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

GRASS GRASS user
,
1

Nikos,

Nikos,

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

Michael

C. Michael Barton
Director, Center for Social Dynamics & Complexity
Professor of Anthropology, School of Human Evolution & Social Change
Head, Graduate Faculty in Complex Adaptive Systems Science
Arizona State University

voice: 480-965-6262 (SHESC), 480-965-8130/727-9746 (CSDC)
fax: 480-965-7671 (SHESC), 480-727-0709 (CSDC)

www: http://www.public.asu.edu/~cmbarton, http://csdc.asu.edu

On Nov 4, 2014, at 8:00 AM, <grass-user-request@lists.osgeo.org> <grass-user-request@lists.osgeo.org> wrote:

From: Nikos Alexandris <nik@nikosalexandris.net>

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

Date: November 4, 2014 at 3:28:18 AM MST

To: <grass-user@lists.osgeo.org>

Kevin wrote:

For your information -

For rapid band combinations and pan-sharpening of the latest Landsat-8
satellite imagery, you may take a look at the free and advanced image
fusion software from GeoSage.

The software with 2 simple button clicks:

http://www.geosage.com/highview/features_landsat8.html

If you have the latest QGIS installed, click the 3rd button for GeoTFF →
KMZ conversion.

Hope this helps.

Kevin, thanks for the info.

I have tried this tool in the past and it is very nice. However, it is not open-source(d). That’s a huge blocker in trying to understand what’s being done with the data exactly. It would be awesome to have access to the source code and try to replicate it for grass (credits to original authors are always respected, of course).

If you work with grass under Linux, you may want to try out the replication of the HPFA Image Fusion Technique for grass (a bash shell): <https://github.com/NikosAlexandris/i.fusion.hpf.sh>. I my opinion, it outperforms the rest of the available techniques, in both image sharpness and preservation of the original radiometric properties.

I have a work-in-progress python version of this script which I am trying to finalise these days (and hope it will meet the criteria to be included as a grass-addon at some point).

Nikos

2

On 04.11.2014 18:02, Michael Barton wrote:

Nikos,

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

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

Nikos

3

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&gt;, 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.