INDI Library v2.0.2 Released (01 Jun 2023)

Bi-monthly release with minor bug fixes and improvements

FITS Viewer: Histograms

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In the context of another thread I tried to use the FITS viewers histogram mode to analyze the histogram of a dark frame. But (at least IMHO) it is completely useless for that purpose. I wonder if I'm doing something wrong here.

What I want to do is view the histogram of the range 0-500du of a dark frame. I acquire a frame, it's shown in FV, and I activate the histogram. But (probably because of hot pixels etc) with a range 0-40000 or so. I can zoom in, but the resolution doesn't change. I get a pyramid that is zero at 34 and 260 and max at about 148. No way to judge the histogram.
So I change the sliders to show the range 0-500. Or rather, I want to change it. I cannot decrease the low level at all. It sits on 32, if I set it to zero, it jumps back there. I can change the maximum to 500. If I then press 'apply' I get a histogram with 5 peaks (OK, as it is integer data spaced 16 due to the 12-16 bit conversion). But those peaks are at 391, 401, 409, 416 and 423. WTF? And the range slider now shows me 32-37 as limits.
This has absolutely nothing in common with the actual data. Which really make me wonder what that histogram thing is useful for at all :(
openSUSE Tumbleweed KStars git INDI git
GPDX+EQMOD, CEM60EC, ASI2600/1600/290mini+EFW+EAF
2 years 4 months ago #66637

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For next time, post your image data. Was it a FITS or other raw data format?
4 months 3 weeks ago #89508

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