[GRASS-user] Confused when using i.fusion.brovey

[Nikos Alexandris]

Michael & Co,

I am trying to iron out the hpf fusion implementation before attempting 
to integrate it in i.pansharpen. There is an undesired effect when 
running the i.fusion.hpf script which I don't understand.

It's quite obvious that the algorithm is not uniformly applied through 
out the entire computational region when just when nearing the edges of 
the image(s). It is visible as a thin darker frame (a few pixels wide) 
identified all-around, near the edges of the output image. Especially 
when forcing high modulation factors (to increase sharpness of the final 
product).

I guess that an (r.m)filter expert would probably identify the problem 
quickly. If you zoom in to the example pictures illustrated in 
<https://github.com/NikosAlexandris/i.fusion.hpf/blob/master/Documentation.pdf>, 
or if you simply run it in your own images (just use center=high and 
modulation=max), you can see in the effect in the edges of an output 
(pan-sharpened) image.

Anyone willing to help?

Thanks, Nikos

---
Michael Barton wrote:

>> Nikos,
>> Have you considered adding HPFA Image Fusion Technique as a method 
>> in
>> the i.pan.sharpen module?

Nikos:

> Of course. First, however, I want to complete a stand-alone version.
> Then, check for integration.