Software binning 2x2

rdryfoos

Well-known member
What is the correct way to software bin 2x2 in Pixinsight.  Is it the integer sampling tool, or the resampling tool?  I am using a CMOS sensor that does not support hardware binning.
Thnaks,
Rodd
 
Hi Rodd,

You should use IntegerResample in this case. Resample will interpolate your data using variable size convolution kernels, which is not what you want to simulate binning.
 
I see only 'average, median, max, min' as options for IntegerResample, to simulate binning I expected 'sum' to also be an option.
 
Hi all,
can i just revisit this?

i am likely among a growing number of folk trying to use scmos cameras where i have to software bin.

i tried integer resample as follows:
i took an image from my cos camera - it has 60mp so needs binning.
i made a duplicate of the image for comparison purposes
i plate solved the images which yielded the same results
i asked integer resample to downsample 2x one of the images - so now i have a 2x binned and an unbinned image
i wanted to see the SNR impact and was unsure how best to , but used the aperture photometry script as it throws off SNR info on brightest stars....
i used an aperture of 2x for the unbinned data versus that for the binned data with larger and fewer pixels.

i was hoping that my binned image would see an increase in SNR by a good amount but shy of 2x....
however...the binned image had almost exactly half the SNR of the unbinned image and attach a screenshot of the 2 situations, "nobin" with photometry aperture of 16 and "binned" with aperture of 8.

my understanding was that we would add the signal from the 4 pixels and add [square root of 4=2] times the noise via binning and so see the SNR go up. it looks like we averaged the signal and added the noise so causing SNR to go down

would be very grateful if some one could point out the error of my ways here and/or advise how i can get the desired increase in SNR from binning using integerresample.

thanks
gavin
 

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Hello,
no explanation were found about the cause of Gavin SNR going down when « integer resampling » ?
thanks
pierre
 
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