[ImageJ-devel] ROI -> Overlay bug

Michael Doube michael at doube.net
Sun May 13 16:24:43 CDT 2012


> in Fiji
> we consider pixel coordinates at a pixel's center which is in perfect
> agreement when working with microscopic images (particularly confocal
> scanners where the coordinate really is a point sample

It's not really - the scanned point is normally moving for the duration
of sampling, so there is some lateral smear of the sampled space. In
many confocals the scan speed varies within a row, so the 'point
samples' aren't  even the same on that level. True point-by-point
scanning requires the scan mechanism to dwell for the duration of
measurement, then not measure while the mechanism moves to the next
dwell point. As far as I'm aware this is not implemented in current
'point-scanners' because it would be horribly slow to stop and start the
scan mirrors millions of times per frame.

Michael




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