OpenCV C++ 简单小技巧 - 视频分析 (23

跟踪对象 meashift

long frameTotal = capture.get(CV_CAP_PROP_FRAME_COUNT);
if (!capture.isOpened()) {
    return;
}
capture.set(CV_CAP_PROP_POS_FRAMES, 30);
double frameRate = capture.get(CV_CAP_PROP_FPS);
bool isLoopFirst = true;

//视频中要跟踪的区域
cv::Rect rectTarget(310, 494, 47, 52);
Mat roi,hsv_roi,mask;
MatND roi_hist;
TermCriteria term_crit(TermCriteria::EPS|TermCriteria::COUNT,10,1);

vector imagesNum = {1};
int histSize = 255;
float ranges[] = { 0, 180 };
const float* histRange = { ranges };
int channels[] = {0,1,2};

while (true) {
    if (!capture.read(frame)) {
        break;
    }
    Mat M = getRotationMatrix2D(Point2f(frame.cols/2,frame.rows/2),90,1);
    warpAffine(frame,frame,M,frame.size());
    
    if(isLoopFirst){
        isLoopFirst = false;
        frame(rectTarget).copyTo(roi);
        cvtColor(frame, hsv_roi, CV_BGR2HSV);
        vector lowPass = {0,60,32};
        vector highPass = {180,255,255};
        inRange(hsv_roi, lowPass, highPass, mask);
        calcHist(&hsv_roi, 1, channels, mask, roi_hist, 1, &histSize, &histRange);
        normalize(roi_hist, roi_hist, 255, 0, NORM_MINMAX);
    }else{
        Mat hsv;
        cvtColor(frame, hsv, CV_BGR2HSV);
        Mat dst;
        calcBackProject(&hsv,1, channels, roi_hist, dst, &histRange);
        RotatedRect rr = CamShift(dst, rectTarget, term_crit);
        Mat pts2f,ptsCov;
        boxPoints(rr, pts2f);
        pts2f.assignTo(ptsCov,CV_32S);
        polylines(frame, ptsCov, true, Scalar(255),5);
    }
    cvtColor(frame, frame, CV_BGR2RGB);
    //这里写刷新ui代码
    usleep(0.05*1000000);
}

这里我跟踪的对象不正确，变成了暗色的山，本来跟踪的是黄色衣服

camshift 跟踪

将meanshift算法扩展到连续图像序列，就是camshift算法。它将视频的所有帧做meanshift运算，并将上一帧的结果，即搜索窗的大小和中心，作为下一帧meanshift算法搜索窗的初始值。如此迭代下去，就可以实现对目标的跟踪

https://blog.csdn.net/dcrmg/article/details/52771372
https://blog.csdn.net/leixiaohua1020/article/details/12236091

image.png