Sparse SAR Imaging and Quantitative Evaluation Based on Nonconvex and TV Regularization

Round 1

Reviewer 1 Report

The authors present a method for computing SAR images using sparse signal processing methods, along with a couple of case studies illustrating their method. Overall, I find the paper to be well written and organized. I do suggest that careful grammatical editing be done prior to publication. Here are some suggestions for how the paper might be improved:

 

Page 1, line 33: I suggest adding a more detailed description of what is meant by "region-based features".

 

Page 3, line 89: I think it is important to give a specific definition of what is meant by "down-sampled data". Is anti-alias filtering done before downsampling? Note that the terms "band limited" and "down-sampled" do not in general mean the same thing, so the authors should be sure to clarify this sentence, and use appropriate terminology.

 

Figures 4-6: I suggest adding length scales, or at least indicating in the figure captions the size of the imaged areas.

 

Figures 5-6: I suggest adding color bars to clarify the dynamic range shown in the SAR images. At a minimum, I suggest stating in the figure captions whether all the images are plotted with the same color map.

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

In this article the authors are proposing a method to combine the nonconvex penalty and the total variation norm penalty in the SAR imaging models.

I kindly suggest to the authors to reformulate the first part of the introduction because there are high similarities with their previous article “An Accurate Sparse SAR Imaging Method for Enhancing Region-Based Features Via Nonconvex and TV Regularization” published in IEEE.

In the Discussion section, the downsampling condition could be applied also for changes in the elevation angle?

In the Conclusion section can you provide some future work elements?

Good Luck!

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

Please, see the attached word file.

Comments for author File: Comments.pdf

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Good Luck!

Reviewer 3 Report

The paper presents sparse SAR imaging task by using the variable splitting scheme and the alternating direction method of multipliers (ADMM). This idea is in my opinion slightly interesting.
It also should be noted that the paper has been already considerably improved through a deep revision carried out during the submission to the MDPI remote sensing journal.
The work is clear from the mathematical point of view, well written and organized, and I judge it to be free from basic errors and faulty expressions.
For all the above, publication of this manuscript on MDPI remote sensing is recommended after modifying minor grammatical errors.