TomoSim: A Tomographic Simulator for Differential Optical Absorption Spectroscopy
Round 1
Reviewer 1 Report
- Equation (6) contains terms that are not correctly explained
- Reference 7 does not refer to Levenberg-Marquardt equations – see the contents.
- In the paragraph:
”In all conventional simulation, individual treatment field geometries are determined at the time of simulation. Target and other data are often drawn or annotated on each film or digit”
the presented tomography simulation method does not comply with the requirements for a tomographic investigation that takes over the data in a short time
4. Equation (9) is misspelled. (The correct expression is in reference 17 equation 9)
5. The influence of the grid was not discussed at all. which is the minimum size of th
Author Response
I would start this reply by thanking the reviewer for his or her time and for the comments that he or she made to my work.
To the comments themselves:
1. Equation (6) contains terms that are not correctly explained.
In fact, this equation's terms could be better explained and there are even some definitions lacking. Thank you for pointing this out.
2. Reference 7 does not refer to Levenberg-Marquardt equations – see the contents.
I am sorry but I do not understand the comment. Reference 7 points to William H Press's Numerical Recipes. This book details the Levenberg-Marquardt algorithm in section 15.5.2.
3. In the paragraph:
”In all conventional simulation, individual treatment field geometries are determined at the time of simulation. Target and other data are often drawn or annotated on each film or digit”
the presented tomography simulation method does not comply with the requirements for a tomographic investigation that takes over the data in a short time.
I am sorry but I could not find the cited paragraph in our text. Could the reviewer please clarify the question?
4. Equation (9) is misspelled. (The correct expression is in reference 17 equation 9)
I am sorry but I could not find where the mispelling might be. The reviewer points to reference 17, which is the MLEM reconstruction technique paper by Shepp and Vardi. This paper does not address our paper's equation 9, nor does it have an equation 9. Moreover, according to equation 13 of reference 16 (the paper by Andresen and Kak that establishes the SART technique) the equation seems to be well written. Maybe the reviewer could point to where exactly he or she thinks the equation is mispelled so that we can correct it accordingly.
5. The influence of the grid was not discussed at all. which is the minimum size of th
This comment is unfinished, so I will presume the question was directed towards the influence of the grid in the reconstruction process. The grid size is of course very important in terms of reconstruction, since it determines the resolution with which the final image is created. The reason why this parameter was not further discussed in this paper is because in simulation we can make the grid as small as we want. This would of course impact the graphical presentation of the reconstructed images and the computation time. In real life, this would have to be quantified with respect to the instruments that the drone would carry with it, becoming much more complex.
The grid we have chosen to perform reconstruction would translate to a roughly 5m pixel grid in real life, considering a 300 pixel image with a 1km diameter drone trajectory, which is a reasonably ambitious size and is in line with the type of spatial resolution presented in other papers with smaller projection numbers than ours.
Reviewer 2 Report
General
The article presents an interesting approach to the selection of the optimal method of processing tomographic data obtained using the simulation software package. The research was performed in a convincing way. The authors formulated constructive conclusions regarding the selection of the best reconstruction algorithm. They also proposed valuable further directions of research to further develop their solution.
Suggestions for Authors
In order to improve the reception of your work, please consider some remarks I have noticed while reading the text.
1. Although the "DOAS" acronym is common among some audiences, readers of the journal to which the article was submitted are a broad group and may not be familiar with it. Please consider expanding this acronym in the abstract and changing the title.
2. Lines 22-23: Unfinished sentence.
3. Line 47: The order of sections is questionable. Sections 2 and 3 should be placed after Section 4.
4. Line 61: What does "optical path" mean? Do you mean its length?
5. Line 128: Please explain the meaning of "function in R".
6. Line 241: The mentioned paper should be referenced here.
7. Line 250: "previous two sections" - there is only one section before.
8. Line 251: It is incomprehensible why Section 4 is not placed earlier, as it is referenced frequently throughout Section 2.
9. Line 267: "subsection" -> "section"
10. Lines 268-270: Does Figure 3 really contains an example of the number of projections used? Please verify.
11. Line 273: The geometric error is defined in Section 4.5. The definition should be introduced before discussion.
12. Line 340: The acronym "ROI" should be explained by first occurrence.
13. Line 350: What is the time interval between the 1st and 2nd moments? Can there be a change in the state of the phenomenon under study or in the weather conditions during this time interval, which affects the results obtained? How to deal with such a problem?
14. Line 354: Examples of points A, B in Figure 7 would be helpful.
15. Figure 7: The question is placed in the attached PDF file and also available here:
https://www.dropbox.com/s/8vfjd8ckfiozcdh/fig7.jpg?dl=0
16. Lines 376-377: Please consider providing information about the noise parameters.
17. Line 410: "On the spectroscopic" - new line.
18. Line 415: "Finally" - new line.
19. Line 424: Recreate the reconstruction? Maybe rather create the reconstruction?
20. Language.
Although English is not my native language, I see a few imperfections (listed below) that may indicate the need to consult a native speaker if it was not done before.
* Lines 29-32: Please consider another beginning: "This strategy, which is one of the core components of this tool, is predicated...". Moreover, please avoid, if possible, such long sentences.
* Line 59: This sentence should not rather begin with "In which".
* Line 68: "of which" -> "one".
* Lines 78-79: This sentence sounds disorderly.
* Line 80: "Besides these" -> "Besides"
* Line 106: This sentence should not rather begin with "Where".
* Lines 132-133: "…and the data it contains". Contains what? This is unclear.
* Lines 270-271: "since there are already in the literature many examples of studies". This part sounds disorderly.
* Line 322: "but are also" -> "but also"
* Lines 423-424: "platform with which to" -> "platform to"
* Lines 468-469: "is taking a spectrum in of its stops". This part sounds unclear.
Comments for author File: 
Comments.pdf
Author Response
Before addressing the comments themselves, I would like to extend our
gratitude to the reviewer for accepting to review our work and for the
time doing it took.
Here is our reply, point by point:
1. True. Will correct as requested;
2. Will rewrite accordingly;
3. The order of the sections was set by the MDPI template, but I agree
with the reviewer and will try to address this;
4. The optical path is the path that a ray of light describes in an
optical system. I will include this definition in the text;
5. A function in R is a function that has the real numbers as its
domain. I will include this definition in the text;
6. Will correct;
7. Will correct;
8. This is the same problem as comment #3 and will be addressed at the
same time;
9. Will correct;
10. The sentence should be better written. What we meant was that Figure
3 proves that the number of projections taken is sufficient to produce
an image;
11. Same problem as comment #3 and comment #8. Will be addressed in the
same manner;
12. True. Will address this as requested;
13. Yes there could be a change and this is a very valid point that can
be addressed and mitigated by adding a second drone. This would allow
both measurement moments to occur at the same time. I will include this
in the text;
14. I will try to include this if it does not result in a too
graphically dense image;
15. This is true. I will try to correct this, but I am not sure how an
angular interval can be ensured in a graphical editing software;
16. Will include this in the text;
17. Will rewrite;
18. Will rewrite;
19. Will rewrite;
20. Will rewrite;
In addition to this, we will also take the reviewers language
suggestions into consideration in the final text.
Round 2
Reviewer 2 Report
Thank you for considering my suggestions.
