Write a simple device driver or callback resident program for Linux / Android

We have a web cam that we would like to function like a mouse. By using the brightest spots on the screen we can tell where the Webcam is pointing. We want this to run on Android so the most logical method seems to be a device driver (Mouse or similar pointing device). There may well be other simpler options available. What we would like is something like the following. module_init -> Set up the webcam using v4l2 API set up two streaming buffers. On Buffer full it should simply scan the Display buffer looking for the two brightest spots (of at least MIN_X and MIN_Y size). The returned average of these two bright spot co-ordinates are the mouse pointer co-ordinates.