OpenCV Simple Blob Detection

Unity Engine
1

Trying to get the OPenCV for Unity asset to do simple blob detection on a web cam image. The examples all work great - but I can’t get it working on my own. Hoping someone has done some work with this asset and might now the problem.

This is my Update method - the blobDetector has been created in Start like so():

 blobDetector = FeatureDetector.create(FeatureDetector.SIMPLEBLOB);            
            blobDetector.read(Utils.getFilePath("blobparams.yml"));

void Update()
        {
            if (webCamTextureToMatHelper.isPlaying() && webCamTextureToMatHelper.didUpdateThisFrame())
            {
                webCamMat = webCamTextureToMatHelper.GetMat();

                Mat outImgMat = new Mat();

                MatOfKeyPoint keypoints = new MatOfKeyPoint();
              
                blobDetector.detect(webCamMat, keypoints);
               
                Features2d.drawKeypoints(webCamMat, keypoints, outImgMat);
              
                Texture2D texture = new Texture2D(outImgMat.cols(), outImgMat.rows(), TextureFormat.RGBA32, false);

                Utils.matToTexture2D(outImgMat, texture);

                gameObject.GetComponent<Renderer>().material.mainTexture = webCamTextureToMatHelper.GetWebCamTexture();
            }
        }

The problem is that keypoints has a size of 0x0 after the blobDetector.detect runs. I guess it’s not finding any blobs… but it should so I must be doing something wrong.

2

Got it. I had to convert the image from the webcam to grayscale before giving it to the blob detector.

3

Do you have this open source? Or have any problems using the current version of OpenCV for unity?

4

Sorry, but I haven’t used OpenCV / Unity for a while. Is it not working for you?

5

Im trying to use the modern version of OpenCV from the asset store and it does not contain any blob tracking examples just the class BlobTracking

6

hi gamersamer - did you ever get this working - I get an error on the SimpleBlobExample becasue Utils.getFilePath(“blobparams.yml”) returns nothing.

7

oh fixed that. didn’t take the streaming assets folder out into assets doh.