On Nov 16, 2013, at 5:46 PM, Nikos Alexandris <n...@nikosalexandris.net> wrote:
> " Replying to cmbarton: > If you have an image set that is more than 8bit, I can use it to test > some > things. i.histo.match is a nice module. But its objective is different > from > histogram matching in i.pan.sharpen. So it would need modification to > be > used in this context. When I was writing i.pan.sharpen, I looked at the > > i.histo.match code but it was easier to use a much simpler algorithm. > But > since you know i.histo.match maybe you can see where the code could be > > modified to be used in i.pan.sharpen. > > Your histogram matching code matches the histogram of a source image to that > of a target image, whereas i.histo.match matches the histogram of each given > image to the cumulative histogram of all images. Both approaches are valid, > and both should be available in a histogram matching module. " I also looked at i.histo.match when I was writing i.pansharpen. IIRC, its original goal was to create an average histogram that could be applied to multiple images tiled together, so that they would have a nice consistent appearance without patching them into a single image. It is not the kind of histogram matching needed for pan sharpening, however. I do not have an image set that is >8bit and floating point for testing. But someone on the list did not too long ago. Any histogram matching algorithm (including a variant of i.histo.match) could be added as a drop-in method to i.pansharpen. All it needs is to take an "original" and "target" input files (the target is the file whose histogram is modified to match the original), and a "matched" output file. Michael > > >> There I don't see a 8bit limitation (I may be wrong). This might solve >> ticket #2048. > > Note, the IHS method for example depends on the respective modules which are > 8-bit based too if I am not wrong. > > Nikos ____________________ C. Michael Barton Director, Center for Social Dynamics & Complexity Professor of Anthropology, School of Human Evolution & Social Change Arizona State University voice: 480-965-6262 (SHESC), 480-965-8130/727-9746 (CSDC) fax: 480-965-7671 (SHESC), 480-727-0709 (CSDC) www: http://www.public.asu.edu/~cmbarton, http://csdc.asu.edu _______________________________________________ grass-dev mailing list grass-dev@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-dev
