Fix Version/s: None
The brighter fatter correction convolves the image with a kernel to do the correction. In the border region of the image where the convolution is not valid there is no correction applied. We need to add a bit in the mask plane to indicate this.
- mentioned in
It was a quick enough thing to do, if SUSPECT is an acceptable mask plane (plus it was a nice break from other tickets).
Do either of you have time to do the quick review?
Thanks for the quick fix!
Some minor code comments on the PR. Beyond that —
- I claim no expertise on the semantics of mask planes, but I wonder if BAD might be better than SUSPECT? I naïvely assume we would simply want to ignore data without BF correction applied, but I would defer to Jim Bosch or Bob Armstrong as to whether I'm right.
- Any chance of adding a test case?
I don't think SUSPECT is quite right (though perhaps it should be repurposed so it could be - right now it really means "high enough that nonlinearity correction may be inaccurate, but not saturated", and we've long thought we should just fix the nonlinearity corrections instead of having it). But I don't necessarily have a better suggestion; BAD means we'll just get rid of those areas entirely (it's what we use for defects). Maybe EDGE, which is what we use for other cases where kernel width means we lose pixels on the outside?
I think the important question is what downstream processing will do with whatever mask bit you choose. My familiarity with those steps w.r.t. mask planes is not what it once was, so I'm afraid I'm not much help there. Yusra AlSayyad or Lauren MacArthur may be in a better position to guess.
Thanks both for your comments.
Christopher Waters — noting you set this to “in progress” — I don't think this is urgent, but if you are free to work on it, then obviously that's great. Unfortunately, I don't know of any list of mask planes beyond what exists in the code; see e.g. DM-2297.