Filter noise and interpolate microscopy images in frequency domain

Remove spatial frequencies beyond the optical cutoff and perform physically accurate interpolation.

Intensities recorded by the microscopes (any imaging system with finite aperture) are subject to diffraction limit - the recorded features cannot be finer than the optical cutoff of the system. Filtering the spatial frequencies beyond the optical cutoff provides simple yet effective means of reducing noise. Since microscopy data is band-limited, padding in frequency domain provides accurate interpolation.