Start with MATLAB 7. It has got image processing tools. And it si very easy to learn how to use that. Get one webcam and interface and provess the images with matlab. There are many inbuilt functions in matlab from which u will get a lot of help. ok bye then
If you just need to move the camera with the light .
1-Read the image from memory
2-Apply threshold filter on the image "turn pixels with brithness higher than the threshold into black & pixels with brightness less than threshold into white"
3-calculte the centroide coordinates of the black body in your image
4-with each new frame calculate the new threshold coordinates
5-the diffrance of the two coordinates indicates the direction and distance to move
6-drive a steper motor with no of steps prportional to the distance required