Modified Model of Polarized Bidirectional Reflectance Distribution Function Used for Light Detection and Ranging (LiDAR)

Round 1

Reviewer 1 Report

A comment that you should include about your model, and maybe reiterated in section 2.2 about the Hyde model, is that this is a model for isotropic materials.

A major component of your contribution here is your geometric attenuation factor.  I would suggest you add a reference to Heitz, J. Comp. Graph. Techniques 3(2), 32-91 (2014), which does a nice job detailing the constraints a geometric attenuation factor should have and how it's tied to the chosen microfacet distribution function.  And then a great addition would be your comment on whether or not your geometric attenuation function meets these constraints.

Along with this but with fewer details, does your BRDF model conserve energy in general?  I.e., for any/all incident angle(s), if you integrate over all 2-pi Sr reflectance space, is the directional hemispheric reflectance (DHR) <1?

Referring to lines 315-6, although you may understand this, a common misconception among more-novice microfacet BRDF users is that when you call the real and imaginary parts of the complex refractive index, n and k, characteristic parameters, you are saying they are the characteristic parameters that make your model work for that material; they're not necessarily the actual complex index, n and k, of the material.  You should make that distinction clear for your reader.

In the conclusion, lines 510-3, you say you introduced Kubelka-Monk theory in the paper, but you never did!

In the body, you refer to the "shortcomings of the Hyde model."  In the abstract (and other parts of the body), you call them the "defects of the Hyde model."  Switching all those terms to either "shortcomings," or better yet "limitations," is a much better choice than "defects."

Lines 100-8 are repeats of the previous lines!

Figure 1 is not introduced in the text.  It should be.

You're missing an "alpha" on line 151.

Referring to the sentences contained on lines 371-3 and 379-80, I believe statements like these should be accompanied by references to back them up.

Then, the sentence between them, lines 373-6, is a repeat of the previous sentence.

Not sure what you're trying to say in the sentence on lines 425-7.  It should be clarified.

Author Response

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Reviewer 2 Report

This paper introduces a theoretical pBRDF model comprising three key components designed to depict the reflection property of polarized light on a surface. To account for specular reflection, the model incorporates a geometric attenuation factor. Surface scattering is addressed by modeling a reflectivity parameter, while the subsurface portion is treated with completely depolarized light. The model's parameters are then determined through optimization using measured data from aluminum and white coating targets. This paper offers a supplementary polarization model and could be considered for publication once the following questions have been addressed:

1. Regarding Figure 11, was the simulation without ks generated by keeping all other optimized fitting parameters constant and changing only ks? To establish the superiority of the model with ks, it is advisable to reoptimize without ks and demonstrate the resulting poor fit.

 

2. Does a larger value of ks imply a greater portion of specular reflection? Can you provide an explanation for why the aluminum plate, despite having a larger roughness sigma than white painted coating, exhibits more specular reflection?

 

Additionally, there is a typo error on line427

Author Response

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Reviewer 3 Report

The authors propose a new six-parameter pBRDF model to solve the defects of the classical Hyde pBRDF. By using measured value, the authors verify the accuracy of the model. The topic is interesting and the results are encouraging.

 

Here are my comments:

 

Please refer to the alphabetical order to sort the keywords by their first letter. [Page 1 Line 29]

 

Please consider strength and reorganization the literature review.

 

Please carefully check all the abbreviations. For example, there is no full name of BBO-FA in the abstract.

 

It is recommended that all abbreviations in the figures can be given their full name in the caption.

 

Please notice that all figures should not appear sooner than it is mentioned in the text.

 

There are two figure 5. One is Page 7 Line 240, the other is Page 10 Line 327.

 

Figure 6 and Figure 7: Please give R^2 and RMSE for each subplot in the figure. Why results of aluminum plate seem to be better than that of white paint coating? Any explanations?

 

Figure 11 and 13: Please give R^2 and RMSE in the figure.

 

Please carefully check that all variables are written in italics. For example, Page 12 Line 391, N should be written in italics.

 

Considering add a discussion section to make comparisons with existing research and highlight your innovation.

The authors should really strengthen the English writing skills.There are serious problems with singular and plural, tense and definite article. For example, Page 13 Line 404 "The measured and simulated Stokes vector values L0, L1 and L2 have been normalized in Fig.7. " I guess the authors want to express "The measured and simulated Stokes vector values L0, L1 and L2 were normalized, and their results are shown in Fig.7. "? It is advisable to find a native English speaker to do a thorough grammar check of the text or English editing service.

Author Response

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Round 2

Reviewer 3 Report

I recommend the authors to carefully check all the typo problems throughout the manuscript before publication. For example, in the reference [27], the page information (32-91) is missing.

Author Response

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