SAR Image Opening weird Issue

Microwave Toolbox
#1

When I open any SAR images in NEST the image is reversed (like a mirror):confused: No idea what is this about!

Any comment is appreciated!

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#2

Where is the actual image from?

Isn’t this simply ascending vs. descending?

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#3

No, it is just one SLC image (I have tried multiple images either asc or des, the same issue). However, it is opened correctly in any other software like SNAP.

Because I just downloaded NEST, I was thinking maybe some files were crashed or missed… It doesn’t make sense once the image is opened, the software acts like a mirror! :slight_smile:

But I haven’t received any error while installed! Very simple and quick installation.

#4

“mirror” compared with what? In SNAP images are kept is “sensing order” until terrain correction so the 1st sensed pixel is always the top-left corner of the displayed image, which creates a “mirror” effect between ascending vs. descending images of the same area on the ground.

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#5

In SNAP, SLC image looks as it should be. When I open the same SLC in NEST, it’s like the image was reversed! Either asc or des. As shown in the attached screenshot earlier above.

Thanks

#6

Maybe there was a bug in NEST. But NEST was replaced by SNAP. So even if there is a bug in NEST it won’t be fixed.

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#7

I even installed NEST on my laptop, the same problem. It doesnt have a complicated installation which I wanna say I missed sth…

#8

This is the response from NEST support. I thought that it might be helpful to share:

"In regard to your issue:
The image appears to be vertically inverted because it is the product viewer which is orienting the image; the inversion should not impact the data quality or the information contained within.

This is rather a well-known feature of some viewers e.g. SAR products as provided by ESA follows the geometry of acquisition, such that time are increasing with the ‘direction of reading’. This means that for the ascending passes when one looks at the image the North is at the bottom and for descending passes the west is on the right hand side. Most likely, the same thing happens with Radarsat products.

In order to improve the visual inspection, some s/w will flip (north/south for ascending or east/west for descending passes) whereas others will not, however as mentioned above it is NOT an issue at all with the data".