The Reliability of Haar detect object.

asked Oct 22 '13

JHW
1 ●2

updated Oct 22 '13

Hi,

I'm making a program using cvHaarDetectObjects() function.

My question is, can I get the reliability or accuracy of detected objects? (like template matching)

if so, how can I get it?

or can I get a number that indicates the "overlapped detections"?

For example, if I get a 3 objects detected, I want to classify them with the accuracy(or reliability) to find the best from detected object. Also, I want to see the ratio of accuracy(or reliability).

Thanks.

answered Oct 22 '13

Pedro Batista

2213 ●5 ●18 ●42 https://lnkd.in/bw9XGH8

As far as I know, the Cascade Detector method does not return any degree of confidence for positive detections. However, some objects will be detected multiple times on the same image, because of the multiscale feature of the detector.

I think it is safe to assume that the object that is detected the most times will be the most reliable detection.

Comments

Thanks!! I know that cvHaarDetectObjects() gives the object that is most overlapped however, the thing I want to know is "how many times the detected object overlapped" ?! is there any way to get this information?

JHW (Oct 23 '13)edit

I'm not sure if I know what you mean when you talk about overlapped objects, but if it is how many rectangles correspond to the same object, it is possible to get that information.

The method stores the rectangles in a CvMemStorage* storage. You have to check for rectangles that are close to each other and assume that they belong to the same object. Set the minNeighbors parameter to 1, so that the algorithm doesn't group any rectangles together.

Pedro Batista (Oct 23 '13)edit

Thanks ! that's the answer I want to know ! Additionally, "overlapped objects" that I mentioned above means exactly what you have answered, the minNeighbors. Thank you again !

JHW (Oct 23 '13)edit

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