直方图均衡与平台直方图

• 统计每一个灰度值的像素点数和所占的百分比
• 累加每一个灰度值的百分比
• 利用新的灰度值的百分比，重新计算每一个灰度值的变化
• 将新的的对应的关系映射到新的图像中

</pre><pre name="code" class="cpp"><span style="white-space:pre">	</span>Mat src,dest;
<span style="white-space:pre">	</span>Src.copyTo(src);

	if (src.channels() > 1)
	{
		cvtColor(src, src, CV_BGR2GRAY);
	}

	MatND  hist;
	const int histSize = 256;
	float range[] = { 0, 255 };
	const float *ranges[] = { range };
	const int channels = 0;
	cv::calcHist(&src, 1, &channels, Mat(), hist, 1, &histSize, ranges);
	float total = src.size().width* src.size().height;
	
	float bins[histSize] = { 0 };
	float binsAcc[histSize] = { 0 };
	Mat lut(1, 256, CV_8U);
	vector<float> vectorBins;
	vector<float> maxBins;
	float sumBins = 0.0;
	int countMax = 0;
	float TValue = 0;
	
	// Find the mapping table
	for (int i = 0; i<histSize; i++)
	{
		float bin_val = hist.at<float>(i); // 第i灰度级上的数
		bins[i] = bin_val / total;

		if (bins[i] > 0)
		{
			vectorBins.push_back(bins[i]);
		}
		
		if (i>0)
		{
			binsAcc[i] =binsAcc[i-1] + bins[i];
		}
		else
		{
			binsAcc[0] = bins[0];
		}
		lut.at<uchar>(i) = static_cast<uchar>(cvRound(binsAcc[i] * 255));
	}

	Mat dest2;
	equalizeHist(src, dest2);
	imshow("equlization2", dest2);

        Mat src,dest;
	Src.copyTo(src);

	if (src.channels() > 1)
	{
		cvtColor(src, src, CV_BGR2GRAY);
	}



	MatND  hist;
	const int histSize = 256;
	float range[] = { 0, 255 };
	const float *ranges[] = { range };
	const int channels = 0;
	cv::calcHist(&src, 1, &channels, Mat(), hist, 1, &histSize, ranges);
	float total = src.size().width* src.size().height;
	
	float bins[histSize] = { 0 };
	float binsAcc[histSize] = { 0 };
	Mat lut(1, 256, CV_8U);
	vector<float> vectorBins;
	vector<float> maxBins;
	float sumBins = 0.0;
	int countMax = 0;
	float TValue = 0;
	
	// Find the mapping table
	for (int i = 0; i<histSize; i++)
	{
		float bin_val = hist.at<float>(i); // 第i灰度级上的数
		bins[i] = bin_val / total;

		if (bins[i] > 0)
		{
			vectorBins.push_back(bins[i]);
		}
		

	}

	// Calculate the Meadin value by 3 sapce
	for (int i = 1; i < vectorBins.size() - 1; i++)
	{
		if (vectorBins[i] < vectorBins[i - 1] && vectorBins[i - 1] < vectorBins[i + 1] || vectorBins[i] > vectorBins[i - 1] && vectorBins[i - 1]  > vectorBins[i + 1])
		{
			vectorBins[i] = vectorBins[i - 1];
		}
		else if (vectorBins[i] < vectorBins[i + 1] && vectorBins[i + 1] < vectorBins[i - 1] || vectorBins[i] > vectorBins[i + 1] && vectorBins[i + 1] > vectorBins[i - 1])
		{
			vectorBins[i] = vectorBins[i + 1];
		}
	}

	// Calculate the max peak value
	for (int i = 1; i < vectorBins.size() - 1; i++)
	{
		if (vectorBins[i] - vectorBins[i - 1] >= 0 && vectorBins[i+1] - vectorBins[i] <= 0)
		{
			maxBins.push_back(vectorBins[i]);
			sumBins += vectorBins[i]; 
			countMax++;
		}
	}

	TValue = sumBins / countMax;


	// Find the mapping table
	for (int i = 0; i<histSize; i++)
	{

		if (bins[i] > TValue)
		{
			bins[i] = TValue;
		}

		if (i>0)
		{
			binsAcc[i] = binsAcc[i - 1] + bins[i];
		}
		else
		{
			binsAcc[0] = bins[0];
		}
	}

	for (int i = 0; i < histSize; i++)
	{
		lut.at<uchar>(i) = static_cast<uchar>(cvRound(binsAcc[i] * 255 / binsAcc[255]));
	}
	
	LUT(src, lut, dest);
	imshow("src", src);
	imshow("equlization", dest);