[GRASS-user] Question about i.class

[Ricardo]

Hello.
I am currently using GRASS and want to use the module i.class to
analyze a monochromatic image but it seems that it was not designed to
do so...i am not working with SAT images.
When i try to "analyse" the region i have defined i get the following:

"Warning: prepare_signature: data error..."

I am thinking this can be due to the nature of the image (grey, white &
black) because i am able to classify a color picture.
i.cluster + i.maxlik fail to analyze too, the output is a one colour
(pink) image. 

Any ideas? Is there a way to rewrite the module to improve this
analysis?

Thanks,

Ricardo Oliveira