Pixel binning for smooth high ISO image

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Pixel binning for smooth high ISO image
« on: 09 / December / 2009, 11:51:15 »
Dear All,

As title really. (I have done a search of forum and not found similar topic). Recently I had a play on G9 and noticed that ISO 3200 wasn't as bad (noise wise) as ISO 1600 and realised this was due to compression of image (to smaller size). My sense is this might have been done by pixel binning (although I could be wrong). With that in mind, would CHDK be able to pixel bin a high ISO shot to 640x480 (for example) and produce a butter smooth image(i.e. as at ISO 80)? I have no idea if this is possible but would just like to ask.

Thanks very much,



Offline reyalp

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Re: Pixel binning for smooth high ISO image
« Reply #1 on: 09 / December / 2009, 16:13:26 »
I agree, the ISO3200 modes must do binning or something very similar. This must be done quite early in the pipeline (i.e. in sensor readout like true binning or somewhere shortly after by the Digic DSP), because it's faster than normal shooting. Trying to get the same effect on the main ARM CPU where CHDK runs would be very slow. It's possible that someone could figure out how to control the hardware that does this, but no one has done it yet.

That said, if you just shoot a full resolution image and downscale it to 640x480 on your PC, that will also smooth out a lot of the noise. I'm not sure hardware binning to that resolution would gain you much except speed.
Don't forget what the H stands for.


Offline RaduP

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Re: Pixel binning for smooth high ISO image
« Reply #2 on: 09 / December / 2009, 19:35:02 »
How about being able to save the binning RAW properly? Right now, when saving the RAW the whole RAW buffer is used. Would be nice especially for DNG files.


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