Importing color-scanned pictures

[Ronald Wiemer]

Hi grass-users,

I have problems importing scanned color-images into grass.
The scannes image is converted into SUN-raster format and then imported
into GRASS4.0, using r.in.sunrast. 
When viewing the picture on a PC, tho colors are nice and
there is hardly any noise in the picture. When I view the picture in
GRASS, the overall shape of elements in the picture is OK, the colors
look like the original ones, but there is a lot of noise, which did not appear
in the original picture, even in colormode float. 
The problem is related to grass, because the
sun raster image is also what it has to be. I've also imported the picture 
with the ppm utilities, the result was as bad as when using r.in.sunrast.
finally I splitted the image in the seperate rgb bands (on a PC) and 
displayed them.
They where perfectly fine. After importing into GRASS, the images where as
noisy as before.  Applying i.colors on these rgb bands, resulted
in the same noisy color picture. What is happening here????. Why is grass not
displaying the original picture?. Someone out there who has experience with
this kind of stuff?.

Thanks for your help.


Ronald Wiemer
Centre of expertise ARCHIS
kerkstraat 1
3811 CV AMersfoort
The Netherlands