Hi,
I'm trying to build similar scanning IR-camera as your camera. I'm wondering if you have tried reading the chip also with PWM, to test if it would be faster ? As I read from the data-sheets, default output is PWM on the range of -20 - 120 C. As I don't yet have actual chip, I can't verify the code above. But as I get the chip (MLX90614ESF-BCF from Future Electronics), I'll try to reproduce the project and test the response time.
Another speedup would be to highlight the "interesting areas" from the web-cam picture before taking actual temperature-measurements. That way the area that needs to be scanned with the sensor would be much smaller - at least if there are only few interesting areas in the whole picture. That would be useful when scanning for wiring, connectors, IC-chips etc. Lot's of background that could be scanned only with limited resolution / faster and then focus on the most important areas in the picture.
But this all is still theory until they deliver my chip - hopefully soon.
With best regards from Finland,
Henkka