The challenge for this week was to create a GUI application that can detect circles from a webcam (preferably in real time).
To do this I had to use the GPU to manipulate the webcam image in a reasonably fast time.
Unfortunately, Java has very little support for running stuff on the GPU and so I decided to use an
OpenCL wrapper called JOCL. My implementation runs just about in real-time, but it would be nice
if I could optimise it a bit more (Edit: was incorrectly clearing the GPU buffers and as such was
losing about 10ms per image).
To detect circles I used the Sobel Operator to create an image that captures the "gradient" of any point. This gradient is then used in a Hough Transform to create a voting space where each pixel "votes" on the most likely space the circle origin would be in. We then extract the highest voted spot and draw a target around it.
As for the webcam I used this very nice module from Bartosz Firyn which works for most webcams. I then just call the animation function every time a new image is given by the webcam. All the GPU code is written in C and is compiled when the program is run.
- CircleDetector which contains the code for running OpenCL code and initialising everything.
- Animation which is run every time the webcam gets a new image and runs the algorithms in CircleDetector.
