[GRASSLIST:2000] Image classification

[Miha STAUT]

Hi,

I have got 485 8-bit TIFF ortophotos that I would like to merge in a unique 
image or maybe 3 to 5 images. The procedure I used was r.in.gdal --> r.patch 
- NO PROBLEM WITH THAT. The problem is that the images are not of a very 
good quality and have very different values for the same land class, i.e. 
some are darker and some lighter + they are shot at different times of the 
day (hilly region). That means the shadows extend differently.

To get a better view of the area I tried to use r.colors col=grey.eq, but 
the edges of the original images are still very visible. Then I thought 
about i.gray.scale. As I understood i.gray.scale changes the values in the 
image. In that way I would manage to get together the images with the values 
much more alike.

But there is no command like that any more. ???

Any better idea? I am not really and expert in image analysis. The aim is to 
transform the images in a way the same values would indicate the same land 
classes. After that get some spectral signatures and try to classify the 
image in a more or less correct way.

If anything is not clear enough, please ask for clarification.

Thanks, Miha Staut

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