[seppi-santiago]

Hello Daniele,

I am having a problem with Sparse Point Selection (both in the APS Processing and/or the Sparse Points Selection section which is in blue) . The process of selection seems to get stucked at the Mask Loading step. In previous opportunities I made tests with smaller datasets, of only 3 images, but now I’am working with a dataset of 9 images. I don’t know whether the number of images in the dataset should affect the Load of the Mask or not. If that is the case maybe I should just wait for it to finish.
Just in case I enclose the Mask file (maschera.mat), there is no log file written for the session yet.

Thanks,
Santiago

[seppi-santiago]

Daniele,

I’m sorry, the mask zipped file exceeds the maximum allowed limit

[periz]

the mask file is independent from the number of images
it would be nice to know how big is maschera.mat, and which is the size of your dataset (samples and lines).
by the way, which option did you use for mask generation?
are you working with windows? what’s the size of the RAM?

[seppi-santiago]

I am working with Windows. My dataset is not very big (ca. 3600 samples x 3100 lines). For the mask generations, I used the local maxima option (second one). You can download the Maschera.mat from here
https://www.dropbox.com/s/0arzdxjgwpizkxy/Maschera.mat?dl=0

[periz]

there is no evident reason for your problem
the file is 2.2MB, less than 1.5e6 points
loading the file in matlab takes a few seconds
I am wondering whether you could have problems affecting matlab and/or windows installation.
or maybe some problems in reading/writing operations: is the file on a local or external disk?
which kind of disk are you using? is windows having enough free space in the installation disk?
other question: which parameter are you trying to read?
The sw firstly loads the mask, then it uses the sparse points to read your parameter (if it’s a full matrix, this is the operation that can take a bit of time more. in particular if you are using a slow external disk).
if you press CTRL+C at the matlab prompt when it gets stuck, you could show me the error message and we may get more hints

[seppi-santiago]

Hello,

The file is on a net disk, so I think this should not cause major problems. Windows has more than 500 available gb, and the usage of RAM memory is about 50% when running this command. The parameter from which I’m trying to select the points is the Amplitude Stability Index (Amp. Stab. Index 1-Sigma/Mu). I enclose a screen shot, since in my compiled windows version CTRLC + C causes the termination of the program.

Thanks,
Santiago

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[periz]

On the contrary, I believe the net disk is the major problem.
Can you check the network usage?
Or can you simply try to copy the dataset locally? Note that you do not need the SLC folder. So, I believe the rest of the folders should be quite small.

[periz]

On the contrary, I believe the net disk is the major problem.
Can you check the network usage?
Or can you simply try to copy the dataset locally? Note that you do not need the SLC folder. So, I believe the rest of the folders should be quite small.

[seppi-santiago]

Indeed, you were right. Now that I’m working locally the mask loading works perfectly. Thanks!

[seppi-santiago]

Hello d,

Normally I’ve created the mask with the ‘Local Maxima from Reflexivity’ option. Could you explain how the other options work for te Mask creation?

-local maxima extraction with range lobes suppression
-local maxima extraction with range and azimuth lobes suppression
-regular grid, spaced dS by dL

thanks

[periz]

-local maxima extraction with range lobes suppression
-local maxima extraction with range and azimuth lobes suppression

these two options are useful for suppressing ghost targets generated by side lobes of the impulse response of the system (cardinal sine). in fact, side lobes could already be suppressed by filters used in the focusing process. so, it’s an advanced option useful only in particular cases.

-regular grid, spaced dS by dL

if you are working with full resolution data, don’t use this option. this option could be useful in case you work with filtered/multilooked data and you want to analyze a regularly spaced grid

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