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RESOLVED: analyze TOP Min luminance bug

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RESOLVED: analyze TOP Min luminance bug

Postby lucasm » Tue Jan 08, 2019 11:59 pm

2018.27550 x64 win10

This seems to be an issue with a top in my larger network, so I locked that top and simplified in the attached file.

It seems like the analyze TOP picks up the max value of each channel fine when in max mode, but min mode defaults to -1 across the board.

that said, if I convert the original top to a chop, I can see the values definitely fall below the -1 value.

If I create a top from scratch in a new file a different way, this bug doesn't always re appear, so a little confused about that!

Image

Lucas
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topMin_Bug.1.toe
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Re: analyze TOP Min luminance bug

Postby ben » Tue Jan 22, 2019 7:35 pm

Thanks for the report.
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Re: analyze TOP Min luminance bug

Postby malcolm » Thu Jan 24, 2019 8:52 pm

I don't think this is a bug. The Analyze is outputting the pixel that has the lowest luminance. That is the pixel with (-1, -1, -1). No other pixel creates a lower luminance, since G is 60% of luminance. If you use a reorder to switch R and G channels, then you'll see a different pixel win.
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Re: RESOLVED: analyze TOP Min luminance bug

Postby greg » Sat Jan 26, 2019 1:25 pm

What you expected to see was what I expected to see - the lowest value of red in the image, the lowest value of green, etc just like the default Analyze CHOP does, which treats each channel separately and gives you the minimum for each channel.

The default Analyze TOP takes the luminance of each pixel (a blend of R, G and B) and picks the pixel with the lowest luminance, and outputs the pixel with the lowest luminance. This may not be the pixel with the lowest value in red, for example.

Even the option to use Red instead of Luminance gives you the pixel with the lowest red, but that will not necessarily be the pixel with the lowest green.

We will add the options to give what you expect, but until then, you will have to do 3 Analyze TOPs to get the lowest red, green and blue separately. I'll add a note to the wiki.
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Re: RESOLVED: analyze TOP Min luminance bug

Postby lucasm » Sat Jan 26, 2019 2:52 pm

This makes perfect sense! Thanks for explaining - I mistook what the luminance did technically speaking for what I wanted it to do :roll:

I did notice that I got the correct result on a per channel basis, like red, green etc.
Appreciate the clarification/correction!
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Re: RESOLVED: analyze TOP Min luminance bug

Postby bLackburst » Tue Jan 29, 2019 5:33 am

Some more intelligent dominant colour options for the analyze TOP would be amazing.
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Re: RESOLVED: analyze TOP Min luminance bug

Postby ben » Wed Jan 30, 2019 3:58 pm

This thread's discussion led us to already RFE some new modes. :)
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