ipa: rpi: agc: Clamp digital gain to avoid saturation issues#340
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davidplowman wants to merge 1 commit into
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ipa: rpi: agc: Clamp digital gain to avoid saturation issues#340davidplowman wants to merge 1 commit into
davidplowman wants to merge 1 commit into
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Digital gain is used to adjust overall image exposure when the target exposure cannot be achieved (for example, cannot go high enough). But when the target exposure is lower than we can achieve, the digital gain was being set to values less than unity, causing saturation problems. The fix is simply to clamp the digital gain at the bottom to 1.0, resulting in images that, while "too bright", saturate correctly. Fixes: 17f9912 ("ipa: rpi: agc: Calculate digital gain in process()") Signed-off-by: David Plowman <david.plowman@raspberrypi.com> Reviewed-by: Alen Karnil <alen.karnil@ideasonboard.com> Tested-by: Alen Karnil <alen.karnil@ideasonboard.com> Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com> Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
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Looks reasonable. Should we merge? |
Collaborator
Author
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I think so, it's in upstream libcamera already. Also perhaps this one, it's also been merged upstream? |
Collaborator
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Perhaps I should merge the upstream tree in one-shot. Then we can close these. |
Collaborator
Author
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Could do. We might also want to get Nick's fix, for the crash when |
Collaborator
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I don't see a PR for that, but I can add it later. |
Collaborator
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Just running through some tests now on https://github.com/raspberrypi/libcamera/tree/next_merge |
Collaborator
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I've now merged upstream to next, which includes this change. |
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Digital gain is used to adjust overall image exposure when the target exposure cannot be achieved (for example, cannot go high enough). But when the target exposure is lower than we can achieve, the digital gain was being set to values less than unity, causing saturation problems.
The fix is simply to clamp the digital gain at the bottom to 1.0, resulting in images that, while "too bright", saturate correctly.
Fixes: 17f9912 ("ipa: rpi: agc: Calculate digital gain in process()")
Reviewed-by: Alen Karnil alen.karnil@ideasonboard.com
Tested-by: Alen Karnil alen.karnil@ideasonboard.com
Reviewed-by: Kieran Bingham kieran.bingham@ideasonboard.com