mucdev's profile - activity

If there's still no answer on this question, i'll plan to create a JNI-util for all kinds of the same stuffs.

Hi all,

in my application i need to check for intersection and merge the rectangles. In the API of Rect java-class there's some instructions showing how to intersection and merge, as seen:

rect = rect1 & rect2 (rectangle intersection)
rect = rect1 | rect2 (minimum area rectangle containing rect2 and rect3 )

I did try in Eclipse, Java but it's failed:

The operator & is undefined for the argument type(s) org.opencv.core.Rect, org.opencv.core.Rect

Thanks for any help!

Hi Steven,

i wonder how to crop positive samples from a video? The imageclipper tool does not work on video. https://code.google.com/p/imageclipper

Suggestion for other tools is also welcome.

Here is the call to the classifier:

myClassifier.detectMultiScale(mGray, things, 1.2, 3, 2, new Size(minWidth, minHeight), new Size(maxWidth,   maxHeight));

1. I have the same idea, that the partial classifier to operate only around the side-edge.

2. I will try <- some belgian beers should help :)

3. It would be nice if it's possible to manipulate the classifier.xml directly without re-train with the new dataset. I think, it would be somehow possible.

4. I think, the reason, why the object near the image-edge is not always detected, is the minNeighbors param. Sliding windows on multiscale input-image will be applied. The object on the edge will become partial object when the input-image zoomed-in in the next iterattion!!

Hi Steven,

To tackle/detect the partial object, i think, a new classifier with new trainng set is needed, whereas only partial objects used as positive objects.

The problem of training a cascade classifier is the big amount of positive samples. In some papers, they need more than 5000 positive samples. This big number would not easyif possible to achieve manually. There are some tools to help, but you still have to go through all images to draw the bounding boxes

Yesterday night, i did try to test my classifier with different params. The classifier works well on frontal objects. Objects tilting right were also detected. Objects tilting left were not. How can i modify the current classifier.xml file without re-train the classifier, so that those left tilting objects also recognized?

Hi Steven,

According to the way how the training set are created, i.e. each of many positive images is merged into one image with negative background to produce a positive sample. It's also a line in the positve-info.txt file: imgname 1 x y w h.

That way will produce the positive samples with a larger size because of the negative background. The classifier would be then not able to detect the object near the image's edge due to the lack of background information.

I'm not sure if it's right. If yes, no object around the edge could be detected.

My purpose is to detect the objects all around the edge of an image. It would be nice if it's possible.

Hi Steven,

thanks for the respond. Could you please make the 2. point clearer? Especially the way how "to avoid by making bounding boxes"?

Thank you

Hello everybody,

the problem i'm having is to detect the objects on the side as seen in the uploaded Image. The same problem occurs in the sample application "OpenCV face detection". The faces on the side of the camera-frame would not be detected.

Some of those could solve the problem, i think:

1. Train the positive set with smaller size: opencv_createsamples -w -h.
2. Train new positive set to detect "half of the object"

But I'm not experienced with opencv, any suggestion how to fix the problem would be very appreciated!

The problem is, the broken download will also be shown as not-broken. It's shown as an normal full-size .exe file. When people try to open the .exe file, the above error will pop out! In my case, there are 3 downloads of openCV---.exe. Only one of them with the full size has worked!

Your download is not finished. The exe file is broken. Try to download OpenCV from other host!