When I try to coregister two ALOS 2 SLC (level1.1) images I get the error " The specified region, if not null, must intersect with the image`s bound"
PS I follow these steps for coregistration, and I check “estimate initial coarse offset” in coarse correlation, while the rest of the parameters are kept their default value -
Please take a look at this thread,
Source of the thread
Also might be missing some data is a couse of error,
Take a look at this post
@falahfakhri Sorry I had completely misunderstood what you said and so Im editing my post.
Your suggestion was right, the there are some metadata missing. The post you referred to suggests that the metadata was “mis-read” due to some previous operations done on the image using another software.
But in my case I just “unzip” the folder and open the ALOS 2 images by using the “import” option and then selecting “SAR Sensors” and finally “ALOS 2 CEOS”
Can you suggest what I can do now?
I had this once, try without coarse offset estimation (uncheck the corresponding box).
I tried that, in that case my interferogram does not come out looking good…
Any other suggestions are welcome, and actually would be really helpful…
but that means that the coarse registration caused the error you reported above.
Try again (without coarse offset estimation), but increase the number of GCPs (5000 if you have the processing power) and lower the RMS threshold accuracy to 0.001 in the “Warp” tab.
This should increase the quality of the coregistration (you can check it before computing the interferogram as described here)
I see that increasing GCPs and Lowering RMS threshhold (like you suggested) improves the results, a little bit, but they are still not as good.
But do you think that if coarse coregistration was possible, it would further improve my results? And also I may have found the reason why the coarse coregistration was failing (thanks to @falahfakhri ) , please see the pictures of the metadata, where the absolute orbits are found but relative orbit or incidence angle (near and far) are not found. Although this is the case of the metadata, but in the Tie Points Grid, there is a band for incidence angle…
Any idea how I may solve that, because I searched the forum and the only time people had a similar problem with Alos was when they extracted processed data (from softwares other than snap) in the same folder containing the original image files. But I have maintained seperate folders and coregistration is the only and first operation I have run…