Below is a video of the code in action. I had to tweak parameters to the cvHoughCircles() function and the HSV thresholds to prevent false detection.
An important thing to note is that OpenCV's HSV format stores the Hue component as an 8-bit integer in the range of 0-179. This is unlike other graphics software which use Hue values from 0-255.
I observed the following frame rates:
| Resolution | With Hough Circle detection | Without Hough Circle detection |
|---|---|---|
| 320x240 | ~5fps | ~9fps |
| 640x480 | ~2fps | ~4fps |
Based on the benchmark here, I agree with the author that there might be a USB bandwidth limitation that is resulting in low frame rates. I am looking at using the DSP on the board to speed up OpenCV and use a direct interface to a camera to acquire images.
