[seweryn]

Hi SARPROZ team,

I have the following questions regarding the change detections modules:

-How we can use the results of different options (for example for the CCD 2 and MTC 2 options) in the Multi-channel change detection in the software to detect change? it is making a RGB file with tiff format, it sounds it needs thresholding on the R, G and B value to finally detect any change, can we do this in the software? or do you have any other suggestions? .

-it sounds there isn’t any help for the change detection module, is it just a simple normalize difference? like (B-A)/B+A for each pixel between image A and image B?

Many thanks,

[periz]

Hi,
regarding your first question, the outputs of the multi-channel change detection module (shortly described here https://sarproz.com/manual/rgb_module.html) are common outputs that the radar community knows how to interpret. Usually, those outputs are evaluated visually. If you want to set thresholds, you have to build them yourself, e.g. via the “scatter plots” module: https://sarproz.com/manual/xplot.html. If you do not know how to interpret the outputs, I suggest you to take a radar course.
About your second question, yes, it’s just a normalized difference, ad-hoc filtered in space. There are some brief basic tutorials about it on this site (tutorials section), and some brief papers (scientific publications section). Again, probably the most effective way for you to take out the best from these tools is to attend the Sarproz course (a session is starting next week, not sure if seats still available).
best

[seweryn]

thanks for your reply.

The results of multi-temporal change detection is a tif file that cannot be loaded in the scatter plot module. we need to have a .mat file like the results of change detection module. Could you please let me know how to load it in the scatter plot module?

Thanks

[periz]

the tif file is a 3 channels product. the inputs of the 3 channels (which you can pick up as you like) are all products that can be loaded in the scatter plot module. not as a color clearly (which has to be a scalar), but you indicated you wanted to threshold the MTCD product. so, in the boolean section of the scatter plot module you can implement a selection like e.g. (R > r0 & G < g0) | B > b0 or whatever else you like by playing with <> &| and so on. in this way you select the points you want. then you can either export this selection and use it somewhere else or you can plot your selection in the same module.
again, a sarproz course would be strongly suggested
best

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