I was experimenting with visual calibration of my desktop CNC by hooking up one of those cheap USB 1000x cameras. I had done some back of the envelope calculat

I was experimenting with visual calibration of my desktop CNC by hooking up one of those cheap USB 1000x cameras. I had done some back of the envelope calculations to figure out that it was about 5 pixels per thousandth of an inch. After a few hours of getting weird inconsistent results, I finally figured out to my shock and horror that the image was drifting and warping by upwards of 20 pixels after the camera had been one for a while (I think it was 640x480 resolution). My friend and I thought this was due to the CCD heating up and warping. It looks like they're using the cooling for noise suppression but I bet the CCD also has the same effect I noticed of 'pixel drift/warp'.