Filter Capture by Quality Estimator

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Borodog
Posts: 330
Joined: Fri Jan 01, 2021 7:25 pm

Filter Capture by Quality Estimator

#1

Post by Borodog »

I am not certain that this feature is feasible, but it would certainly be nice to have if it were.

I would like to be able to filter out, i.e. not record, frames during capture that fall below a user selected cutoff of an Autostakkert-esque "Quality Estimator" metric. This could reduce file sizes for captures and subsequent processing time downstream in Autostakkert.

The user could put SharpCap into a "monitor" mode where it would accumulate quality statistics and present a running histogram of quality. The user could then enter an absolute quality value as the cutoff before capture. SharpCap already does something like this with the various focus aids, the seeing monitor, filtering by FWHM in live stacking, etc.

The drawback then is that the quality metric would need to be calculated on the fly during capture. It is unclear whether any given computer could keep up with the frame rate for any given camera and ROI, or if the frame rate would suffer in order to estimate the quality from each frame. The quality estimation workload could be reduced in the way that Autostakkert bins for different SNR data; it bins the data NxN, where N may be 2 - 8, before quality estimation. This is done to enhance the SNR, but it also reduces the workload substantially. In my experience N = 6 is virtually always a good choice. If the frame rate would suffer then this is probably not a good idea for planetary or solar imaging. But for lunar imaging (my primary intended use of this feature), we don't really care about frame rate much.

Thanks for your consideration.
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admin
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Re: Filter Capture by Quality Estimator

#2

Post by admin »

Hi,

if you are looking for this for lunar/solar/planetary video capture, then the feature already exists - it's called 'Seeing Filtered Capture', and basically only saves the frames that meet a certain quality threshold in terms of measured frame contrast. The documentation on the seeing monitor functionality is here : https://docs.sharpcap.co.uk/4.0/#!2!Seeing%20Monitor

cheers,

Robin
Borodog
Posts: 330
Joined: Fri Jan 01, 2021 7:25 pm

Re: Filter Capture by Quality Estimator

#3

Post by Borodog »

Well look at that! I will give it a look. Thank you very much!
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