binned data and stacking

[spillage]

Hi All,

Whilst my camera is away getting looked at I have been trying to help our a chap from my club with his set up. The issue I have is that I do not bin any of my data with the asi1600 so have very little knowledge about it. But he is wanting to bin the RGB data.

Let say in DSS I want to use a Ha reference frame that has not been binned with the binned R data. I will finally be put into startools but I do know that the images will need to be the same size. Would he have to drizzle the RGB data in DSS?

I will continue on my google quest but thought someone here may more knowledgeable.

Cheers,

[drjolo]

Hello Mark,

CMOS cameras do not support hardware binning, data is effectively binned in the driver layer. The same result you may achieve just by binning in the Maxim or when resize frame to 50%. The only benefit is to have smaller file size. 

For the frame alignment - it depends on software. Some (like PixInsight) handles it well and scales to reference frame. But you can of course drizzle RGB to match bin1 images as well.  

[JamesF]

45 minutes ago, drjolo said:

CMOS cameras do not support hardware binning

Why should that be?  Is there something inherent in the design of CMOS sensors that prevents it?  Or is it just that manufacturers don't see any value in implementing it in hardware?

James

[drjolo]

As far as I know it is about CMOS sensors technology. In CCD sensors read out process is sequential - clock signal moves collected photoelectrons pixel by pixel to output registry, and then to sensor output, when signal is amplified and converted to digital. So by proper clocking it is possible to collect photoelectrons from adjacent pixels into the one and the read signal.

In CMOS each pixel has its own electronics that is responsible for read out process - converting photoelectrons to signal. So the pixel output in CMOS is already a signal, not raw photoelectrons. This way readout process is much faster and read noise is low, but hardware binning is not supported. 

[spillage]

This is why I am struggling to help much as I do not bin. They have a starlight xpress mono which supports binning  I guess I was asking if you can use a non binned reference frame for your binned data in DSS.

[drjolo]

Uh, I read it all wrong - I thought your friend uses ASI1600

For DSS alignment of bin1 and bin2 frames together - unfortunately I do not know

[vlaiv]

Yes, CMOS has different ADC stage than CCD.

CCD moves electrons off chip into ADC, and there you can "add" electrons from multiple cells to a single "well" before ADC.  With CMOS you can't do that, and when binning you are adding already "ADC'd" values - same as in software.

If trying to stack / align already binned CCD data with unbinned - simple thing to do would be to either use software that can align different resolutions, or take your 2xBin data and resize it by factor of 2 prior to stacking / aligning.