ASI290 mono software binning issue

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Hs9
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ASI290 mono software binning issue

Post by Hs9 » Fri Nov 18, 2016 3:23 pm

After a few months I recently updated my ZWO ASI drivers. After the update when I use my ASI290 mono camera in SharpCap and select x2 binning the software simply resizes the image with no change to ADU values. Previously I used to see a jump in the ADU values with the whole histogram shifting to the right (which is the correct expected behavior). Is this a change by ZWO?

-Hiten
- Astrojedi

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Sam
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Re: ASI290 mono software binning issue

Post by Sam » Wed Nov 23, 2016 1:39 pm

Hi Hiten
we changed the binning algorithm from sum up to average
so the SNR is still improved but keep the same brightness
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Hs9
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Re: ASI290 mono software binning issue

Post by Hs9 » Thu Nov 24, 2016 4:29 pm

Thanks Sam. Is it possible to have a user selectable option whether to sum or average i.e. provide two different operations? Since formally binning is defined as a sum operation on pixels this will also help avoid confusion with users.

I find the binning operation extremely useful for real time viewing/observing. For imaging I am fine as I make the decision to bin in post processing.
- Astrojedi

riklaunim
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Re: ASI290 mono software binning issue

Post by riklaunim » Thu Nov 24, 2016 5:45 pm

average binning is not always desired or needed. Like methane band imaging.

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Sam
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Re: ASI290 mono software binning issue

Post by Sam » Fri Nov 25, 2016 4:05 am

Hs9 wrote:Thanks Sam. Is it possible to have a user selectable option whether to sum or average i.e. provide two different operations? Since formally binning is defined as a sum operation on pixels this will also help avoid confusion with users.

I find the binning operation extremely useful for real time viewing/observing. For imaging I am fine as I make the decision to bin in post processing.
This make no sense because you can adjust the gain to make image brighter
so sum up = avarage+4x gain
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Hs9
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Re: ASI290 mono software binning issue

Post by Hs9 » Tue Nov 29, 2016 11:55 pm

Sam wrote:
Hs9 wrote:Thanks Sam. Is it possible to have a user selectable option whether to sum or average i.e. provide two different operations? Since formally binning is defined as a sum operation on pixels this will also help avoid confusion with users.

I find the binning operation extremely useful for real time viewing/observing. For imaging I am fine as I make the decision to bin in post processing.
This make no sense because you can adjust the gain to make image brighter
so sum up = avarage+4x gain
Sam,

I think the problem is that these operations (e.g. very high gain) are not mathematically equivalent to binning and can cause other consequences such as calibration issues.

I am already operating at a high enough gain and going beyond it calibration becomes more challenging for me. Binning would provide the sensitivity increase that I am looking for and also the ability to change sampling i.e. arcsecond/pixel which I cannot achieve with averaging. This is also critical for hiding tracking errors or optical aberrations from very high sampling. Averaging does not address this.

Also formally binning is defined as a 'sum' operation of the pixels. You cannot average and then call it binning. It is very confusing when one vendor decides to adopt an arbitrary definition of a formally defined operation in imaging theory.

Further, averaging pixels within the frame is very different to averaging across sub exposures wrt noise reduction as you are comparing one sample to multiple samples which is critical for random noise which varies with time (and from frame to frame). Averaging pixels within the same frame does nothing in this regard as you are averaging samples across the spatial domain and not the time domain. Hence it is a very different operation.

I am quite puzzled as to why there is resistance to fixing this feature. Binning is a very standard operation and should be implemented in line with first principles of imaging. From an effort perspective it should be a very simple change to the driver or am I missing something?

Hiten
- Astrojedi

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Sam
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Re: ASI290 mono software binning issue

Post by Sam » Wed Nov 30, 2016 9:32 am

Hi Hiten
actually, they are the same
because gain more than 300 are digital too
so all are digital processing

we changed the sum up algorithm to avarange is because the digital gain is already high
it's not possible to adjust the brightness value lower when binning at gain 0
and it's too bright when use binning at day time
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easybob95
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Re: ASI290 mono software binning issue

Post by easybob95 » Sat Dec 03, 2016 6:09 pm

Well it is stupid to change sum to average value without asking users !

I do use bin2 for eal time video and I need sum for bin2.

If I want average, I can select hardware bin2 for imx178 camera.

It is really boring you make such changes ! I am very angry with you Sam.

You must restore very quickly sum for software bin2 at least for asi178 color camera.

Alain

Hs9
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Re: ASI290 mono software binning issue

Post by Hs9 » Sun Dec 04, 2016 3:44 pm

Sam wrote:Hi Hiten
actually, they are the same
because gain more than 300 are digital too
so all are digital processing

we changed the sum up algorithm to avarange is because the digital gain is already high
it's not possible to adjust the brightness value lower when binning at gain 0
and it's too bright when use binning at day time
Sam,

I don't want to use digital gain or any other workaround to mimic binning. I want binning (as do most users) and not noise reduction or averaging or any other operation.

If I want to do noise reduction I can use the appropriate filters in software. I would prefer to not be forced to do averaging when I want to do binning.

I am really puzzled as to why you don't want implement binning as binning. Binning is way of managing etendue, averaging is not.

Also I have not purchased this camera to use in the daytime. I want maximum sensitivity for Astro applications.

Hiten
- Astrojedi

chripell
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Re: ASI290 mono software binning issue

Post by chripell » Mon Dec 05, 2016 9:53 pm

Quite frankly I don't understand why so much anger. The only difference between 4*average and sum could be for rounding problems, but I think the digital numbers are already upscaled from the actual ADC dynamic range (12-14 bits) to 16, so there are spare bits that avoid loss of precision when averaging. If this holds true, simply the 2 things are mathematically equivalent, with the advantage of a better utilization of the machine word by averaging. Honestly I would always save unbinned data when possible. I think binning strictly as summation really makes sense in HW much early in the imaging pipeline, so it increases the signal in the SNR, because the noise of following stages remains constant.

This is just my 0.02 eurocent.

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