Opencv2.4.9 SimpleBlobDetector掩码不起作用

Opencv2.4.9 SimpleBlobDetector mask does not work

本文关键字：掩码 不起作用 SimpleBlobDetector Opencv2      更新时间：2023-10-16

我已经仔细阅读了这个网站的解释，但无济于事…希望有人知道答案。

我使用simpleBlobDetector来跟踪一些blobs。我想通过检测方法指定一个蒙版，但由于某种原因，蒙版似乎不起作用-我的关键点在整个图像中显示。下面是我的一些代码片段:

Mat currFrame;
Mat mask;
Mat roi;
cv::Ptr<cv::FeatureDetector> blob_detector = new cv::SimpleBlobDetector(params);//custom set of params I've left out for legibility 
blob_detector->create("SimpleBlob");
vector<cv::KeyPoint> myblob;
while(true)
{   
    captured >> currFrame; // get a new frame from camera >> is grab and retrieve in one go, note grab does not allow frame to be modified but edges can be
    // do nothing if frame is empty
    if(currFrame.empty())
    {
        break;
    }
    /******************** make mask***********************/
    mask = Mat::zeros(currFrame.size(),CV_8U);
    roi = Mat(mask,Rect(400,400,400,400));
    roi = 255;
    /******************** image cleanup with some filters*/
    GaussianBlur(currFrame,currFrame, Size(5,5), 1.5, 1.5);
    cv::medianBlur(currFrame,currFrame,3);
    blob_detector->detect(fgMaskMOG,myblob,mask);//fgMaskMOG is currFrame after some filtering and background subtraction
    cv::drawKeypoints(fgMaskMOG,myblob,fgMaskMOG,Scalar::all(-1), DrawMatchesFlags::DRAW_RICH_KEYPOINTS );
    imshow("mogForeground", fgMaskMOG);
    imshow("original", currFrame);
    imshow("mask",mask);
    if(waitKey(1) != -1)
        break;
}

事情是，我确认我的遮罩是正确的使用surfffeaturedetector描述在这里(OpenCV:如何使用遮罩参数特征点检测(SURF))如果有人能看到我的遮罩有什么问题，我真的很感激帮助。不好意思，代码太乱了!

我有同样的问题，找不到解决方案，所以我通过自己检查掩码来解决它:

blob_detector->detect(img, keypoints);
std::vector<cv::KeyPoint> keypoints_in_range;
for (cv::KeyPoint &kp : keypoints)
    if (mask.at<char>(kp.pt) > 0)
         keypoints_in_range.push_back(kp)

我在opencv2.4.8中找到了以下代码:

void SimpleBlobDetector::detectImpl(const cv::Mat& image, std::vector<cv::KeyPoint>& keypoints, const cv::Mat&) const
{
    //TODO: support mask
    keypoints.clear();
    Mat grayscaleImage;

表示这个选项还不被支持。

过滤关键点的解决方案不是很好，因为它很耗时(你必须在整个图像中检测斑点)。

更好的解决方法是在检测前削减ROI，并在检测后移动每个关键点:

int x = 500;
int y = 200;
int width = 700;
int height = 700;
Mat roi = frame(Rect(x,y,width,height));
blob_detector.detect(roi, keypoints);
for (KeyPoint &kp : keypoints)
{
    kp.pt.x +=x;
    kp.pt.y +=y;
}
drawKeypoints(frame, keypoints, frame,Scalar::all(-1), DrawMatchesFlags::DRAW_RICH_KEYPOINTS);
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