != dst.size())
	{
		dst.create(src.size(), CV_8UC3);
	}
	int nrows = src.rows;
	int ncols = src.cols;
	int jMax = ncols*src.channels();

	double dr = 0.0;
	double dg = 0.0;
	double db = 0.0;

	int i = 0;
	int j = 0;

	for (i = 0; i < nrows; i++)
	{
		uchar* pdate = src.ptr<uchar>(i);
		for (j = 0; j < jMax;)
		{
			db += static_cast<double>(pdate[j++]);
			dg += static_cast<double>(pdate[j++]);
			dr += static_cast<double>(pdate[j++]);
		}
	}
	double dsize = nrows*ncols;
	db = db / dsize;
	dg = dg / dsize;
	dr = dr / dsize;
	double dAvg = db / 3 + dg / 3 + dr / 3;

	db = dAvg / (db+DBL_EPSILON);
	dg = dAvg / (dg + DBL_EPSILON);
	dr = dAvg / (dr + DBL_EPSILON);

	int itemp = 0;
	for (i = 0; i < nrows; i++)
	{
		uchar *pdate = src.ptr<uchar>(i);
		uchar *pdst = dst.ptr<uchar>(i);
		for (j = 0; j < jMax;)
		{
			itemp = static_cast<int>(db*pdate[j]);
			pdst[j] = static_cast<uchar>(itemp > 255 ? 255 : itemp);
			j++;
			itemp = static_cast<int>(dg*pdate[j]);
			pdst[j] = static_cast<uchar>(itemp > 255 ? 255 : itemp);
			j++;
			itemp = static_cast<int>(dr*pdate[j]);
			pdst[j] = static_cast<uchar>(itemp > 255 ? 255 : itemp);
			j++;
		}
	}
	return 0;
}

#include<iostream>
#include <windows.h>
using namespace std;
void testGrayWorld()
{
	Mat src = imread("E:\\AlgorithmImage\\Grayworld.jpg");
	Mat dst;
	int ret = GrayWorld(src, dst);
	if (0 == ret)
	{
		imshow("src", src);
		imshow("dst", dst);
		waitKey(0);
	}
}
int main()
{
	LARGE_INTEGER t1, t2, tc;
	QueryPerformanceFrequency(&tc);
	QueryPerformanceCounter(&t1);
	testGrayWorld();
	QueryPerformanceCounter(&t2);
	printf("Use Time:%f\n", (t2.QuadPart - t1.QuadPart)*1.0 / tc.QuadPart);
	system("pause");
	return 0;
}

**

算法時間：

**
Opencv4.3，VS2015，CPU：AMD
Debug：0.055
Release：0.026

**

效果展示：

**

參考：
http://www.360doc.com/content/16/1021/16/496343_600242849.shtml