OpenCV连通域数量统计学习示例

/*
	Input:
		src: 待检测连通域的二值化图像
	Output:
		dst: 标记后的图像
		featherList: 连通域特征的清单（可自行查阅文档）
	return：
		连通域数量。
*/
int connectionDetect(Mat &src, Mat &dst, vector<Feather> &featherList)
{
	int rows = src.rows;
	int cols = src.cols;
	int labelValue = 0;
	Point seed, neighbor;
	stack<Point> pointStack;
	// 用于计算连通域的面积
	int area = 0;         
	// 连通域的左边界，即外接最小矩形的左边框，横坐标值，依此类推
	int leftBoundary = 0;       
	int rightBoundary = 0;
	int topBoundary = 0;
	int bottomBoundary = 0;
	// 外接矩形框
	Rect box;                   
	Feather feather;
	vector<stack<Point>> points;
	featherList.clear();
	dst.release();
	dst = src.clone();
	for (int i = 0; i < rows; i++)
	{
		uchar *pRow = dst.ptr<uchar>(i);
		for (int j = 0; j < cols; j++)
		{
			if (pRow[j] == 255)
			{
				area = 0;
				// labelValue最大为254，最小为1.
				labelValue++;       
				// Point（横坐标，纵坐标）
				seed = Point(j, i);     
				dst.at<uchar>(seed) = labelValue;
				pointStack.push(seed);
				area++;
				leftBoundary = seed.x;
				rightBoundary = seed.x;
				topBoundary = seed.y;
				bottomBoundary = seed.y;
				while (!pointStack.empty())
				{
					neighbor = Point(seed.x + 1, seed.y);
					if ((seed.x != (cols - 1)) && (dst.at<uchar>(neighbor) == 255))
					{
						dst.at<uchar>(neighbor) = labelValue;
						pointStack.push(neighbor);
						area++;
						if (rightBoundary < neighbor.x)
							rightBoundary = neighbor.x;
					}
					neighbor = Point(seed.x, seed.y + 1);
					if ((seed.y != (rows - 1)) && (dst.at<uchar>(neighbor) == 255))
					{
						dst.at<uchar>(neighbor) = labelValue;
						pointStack.push(neighbor);
						area++;
						if (bottomBoundary < neighbor.y)
							bottomBoundary = neighbor.y;
					}
					neighbor = Point(seed.x - 1, seed.y);
					if ((seed.x != 0) && (dst.at<uchar>(neighbor) == 255))
					{
						dst.at<uchar>(neighbor) = labelValue;
						pointStack.push(neighbor);
						area++;
						if (leftBoundary > neighbor.x)
							leftBoundary = neighbor.x;
					}
					neighbor = Point(seed.x, seed.y - 1);
					if ((seed.y != 0) && (dst.at<uchar>(neighbor) == 255))
					{
						dst.at<uchar>(neighbor) = labelValue;
						pointStack.push(neighbor);
						area++;
						if (topBoundary > neighbor.y)
							topBoundary = neighbor.y;
					}
					seed = pointStack.top();
					pointStack.pop();
				}
				box = Rect(leftBoundary, topBoundary, rightBoundary - leftBoundary, bottomBoundary - topBoundary);
				feather.area = area;
				feather.boundingbox = box;
				feather.label = labelValue;
				featherList.push_back(feather);
			}
		}
	}
	return labelValue;
}