Severe contrast enhancements: on 45% rule — and cats

Started Jun 28, 2013 | Discussions thread
ilza
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Re: Changing contrast without distorting colors: 45% rule and another cat
In reply to Tom Axford, Jul 12, 2013

Tom Axford wrote:

I hope you will not be offended by a little personal advice: it does not encourage readers to take your work seriously when you are so dismissive about the work of others.

I have had a look at the paper you referenced and there is one short paragraph about handling saturation. They state that the method they use is essentially the same as previous researchers have used. Clearly their paper is primarily about their HDR method for transforming luminance and they have just picked up whatever was to hand to handle the colour.

This exactly MY point.  These people must be very competent, and thorough.  They must have investigated the subject, and picked the best way known.  And this way stinks.

If I understand their maths correctly, what they do to the saturation is simply take a percentage of the original saturation (arrived at by trial and error).

Yes, and they mutilate the saturation even in the parts of the image where contrast has not been changed!  And did not you notice that they manipulate the hue too — again, even where the brightness was not touched by their algorithm.

Do you still think that I’m “dismissive”?

Ilya

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