[GRASS-dev] Re: i.rgb.his/i.his.rgb and 16bit images

[Georg Kaspar]

Hamish wrote:
> Very sorry if this is a dumb question, but did you set n_levels= to
> 65535? (it defaults to 8bit)

actually i set it to 2048 but i guess i should have used 2047. the data 
seems to be encoded using 11bits

> Does 'i.rgb2his --help' show the option? what does 'r.info -r' say about
> the 3 r,g,b bands?

yes, the option is shown.

r.info -r on initial datasets 
min=0
max=2047

> really that option name is misleading, it should be max_level=255 or
> n_levels=256 or bitdepth=8. I think to go with bitdepth= with 8,16 as
> the only options. Anyone know if 32bit or other bits satellite/imagery
> data exist?

yes, quickbird seems to use 11bit ;)
but i guess grass will use 16bit to store the data anyway...

> set colors with:
> 
> r.colors band.red color=rules
> 0 black
> 65535 white
> end
> 
> etc.
> 
> note that i.his2rgb has not been modified; experimenting with i.rgb2his
> first.
> 
> do you know of any free-for-download QB data for testing it with?

http://glcf.umiacs.umd.edu/data/quickbird/

bests,
Georg