Rapid Calibration of the Projector in Structured Light Systems Based on Brox Optical Flow Estimation

Round 1

Reviewer 1 Report

The authors have addressed my comments. Now, It can be accepted.

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

The manuscript requires the major revising. English language of the paper has to be improved. The authors are to check their terminology. The terms "structured light' refers to various kinds of special light beams like optical vortices, Airy beams, Bessel beams etc. The authors mistakenly used it when speaking about the optical patterns, applied to 3D-laser scanning.

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

This paper reports a rapid calibration technique for locating the projector in the structured light measurement system where using Brox optical flow, the calibration of the 3D coordinates of the projector only requires two images captured before and after the motion of the calibration plate. I have some questions.

1. In the simulation experiment I miss some details. How the optimal parameter values were considered? Please be clear and improve.
2. Introduction: I miss some literature that it can be useful for sensing like: Nat Commun 7, 10870 (2016); Optical and Quantum Electronics 48 (3), 1-8, 2016; Electronics 8 (2), 173, 2019. How the proposed system from the authors can improve or add value for this kind of application? Please be clear and add some sentences.
3. What are the main concerns in tems of resolution of the system?
4. What are the problems to be solved to get identical performance analysing  similar or different movements?

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 3 Report

The paper is ready for publication

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

The manuscript presents a rapid calibration technique for locating the projector in the structured light measurement system using Brox optical flow estimation.

1.The group of equations after the Equation (4) makes the manuscript difficult to read, it is highly recommended adding the definitions before or to specify a related reference.

2. In Fig. 1 the axis labels and/or variables are hard to distinguish. In general, labels in the images throughout the manuscript are not distinguishable.
3. The images in Fig. 4 and 6 do not specify the scales on the xy axis, nor do they show a scale palette; it is necessary to provide complete information for simulations or experimental results.
4. The photograph of the experimental setup is too bad. We recommend you to be more serious when making your reports: add in your photograph the trace of each one of the distances and parameters; label each one of the components, specify the variables, etc, in the same way in which the diagram of the experiment was described.        a. How do you adjust the position of the projector?                              b. In the picture, the camera mount is not distinguishable.                    c. The labels with that white box do not help in the description of your experimental arrangement.
5. The experimental results are not in agreement or validate what the authors claim in their abstract. In their results they only compare their method with other techniques, but they do not show a complete statistical analysis that could validate the proposed method.
6. The numbering in the title of the conclusions is incorrect.
7. The manuscript has a large number of formatting errors.
8. These techniques are well-known; however, throughout the text you can find information that lacks the addition of related references. This can be noticed immediately in the very limited extension of the references section, so the introduction is incomplete and shows a poor review of the state of the art.

 

The manuscript does not report on research results, but actually it describes a basic experiment that can be performed in a specialized optics course.

 Thus, I think this manuscript is not acceptable for publication in PJ. Perhaps, after a major revision, it could be acceptable in a journal devoted to physics teaching, as, for example, Am. J. Phys.

Reviewer 2 Report

This manuscript proposes a calibration of the projector which provides both a fast calibration and some discussions of robustness. The projector calibration only requires two images of the calibration plate is interesting, even if it is simple enough. The paper is however not complete; given the increased interest in 3D measurement, for example, it could be considered for publication in the journal, with the major corrections pointed out below.

Q1. The serial number of the conclusion chapter is wrong.

Q2. Besides camera calibration methods like those the authors are approaching in this work, the authors are suggested to point out alternative optical systems in the Section I. For example: Zoom lens (reference A, Calibration procedure of camera with multifocus zoom lens for three-dimensional scanning system), telecentric lens (reference B), self-calibration (reference C)…

Q3. The progress of the proposed method cannot be directly found from the experimental results and Figure 15. It should have comparisons of absolute accuracy, surface roughness and the relative standard deviation, measuring range, and the number of calibration images.