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req better histograms, highlights
Posted: Mon Apr 27, 2009 11:19 pm
by obelisk
I read my camera histogram fine, it shows 0 and 255 values running up the sides of the histogram. But in xnview I can never tell if the values are blown or not, since there seems to be a white margin on the sides.
Also, if I have a dark pic usually the left is miles high, the rest of the histogram is so flat I can't tell anything.
Would be good to see blinking highlights too, as per camera since histograms fail me.
Re: req better histograms, highlights
Posted: Tue Apr 28, 2009 6:30 am
by rra
another improvement would be to (optionally) use a
logarithmic scale for the number of grayscale-values.
Also a cursor which can move around along the (or one of the) histogram-curves
showing the number or percentage of greyscale-values that are present in the image for the selected greyscale
I also have a question:
what exactly is the grayscale filled plot suppose to represent ?
René
Re: req better histograms, highlights
Posted: Wed Apr 29, 2009 1:37 am
by obelisk
gray one is the RGB combined.
Re: req better histograms, highlights
Posted: Wed Apr 29, 2009 10:07 am
by rra
obelisk wrote:gray one is the RGB combined.
Yes, ofcourse, question is what the gray curve is supposed to be,
if it is the luminance then generally the formula:
RGB Luminance value = 0.3 R + 0.59 G + 0.11 B
is used, (see:
http://www.scantips.com/lumin.html )
but that is not at all what I see looking at the histogram of some images.
René
Re: req better histograms, highlights
Posted: Wed Apr 29, 2009 10:40 am
by marsh
The Qt version labels it RGB + Luminance (it looks like same scale as v.1.96)
Re: req better histograms, highlights
Posted: Tue May 05, 2009 10:23 am
by marcoswat
Log scale histograms would be easier to read. Like in camera ones
