the future of histogram - 256 levels not enough

[Bart Coppens]

On Wednesday 17 August 2005 11:47, Casper Boemann wrote:
> yes that is my own resolution, and boudewin, our maintainer uses 1600, but
> none of us feel the need for more than 256. Perhaps 512, but 65K seems a
> magnitude more than 1280, and what with float there the entire image could
> be between 0 and 0.001. Every pixel would then still go into the first bin.
>
> So extending to a greater number of bins seems, to me at least, to be a
> waist. Perhaps you could suggest a way for us to do it.
>
> Looking very much forward to some more input from you.
What would you think about the following. Still have 256 bins, but apply a 
range to it: instead that the 256 bins are scaled so that they fit the entire 
dynamic range, let the user (for colorspaces with > 8 bpp) select which range 
he wants to see in the histogram. So instead of seeing a single bar as a 
histogram when all his values are between 0 and 0.001, a user could say he 
wants the histogram to display only the 0-0.001 range, so he sees a nice 
curvy histogram of that area, fitted to 256 bins.
Of course, this has an obvious drawback: we would need to reiterate over the 
entire image each time the range is changed, resulting in a slow process. 
Also this is probably too advanced for the regular user, but we could hide 
this under an 'Advanced >>' button that would expand the histogram dialog 
when needed.

Bart Coppens