Methods and Algorithms of Subsurface Holographic Sounding

Round 1

Reviewer 1 Report

I think this is a valuable experiment, and its observation and analysis might contribute to significant advancement in the field of microwave holography. Following are my recommendations to improve the manuscript.

1. Figure qualities are not good; the labels, X and Y axis were not clear in many of the figures (for example, in Figs. 6,7,12,21,22,24, labels and ticks were barely seen). As a result, it was hard to assess.
2. ‘Methods of subsurface radar holography’ (sec 3) should precede ‘the Experimental realization’ section (sec2). 
3. Lines 354-356: The implication of the results was not well supported and discussed. “The results of coherent multi-view hologram summation allow one to estimate the object shape and location. This complex of laboratory experiments proved the possibility of subsurface object location and suggested the methodology of oblique subsurface sounding in field conditions.” - Please, explain how?
4. In the abstracts the authors mentioned that “Laboratory and field tests confirmed the predicted device parameters.”- What are the parameters? Please, clarify. 
5. The conclusion is also too short, lacking sufficient contexts.
6. I recommend discussing the agreement between the simulation, laboratory, and field tests.
7. Please, remove the text on line 148 “ Этот абзац относится к схеме рисунка 9. ”
8. Did you mean the ‘inverse Green theorem’ in lines 174 and 184?

Author Response

Thank you for your expert suggestions.

Kind regards,

Alexei Popov

Author Response File: Author Response.pdf

Reviewer 2 Report

Please see the attachment

Comments for author File: Comments.pdf

Author Response

Thank you for your expert suggestions.

Kind regards,

Alexei Popov

Author Response File: Author Response.pdf

Reviewer 3 Report

The paper can be of interest for the microwave engineering community dedicated to microwave imaging techniques. Some items should be improved to a better understanding for a reader expert in this techniques.

Line 43: Kirchoff inversion procedure: Maybe it is something known but this Kirchoff procedure is not described in the paper. Please, add a brief description or give a convenient reference.

Line 75. Fig 2 is not complete. The bottom image seems to be distorted or bad added to the text. Please review it. 

Line 98: Dry sand. What are the dielectric characteristics of dry sand? Have you tested it alone at the interest frequency? What are its dielectric constant and its loss tangent?

Lines 121 to 130: Are the tests done in far field or in near field condition? How is the uniform irradiation achieved?

Lines 132 and 135: Reinforcement bar: What type of material has this bar? Is it metallic or dielectric? Please add details of material and dimensions of this reinforcement bar.

Line 148: There is a text written with russian words. Please translate or delete.

Line 154: It should be "object" instead of "obgect".

Lines 164 and 165: What are the dimensions and the location of the flat metallic object? What type of material?

Lines 171 and 172: There is not a scheme of the receiver (block diagram), then it is difficult to understand how the ortogonal components of the received signal are obtained. Please, add a description and at least a block diagram of the receiver.

Line 175. Equation (1). Variables inside the integral are not described. To explain what is each variable and the meaning of this equation.

Line 178: Fig. 9. It is a figure difficult to understand. What is the figure on the right? What are the arrows and what is S ?

Lines 187 and 188: What are the variables in this expression?

Lines 191 to 196: There are many variables not described in the text. In general the contents from line 187 to line 207 is very confused. For instance: How are defined the illumination angles? How is defined the antenna aperture?

Line 217: How many irradiance angles have been used?

Line 227: Why do you use a layered inhomogeneous dielectric medium? Is not the dry sand an homogeneous medium?

Line 255: What type of material has a relative dielectric permittivity equal to 9?

Lines 314 to 320: Variables that are in Figure 17 does not have the same name as is in the text. For instance: probing distance L does not appears in teh Figure 17. What is the "O" in the figure? What are the stars symbols? What are the metallic rod dimensions and what is the material?

Lines 352 and 353: What is the disk material?

Author Response

Thank you for your expert suggestions.

Kind regards,

Alexei Popov

Author Response File: Author Response.pdf

Round 2

Reviewer 3 Report

In my opinion the manuscript has been sufficiently improved to warrant publication in Remote Sensing.