Processing of a Moon image with the Vancittert method

Image processing by vancittert (deconvolution algorithm) is a little more complicated than wavelet because it is less interactive. Indeed, it runs only via the command box of Iris. The command is "vancittert".

Syntax: vancittert [fwhm] [number of iterations]

The parameter [number of iterations] gives the number of iterations to be performed (typically between 5 & 20), whereas [fwhm] is the characteristic FWHM of the stars in the image to restore. More practically, this last parameter determines the strength of processing by the vancittert method.

For example:

>vancittert 3 7

You might have to try several different values for strength of processing before getting a good image. You can also write or use an existent script (see this page) to process your image with various parameters and then choose the one you prefer. It's also easy to add wavelets to an image already processed with the vancittert method. All is a matter of personal preference and I think that processing by wavelets degrades the details on the Moon. I prefer a mix of vancittert and wavelets. In any case, take care with the strength of the processing: there is no point going too far. Often, it is necessary to conduct several tests before achieving something good.

Here are 4 images of a video of Tycho (made by Rolf Arcan) processed by vancittert and/or wavelets. It is likely that two different people vote for 2 different images...

Processing with vancittert and wavelets - by Sebastien Leboutte Processing with wavelets - by Sebastien Leboutte
Processing with wavelets - by Rolf Arcan Processing with vancittert - by Sebastien Leboutte

2018 Leboutte Sebastien - -