tool tips for 1.7

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alacant
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Joined: Mon Jan 25, 2016 7:03 am

Re: tool tips for 1.7

Post by alacant »

1.7.456
Hi Ivo, everyone

module: Deconvolution

Error Diffusion. The help (?) refers to 'Regularization' with a default value of 1.0, but the field is entitled, 'Error Diffusion', with a %slider.

What is it?

Cheers and clear skies,
Steve
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Re: tool tips for 1.7

Post by admin »

alacant wrote: Tue Dec 29, 2020 5:13 pm 1.7.456
Hi Ivo, everyone

module: Deconvolution

Error Diffusion. The help (?) refers to 'Regularization' with a default value of 1.0, but the field is entitled, 'Error Diffusion', with a %slider.

What is it?

Cheers and clear skies,
Steve
Hi Steve,

Thanks for reporting this one. I just updated the 1.7.456 'resources' file (it didn't warrant a recompile) with the correct documentation.
If there were any doubt about what it does (from the docs);
Understanding regularization
Image
^ Left: No deconvolution. 2nd left: "ideal" stable solution. Middle: Moderate error diffusion. 2nd right: Aggresive error diffusion. Right: Unstable (too high Error Diffusion). Notice that at 100% zoom, the intelligent error diffusion is barely noticeble, however introduces subtly more detail and tighter stars (middle).

Deconvolution is exceptionally sensitive to noise; without something discerning between newly recovered detail and artefact, the compounding effect of multiple iterations of deconvolving noise will quickly end up in a noisy, artefacting mess. The process that discerns between artefact and detail is regularization.
Image
^ At 200% zoom, the error diffusion is revealed as a subtle noise/dithering pattern around the enhanced detail (middle), breaking the pyschovisual effect.

Psychovisual trickery


A further innovation in StarTools' deconvolution algorithm, is its ability to tightly control destabilisation. It is possible to artificially limit StarTools' default advanced regularization stabilisation behaviour, by increasing the 'Error Diffusion' parameter from 0%. This will cause the deconvolution algorithm to cleverly exploit a quirk of the human visual system, which makes it so that noise in areas of high detail are harder to discern. By allowing the solution to destabilise only in those areas, more perceptual detail can be eeked out, without causing destabilisation to become noticeable. It should be noted that at zoom levels higher than 100%, the illusion falls apart, and the human eye will start detecting the diffused grain for what it is; destabilisation artefacts.
Cheers!
Ivo Jager
StarTools creator and astronomy enthusiast
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