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The Huygens calculator

The Huygens calculator can plot the point-spread function (PSF), the line-spread function (LSF) or the optical transfer function (OTF), as calculated using the Huygens-Fresnel wavelet theory. Following the links in the "See also" section below for detailed instructions.

Brief outline of the Huygens-Fresnel wavelet theory

The goal is to calculate the spot intensity distribution I(x,y) on the image surface taking into account the diffraction of light. The method is to trace a set of rays to the image surface using geometrical optics. The centroid of these rays locates the patch on the surface where we will calculate the intensity distribution. For each ray we set up a spherical wavelet source at the point where the ray intersects the exit pupil. The phase of each wavelet source is determined by the optical path length, along the ray, from the object to the wavelet source. Then, for each point of interest on the image surface, we calculate the wavelet amplitudes at that point. The intensity distribution I(x,y) is given by squared magnitude of the summed amplitudes.

huygens

See also