[GRASSLIST:7608] Re: color balancing in mosaic

[Feng Tan]

Hi, Hamish,

Thanks for give me ideas! I use i.fusion.brovey to sharppen the image to 15m 
resolution first, then adjust the color from brovey's RGB channels according 
a reference image in the mosaic. I am trying your idea, but it doesn't work 
very well, at least it does not process automatically. It is hard to choose 
the proper min, max  from histogram. Maybe I should do more testing. Any more 
suggestion? 

Feng 



On Sunday 17 July 2005 20:36, you wrote:
> > Thank you very much for your reply!! Yes, I only use the mosaiced
> > images for  "good looking" not for classification purpose. (I know it
> > takes raw image for  classification, so we don't change their spectral
> > information, thanks for  remind me this!). I believe you have ideas
> > how to color balancing for my  mosaiced, color composited landsat
> > images for viewing.
>
> I am no RS expert, but for nice looking LANDSAT output here are some
> things you might try.
>
> Use d.histogram to do a subjective or r.stats to do an objective
> analysis of each band's distribution. Rescale with r.rescale or
> r.rescale.eq (?) and gate filter back to (0,255) with r.mapcalc.
> Or try r.univar and resample to +/- 1.5 stdev's from the mean or
> whatever is appropriate.
>
>
> Then use i.oif to see which combination of three bands show the most
> information and try displaying different RGB combinations of those three
> bands with d.rgb & see what looks good.
>
>
>
> Hamish