[GRASS-user] unexpected i.pansharpen results

Nikos Alexandris nik at nikosalexandris.net
Sun Jul 28 16:45:34 PDT 2013

Eric Goddard wrote:

> > I gave up on that pansharpening attempt. I can test some of my imagery
> > tomorrow and let you know if I still have issues with it.

Nikos Alexandris wrote:

> [rest deleted]
> I can't get any decent looking colors, with any of the methods.  I wonder if
> my images are not properly "aligned" or the like. PCA seems to approach it
> right -- the value ranges seem to fit the reflectance scheme (below 1.0)
> but the colors are so fancy... ?
> Will work on it later in the evening.

To-day/-night I got it to work with 11-bit images!  I rescaled them to [0, 
255] and that seems to work just fine.  Even color rebalancing (i.e. of Blue, 
Green and Red fusioned with Pan -IKONOS spectral bands) after the sharpening 
appears acceptable.

A bit skeptical though since the rescaling action throws away some of the 
data's details... :-?

All of my other attempts using out of [0, 255] range values, for example using 
Top-of-Atmosphere Reflectances (floating point values < 1.0)  or  the raw 
IKONOS bands that range between [0, 2047], were not successful.

So, does i.pansharpen expect only 8-bit images?  Can someone confirm or 

Thanks, Nikos

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