Track a small object on a rotating fan

[Damingumbc]

Hello:

I want to track a small solid black circle on a rotating fan. The rotating speed is about 30 rpm and the frame rate of the camera is 50 FPS. The first step I want to do is how to identify this circle. I am new to NI IMAQ. Anyone can help me with some suggestions? Thank you very much.

Is it possible to track it in real-time? Like I acquire an image, then process it immediately before the next image is acquired.

[BruceAmmons]

I would think it would be relatively easy.  Once you locate it in one frame, you can limit the search area in the next frame to speed up the process.  Based on the max speed of the fan, you should be able to calculate a search rectangle where the spot should be next.

Since the fan is white and the spot is black, you could probably use binary thresholding to quickly locate the spot.  When the search area is small, pattern matching would probably be fast enough.  You can test some different methods and see how fast they are.

I would use a sequence acquisition to capture 100 images or so, then use them for testing your algorithms.

Bruce

[Damingumbc]

Hello Bruce:

Thank you so much for your reply. I think your method would work. I will try. I think the search area is also changing as the fan is rotating.