OpenCV二值图求最大连通区域算法（广度优先算法 BFS）

Love The Way You Lie 2021-11-01 14:08 485阅读 0赞

#include <iostream>
    #include <opencv2\opencv.hpp>
    #include <vector>
    #include <opencv2/core.hpp>
    #include <opencv2/highgui.hpp>
    #include <windows.h>
    #include <math.h> 
    #include <queue>
    
    using namespace std;using namespace cv;
    
    #define WHITE 1
    #define GRAY 2
    #define BLACK 3
    #define INFINITE 255
    
    typedef CvPoint ElemType;
    
    typedef struct
    {
        bool vSign;//像素点是否被访问过的标记，ture已访问，false表示未访问,给图片添加的一个属性
        int pixelValue;//像素值
    }isVisit;
    
    typedef struct
    {
        CvPoint regionPoint;//该连通区域起点的坐标
        int regionId;//第i个连通区域的标号
        int pointNum;//第i个连通区域的像素点的总个数
    }connectRegionNumSet;
    
    int calConnectRegionNumsBfs(IplImage *srcGray, vector<vector<isVisit>>& validPicture, vector<connectRegionNumSet> &regionSet);
    
    int main() {
        IplImage * src = cvLoadImage("ff.jpg");
        IplImage * srcGray = NULL;
    
        if (src->nChannels == 1)
            goto next;
        srcGray = cvCreateImage(cvSize(src->width, src->height), 8, 1);
        cvCvtColor(src, srcGray, CV_RGB2GRAY);
        next:
        if (!srcGray)
            cvThreshold(src, srcGray, 66, 255, CV_THRESH_BINARY);
        else
            cvThreshold(srcGray, srcGray, 66, 255, CV_THRESH_BINARY);
        cvNamedWindow("srcBinaryGray");
        cvShowImage("srcBinaryGray", srcGray);
        vector<vector<isVisit> >validPoint;
        validPoint.resize(srcGray->height);
        for (int i = 0; i<validPoint.size(); i++)
            validPoint[i].resize(srcGray->width);
        vector<connectRegionNumSet>regionSet;//存放找到的各个连通区域 regionSet.size()为连通区域的个数。
                                            
        cout << "连通区域的数目：" << calConnectRegionNumsBfs(srcGray, validPoint, regionSet) << endl << endl;//计算连通区域数目
    
        char text[3];//设置连通区域的编号，最小标号为0，最大编号为99
    
        CvFont font;
    
        cvInitFont(&font, CV_FONT_HERSHEY_COMPLEX, 0.6, 0.6, 0, 1, 8);//设置字体//参数从左到右：字体初始化，字体格式，字体宽度，字体高度，字体倾斜度，字体粗细，字体笔画类型
        int max_pointNum = 0; //最大连通区域的像素点个数
        int max_regionId = 0;
        for (int i = 0; i<regionSet.size(); i++)
        {
            cout << "第" << i << "个连通区域的起点坐标 =(" << regionSet[i].regionPoint.x << "," << regionSet[i].regionPoint.y << ")" << ",像素总点数=" << regionSet[i].pointNum << endl;
            cout << "ID:"<<regionSet[i].regionId << endl;
            if (i < 10)
            {
         //连通区域的个数为个位数
                text[0] = '0';
                text[1] = '0' + i;
            }
            else 
            {
         //连通区域的个数为十位数
    
                text[0] = '0' + (i) / 10;
                text[1] = '0' + (i) % 10;
            }
            text[2] = '\0';
            cvPutText(src, text, regionSet[i].regionPoint, &font, cvScalar(0, 0, 255));
            //找到最大连通区域，并标记----------------------------------------------
            if (max_pointNum < regionSet[i].pointNum)
            {
                max_regionId = i;
                max_pointNum = regionSet[i].pointNum;
            }
        }
        cout << "第" << max_regionId << "个连通区域最大" <<"像素总点数=" << regionSet[max_regionId].pointNum << endl;
        cvNamedWindow("src");
        cvShowImage("src", src);
        //cvShowImage("srcGray", srcGray);
        cvWaitKey(0);
        cvReleaseImage(&src);
        cvReleaseImage(&srcGray);
        cvDestroyAllWindows();
    }
    
    int calConnectRegionNumsBfs(IplImage *srcGray, vector<vector<isVisit>>& validPicture, vector<connectRegionNumSet> &regionSet)
    {
        int regionId = 0;//管理连通区域标号的变量
        connectRegionNumSet regionSetTemp;//临时用到的regionSetTemp类型中间变量
        uchar * ptr = (uchar*)(srcGray->imageData);
        for (int y = 0; y < srcGray->height; y++)
        {
         //给图片加上一个是否已访问的属性
            ptr = (uchar*)(srcGray->imageData + y*srcGray->widthStep);
            for (int x = 0; x < srcGray->width; x++)
            {
                validPicture[y][x].pixelValue = (int)ptr[x];
                validPicture[y][x].vSign = false;//开始时默认都未访问
            }
        }
        queue<CvPoint> q;
        CvPoint foundValidPoint;
        for (int y = 0; y < srcGray->height; y++) {
        //给图片加上一个是否已访问的属性
            for (int x = 0; x < srcGray->width; x++) {
                if (validPicture[y][x].pixelValue && !validPicture[y][x].vSign) {
        //找到下一个连通区域的起点,即像素值非零且未被访问过的点
                    int eachRegionAcc = 1;//表示即将要寻找的连通区域的总像素点个数;//将validPicture[y][x]点默认为即将生成的连通区域的起点
                    regionSetTemp.regionPoint = cvPoint(x, y);//x表示列，y表示行
                    regionSetTemp.regionId = regionId++;
                    regionSetTemp.pointNum = 1;
                    regionSet.push_back(regionSetTemp);//将该点设置为已访问，并对其执行入栈操作
                    validPicture[y][x].vSign = true;
                    q.push(cvPoint(x, y));
                    while (!q.empty())
                    {
                        foundValidPoint = q.front();
                        q.pop();
                        int i = foundValidPoint.x;//t
                        int j = foundValidPoint.y;//k
                        int minY = (j - 1 < 0 ? 0 : j - 1);
                        int maxY = ((j + 1 > srcGray->height - 1 ? srcGray->height - 1 : j + 1));
                        int minX = (i - 1 < 0 ? 0 : i - 1);
                        int maxX = (i + 1 > srcGray->width - 1 ? srcGray->width - 1 : i + 1);
                        for (int k = minY; k <= maxY; k++)
                        {
         //在八连通范围内（两点之间距离小于根号2的点）,表示其相邻点,入栈c
                            for (int t = minX; t <= maxX; t++)
                            {
                                if (validPicture[k][t].pixelValue && !validPicture[k][t].vSign)//validPicture[k][t]如果没有访问过
                                {
                                    validPicture[k][t].vSign = true;//标志为已访问，防止死循环
                                    q.push(cvPoint(t, k));
                                    eachRegionAcc++;//相邻点的数目加1                                                        
                                }
                            }
                        }
                    }
                    if (eachRegionAcc > 1) //要求：连通区域的点数至少要有两个
                        regionSet[regionSet.size() - 1].pointNum = eachRegionAcc;
                    else
                    {
         //单个像素点不算，如果单个像素点也算，去掉该else语句即可
                        regionSet.pop_back();//上述默认的即将生成的连通区域不符合要求，出栈
                        regionId--;
                    }
                }
            }
        }
        return regionSet.size();
    }

原图：

![1721907-20190623164903029-995959963.jpg][]

处理之后

![1721907-20190623164915466-1817324713.jpg][]

![1721907-20190623165301794-1752956860.jpg][]

转载于:https://www.cnblogs.com/jxLuTech/p/11072845.html

[1721907-20190623164903029-995959963.jpg]: /images/20211101/37f49b3eb47d46e3a6615e8764462aed.png
[1721907-20190623164915466-1817324713.jpg]: /images/20211101/ca20d01976e949ceb2e48cfdc24d866d.png
[1721907-20190623165301794-1752956860.jpg]: /images/20211101/420d15461cad482489be2d5770959d84.png