Software for binning off-chip?

[opticalpath]

Does anyone know of software that will mathematically 'bin' an image after capture? I want to do some comparisons of images binned 2x2 in the normal way at the time of capture, with similar ones taken at 1x1 and then binned in software later.

All the familiar resizing/ resampling tools will down-scale an image OK, but the super-pixels generated have values that are averaged or interpolated from groups of adjacent pixels. For true binning, adjacent groups of pixels would have to be *added*, not averaged or interpolated. I think it may be possible in PixInsight ..... but I don't have this so have to find another way. Anyone know of an add-in or stand-alone program that would do this kind of pixel maths function?

Thanks

Adrian

[Cath]

Hi Adrian

Averaging and adding is the really the same thing, it's just that the addition is scaled back down to give you a pixel value in the same pixel value range - the average.

[opticalpath]

Hi Cath. I know what you mean, if it was comparing averaging and summing multiple exposures for example, you're right. But in this case there's an important difference: I'm only considering one image, not a sequence, and I want to compare hardware binning with software binning of the pixels in one image. So it really has to be simple addition of groups of four (2x2) or nine (3x3) pixels. Normal resizing or down-sampling routines don't do a simple summing or averaging; they use interpolation methods to try to produce a smooth results, whereas I need a strict addition so it's a valid comparison with hardware binning of the same image. Another thing is that (real) binning can result in some pixels becoming saturated. Software 'binning' by averaging would avoid that. Normally a desirable result, but in this case I need a warts-and-all comparison!

Adrian

[martin_h]

Nebulosity will do it with a variety of options.....

[opticalpath]

Just what I was looking for! Thanks, Martin.

Adrian