>Psychtoolbox>PsychOptics

mtf = DiffractionMTF(s,pupil,nm)

Compute the diffraction-limited MTF
for incoherent light.

s = spatial frequency in c/deg  
pupil = pupil diameter in mm  
nm = wavelength in nm  

Goodman, J. W. (1968) Introduction to Fourier Optics.
San Francisco: McGraw-Hill.