连通域查找【未完】

参考：

https://blog.csdn.net/qq_37059483/article/details/78018539

https://blog.csdn.net/xjt2015/article/details/51283387

http://www.cnblogs.com/ronny/p/img_aly_01.html

http://www.cnblogs.com/tiandsp/archive/2012/12/06/2805276.html

#include <opencv2opencv.hpp>
#include <iostream>
#include <vector>
#include <stack>
using namespace std;
using namespace cv;

typedef struct _Feather
{
    int label;              // 连通域的label值
    int area;               // 连通域的面积
    Rect boundingbox;       // 连通域的外接矩形框
} Feather;

/*
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
return：
连通域数量。
*/
int bwLabel(Mat & src, Mat & dst, vector<Feather> & featherList)
{
    int rows = src.rows;
    int cols = src.cols;

    int labelValue = 0;
    Point seed, neighbor;
    stack<Point> pointStack;    // 堆栈

    int area = 0;               // 用于计算连通域的面积

    int leftBoundary = 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 rightBoundary = 0;
    int topBoundary = 0;
    int bottomBoundary = 0;
    Rect box;                   // 外接矩形框
    Feather feather;

    featherList.clear();    // 清除数组

    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++)
        {
            //【注：一旦连通域赋值为1；遍历当前行的下一行时候，就会自动跳过下面if判断】
            if (pRow[j] == 255)
            {
                area = 0;
                labelValue++;           // labelValue最大为254，最小为1.
                seed = Point(j, i); //（731，49）    // Point（横坐标，纵坐标）(x,y)
                                    //int p = dst.ptr<uchar>(i)[j];
                dst.at<uchar>(seed) = labelValue;//1
                pointStack.push(seed);//坐标压栈

                area++;
                leftBoundary = seed.x;//731
                rightBoundary = seed.x;//731
                topBoundary = seed.y;//49
                bottomBoundary = seed.y;//49

                while (!pointStack.empty())
                {
                    //<1>右邻像素点
                    neighbor = Point(seed.x + 1, seed.y);
                    if ((seed.x != (cols - 1)) && (dst.at<uchar>(neighbor) == 255))
                    {
                        dst.at<uchar>(neighbor) = labelValue;//【注：】赋值便签1，保证不走回头路和分类连通域
                        pointStack.push(neighbor);

                        area++;
                        if (rightBoundary < neighbor.x)//更新边界
                            rightBoundary = neighbor.x;
                    }
                    //<2>下邻像素点
                    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;

                    }
                    //<3>左邻像素点
                    neighbor = Point(seed.x - 1, seed.y);
                    //int testx = seed.x;
                    //int testp = dst.at<uchar>(neighbor);
                    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;
                    }
                    //<4>上邻边界点
                    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);
                rectangle(src, box, 255);
                feather.area = area;
                feather.boundingbox = box;
                feather.label = labelValue;
                featherList.push_back(feather);
            }
        }
    }
    return labelValue;
}

int main(int argc, char *argv[])
{
    Mat src(imread("test3.jpg", 0));
    if (src.empty())
        exit(-1);
    threshold(src, src, 127, 255, THRESH_BINARY);   // 二值化图像
    vector<Feather> featherList;                    // 存放连通域特征
    Mat dst;
    cout << "连通域数量： " << bwLabel(src, dst, featherList) << endl;

    // 为了方便观察，可以将label“放大”
    for (int i = 0; i < dst.rows; i++)
    {
        uchar *p = dst.ptr<uchar>(i);
        for (int j = 0; j < dst.cols; j++)
        {
            p[j] = 30 * p[j];
        }
    }

    cout << "标号" << "	" << "面积" << endl;
    for (vector<Feather>::iterator it = featherList.begin(); it < featherList.end(); it++)
    {
        cout << it->label << "	" << it->area << endl;
        rectangle(dst, it->boundingbox, 255);
    }
    cv::namedWindow("dst", WINDOW_NORMAL);
    imshow("src", src);
    imshow("dst", dst);

    waitKey();
    destroyAllWindows();

    system("pause");
    return 0;
}