I was wondering if the point spread function for thermal imaging is the same that the one which is used for visible imaging. Some authors use different point spread function even in the visible case, so it would be legitim to know what is the best spread function for thermal images.
Thanks
Thermal imaging works in the infrared, which is just light with a longer wavelength than visible light, so there is no difference in the fundamental physics principals at play. The primary factor in the point spread function is going to be the interaction of light with the aperture. If the aperture is round, the Airy function is often used to model it, but sometimes it is approximated by a Gaussian. The wikipedia page for the Airy disk has a good explanation of the relationship between wavelength and the PSF for the case of a point source and a circular aperture.