Round 1

Reviewer 1 Report

The article clearly presents the purpose of the research. The research topic is very contemporary. The problem of measuring cramped, narrow and dark spaces arises in many situations (tunnels, tunnels, mines, cultural heritage, ) and is linked to problems of safety, accessibility, and survey time, ...

Figure 3. Front view? Or top? These two images are not so clear. I suggest replacing them, and also put the scale bar, in order to appreciate the real dimension of the place.

What is the maximum measured tunnel length?

About the camera: How was the camera calibrated? Is the camera carried by hand? Or is it mounted on some device?  Have you tried photogrammetric systems? (HANDHELD FISHEYE MULTICAMERA SYSTEM: SURVEYING MEANDERING ARCHITECTONIC SPACES IN OPEN-LOOP MODE – ACCURACY ASSESSMENT L. Perfetti, F. Fassi, ISPRS  2022).

There are several examples of research presenting mixed technology solutions (laser and imaging). Backpack or hand-held solutions are interesting. About instruments, the bibliography can be expanded with more contemporary references.

Have you observed any drift effects? (along the entire path) comparing point clouds and topographic points.

Figure 9 is also unclear. Better to put image captures taken from the same point of view.

In Figure 12. is the section the same? they look different.

Author Response

Response to reviewer 1 comments

Dear Reviewer,

We deeply appreciate the effort and time you’ve spent in reviewing our manuscript “RGB-D Camera for 3D Laser Point Cloud Hole Repair in Mine Access Shaft Roadway” (ID: applsci-1864643). We studied the comments carefully and have made revisions which we hope meet with your approval. The outline of the revisions is listed as follows:

• We have added some quantitative results after the experiment to the summary section. (Please check the abstract section)
• We have added a discussion of the application of laser technology in different industries in the introduction section. (Please check the Introduction section)
• We have added some more detailed descriptions of the images acquired by the RGB-D camera. (Please see Section II)
• We have added a more detailed description of the study area with respect to tunnel information. (Please see Section III)
• We have added RGB-D cameras to be described in more detail in the camera calibration section. (Please check Section III)
• We have checked the experimental results of the whole manuscript carefully.
• We have checked and revised the image format of the entire manuscript carefully.
• We have revised the entire manuscript, revising some issues with terminology meticulously.

Comment #1

Figure 3. Front view? Or top? These two images are not so clear. I suggest replacing them, and also put the scale bar, in order to appreciate the real dimension of the place.

Response:

Thank you for helpful comment. We have reworked Figure 3 and added clarity to it. We have given a full view of the entire mine, an orthomosaic with the top of the mine, and added a scale to the orthomosaic. Please refer to lines 122-123 on page 4, Figure 3.

Comment #2

What is the maximum measured tunnel length?

Response:

Thanks for your this comment. We have added some basic data on mine tunnels to the description of the study area. The total length of the mine tunnel is 384m. We performed data acquisition by ground-based 3D laser scanners. We made a total of 39 acquisitions. Please refer to line 129-135 on page 4.

Comment #3

About the camera: How was the camera calibrated? Is the camera carried by hand? Or is it mounted on some device?  Have you tried photogrammetric systems? (HANDHELD FISHEYE MULTICAMERA SYSTEM: SURVEYING MEANDERING ARCHITECTONIC SPACES IN OPEN-LOOP MODE – ACCURACY ASSESSMENT L. Perfetti, F. Fassi, ISPRS  2022).

Response:

Thanks for your helpful comment. We have added a description of camera calibration in the section on RGB-D camera data acquisition. It can be calibrated without the traditional chevron pattern calibration; it has automatic calibration function. We perform data acquisition through handheld cameras, and the collected data can be transferred directly to the computer. For the photogrammetry system, we have not yet conducted research, we think this is a very good idea, the next will be studied from this aspect, thank you very much for your comments. Please refer to line 183-191 on page 6.

Comment #4

There are several examples of research presenting mixed technology solutions (laser and imaging). Backpack or hand-held solutions are interesting. About instruments, the bibliography can be expanded with more contemporary references.

Response:

Thank you for this comment. We have added some descriptions of the different industrial applications of laser technology in the introduction section and expanded the references. Please refer to lines 40-82 on page 1-2.

Comment #5

Have you observed any drift effects? (along the entire path) comparing point clouds and topographic points.

Response:

Thank you for this comment. We found a small number of error points in the data during the data processing, and most of these points were isolated. For these error points, we removed these points by filtering the data.

Comment #6

Figure 9 is also unclear. Better to put image captures taken from the same point of view.

Response: `

Thank you for this comment. We modified Figure 9 to increase its clarity. Please refer to lines 236 on page 7, Figure 9.

Comment #7

In Figure 12. is the section the same? they look different.

Response: `

Thank you for this comment. Figure a in Figure 12 is captured by a ground-based 3D laser scanner, which has a low point cloud density. Figure b is captured by the RGB-D camera, which has a high point cloud density. We have measured the same feature points for both point cloud data and compared them to each other, and they are in the same location.

Author Response File: Author Response.docx

Reviewer 2 Report

The paper “applsci-1864643-v1” discusses interesting note but needs significant improvements. Please follow the comments carefully.

1.      What the author is trying to show by presenting fig1. Depth cameras with different imaging principles. (a) Structured light camera ;(b) Time of Flight camera; (c) Binocular vision camera

2.      Add some quantitative results to the abstract.

3.      What is the main contribution of the paper? You need to highlight this.

4.      Add more detail to the conclusion.

5.      Provide a thorough discussion of reported results in Figure 2. The color section needs more explanations.

6.      Check all figures. For example figure 17-2 has a big gap on right hand side.  

7.      Laser has different usage in various industry  and are such as additive manufacturing. Add a short paragraph to your introduction and say this and add these four papers as an example.

·        The effect of absorption ratio on meltpool features in laser-based powder bed fusion of IN718

·        Lightweight design of an AlSi10Mg aviation control stick additively manufactured by laser powder bed fusion

·        Fatigue life optimization for 17-4Ph steel produced by selective laser melting

 

·        Offline laser power modulation in LPBF additive manufacturing including kinematic and technological constraints

Author Response

Response to reviewer 2 comments

Dear Reviewer,

We deeply appreciate the effort and time you’ve spent in reviewing our manuscript “RGB-D Camera for 3D Laser Point Cloud Hole Repair in Mine Access Shaft Roadway” (ID: applsci-1864643). We studied the comments carefully and have made revisions which we hope meet with your approval. The outline of the revisions is listed as follows:

• We have added some quantitative results after the experiment to the summary section. (Please check the abstract section)
• We have added a discussion of the application of laser technology in different industries in the introduction section. (Please check the Introduction section)
• We have added some more detailed descriptions of the images acquired by the RGB-D camera. (Please see Section II)
• We have added a more detailed description of the study area with respect to tunnel information. (Please see Section III)
• We have added RGB-D cameras to be described in more detail in the camera calibration section. (Please check Section III)
• We have checked the experimental results of the whole manuscript carefully.
• We have checked and revised the image format of the entire manuscript carefully.
• We have revised the entire manuscript, revising some issues with terminology meticulously.

Comment #1

What the author is trying to show by presenting fig1. Depth cameras with different imaging principles. (a) Structured light camera ;(b) Time of Flight camera; (c) Binocular vision camera.

Response:

Thank you for this comment. We wanted to show the different depth camera in the form of pictures.

Comment #2

Add some quantitative results to the abstract.

Response:

Thanks for your this comment. We expanded the abstract with the results of the study. Please refer to line 14-29 on page 1.

Comment #3

What is the main contribution of the paper? You need to highlight this.

Response:

Thanks for your this comment. We add the significance of our research and our contribution to the development of the industry at the end of the introduction. Please refer to line 76-82 on page 2.

Comment #4

Add more detail to the conclusion.

Response:

Thank you for this comment. We add more description of the study details to the conclusions. Please refer to lines 384-403 on page 13-15.

Comment #5

Provide a thorough discussion of reported results in Figure 2. The color section needs more explanations.

Response:

Thank you for this comment. We have described in more detail the color images and depth images acquired by the RGB-D camera. Please refer to lines 98-112 on page 3.

Comment #6

Check all figures. For example figure 17-2 has a big gap on right hand side.

Response: `

Thank you for this comment. We checked all the figures in the article and corrected any errors.

Comment #7

Laser has different usage in various industry  and are such as additive manufacturing. Add a short paragraph to your introduction and say this and add these four papers as an example. The effect of absorption ratio on meltpool features in laser-based powder bed fusion of IN718; Lightweight design of an AlSi10Mg aviation control stick additively manufactured by laser powder bed fusion; Fatigue life optimization for 17-4Ph steel produced by selective laser melting; Offline laser power modulation in LPBF additive manufacturing including kinematic and technological constraints

Response: `

Thank you for this comment. We have added more descriptions of laser technology in the introduction section and applied these 4 articles. Please refer to lines 33-32 on page 1-2.

Author Response File: Author Response.docx

Reviewer 3 Report

Dear Editor/ Authors,

Usage of terrestrial laser scanning (TLS) technique is getting wider in recent years. Too much studies have been going on to improve the efficiency of technique especially for underground applications. The authors used RGB-D data with TLS data to improve the accuracy of point cloud by completing the missing parts. Also they determined the best algorithm for merging the two data acquired from two techniques.

I think the study was done systemically and results are consistent.

 This manuscript potentially has a positive contribution for other researchers.

As the result of the review, some issues that should be considered;

The text should be edited by a Professional editing service. Although the text is grammatically fine the terms used in text should be matched with the literature usage.

Please extent the introduction part. Previous studies should be given in introduction part. Also you should indicate the differences of your study from previous studies.

Please add some information about study area such as dimensions of tunnel, length of measurement area etc.. Also add the total scan number, RMS for registration of scans and total number of points after registration for TLS and RGB-D measurements (Should be given with table)

Figure 11-2. Is that point cloud data or solid model created from point cloud data?

Please also give the RMS results of each method in related parts. Not only in Table 1

In Table 1 “Number of point clouds participating in RMSE calculation” are these the number of point clouds or points? I think the numbers are belong to points. Point cloud and point are different terms.

Author Response

Response to reviewer 3 comments

Dear Reviewer,

We deeply appreciate the effort and time you’ve spent in reviewing our manuscript “RGB-D Camera for 3D Laser Point Cloud Hole Repair in Mine Access Shaft Roadway” (ID: applsci-1864643). We studied the comments carefully and have made revisions which we hope meet with your approval. The outline of the revisions is listed as follows:

• We have added some quantitative results after the experiment to the summary section. (Please check the abstract section)
• We have added a discussion of the application of laser technology in different industries in the introduction section. (Please check the Introduction section)
• We have added some more detailed descriptions of the images acquired by the RGB-D camera. (Please see Section II)
• We have added a more detailed description of the study area with respect to tunnel information. (Please see Section III)
• We have added RGB-D cameras to be described in more detail in the camera calibration section. (Please check Section III)
• We have checked the experimental results of the whole manuscript carefully.
• We have checked and revised the image format of the entire manuscript carefully.
• We have revised the entire manuscript, revising some issues with terminology meticulously.

Comment #1

The text should be edited by a Professional editing service. Although the text is grammatically fine the terms used in text should be matched with the literature usage.

Response:

Thank you for this comment. We carefully revised the entire manuscript and modified some of the terminology. At the same time, we asked some colleagues who are fluent in English to help us check the language.

Comment #2

Please extent the introduction part. Previous studies should be given in introduction part. Also you should indicate the differences of your study from previous studies.

Response:

Thanks for your this comment. We have added to the introduction a more detailed description of laser technology and industry use, and the differences and implications of our research from other studies. Please refer to line 33-82 on page 1-2.

Comment #3

Please add some information about study area such as dimensions of tunnel, length of measurement area etc.. Also add the total scan number, RMS for registration of scans and total number of points after registration for TLS and RGB-D measurements (Should be given with table)

Response:

Thanks for your this comment. We have added more information to the description of the study area section and data collection. Please refer to line 125-135 on page 4; line 164-171 on page 5; line 378 on page 13, table 1.

Comment #4

Figure 11-2. Is that point cloud data or solid model created from point cloud data?

Response:

Thank you for this comment. The data in Figure 11-2 is point cloud data, which is enlarged (voxelization) during processing to facilitate viewing of the alignment results, and the final output is still point cloud data.

Comment #5

Please also give the RMS results of each method in related parts. Not only in Table 1

Response:

Thank you for this comment. We added the value of RMSE for each experimental section. Please refer to lines 316 on page 10; lines 333 on page 11; lines 347 on page 12; lines 361 on page 12.

Comment #6

In Table 1 “Number of point clouds participating in RMSE calculation” are these the number of point clouds or points? I think the numbers are belong to points. Point cloud and point are different terms.

Response: `

Thank you for this comment. We corrected the terminological errors in Table 1 and checked other terms in the manuscript. Please refer to lines 378 on page 13.

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

The paper is ready to publish.

Author Response

Response to reviewer 2 comments

Dear Reviewer,

We deeply appreciate the effort and time you’ve spent in reviewing our manuscript “RGB-D Camera for 3D Laser Point Cloud Hole Repair in Mine Access Shaft Roadway” (ID: applsci-1864643). We studied the comments carefully and have made revisions which we hope meet with your approval. The outline of the revisions is listed as follows:

• We have modified the images that were not clear.
• We carefully revised the entire manuscript, fixing grammatical and syntactic errors. At the same time, we asked some colleagues who are proficient in English to help us check the language.

Author Response File: Author Response.docx