A Survey of Low-Cost 3D Laser Scanning Technology

Round 1

Reviewer 1 Report

The presented work discussing a thrust area of interest, and figure out the main issues to guide researchers during their research.

I have few comments related to formatting:

Line 196: position is not suitable.

Line 924: prices should be shown in USD as a reference known currency.

 

 

Author Response

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Reviewer 2 Report

In this Review, the Authors survey and classify different prototypes of moving 2D lidar systems. The main arguments for the need of this review are the following: 1) by using a moving 2D lidar, 3D maps of the environment can be built in a much more economical way than using a 3D lidar; 2) in the next few years, the price of 3D lidar is unlikely to drop; therefore, as long as there is a significant price difference between 2D and 3D lidars, it is worth improving moving 2D lidar systems. The Authors classified a moving 2D lidar into 6 categories and, for each category, they described a series of problems that need to be solved to make the different prototypes perform better. I find the paper relevant, well written, and illustrative, and I recommend its publication.

Please just correct the following. The word “attitude” is mistakenly written instead of the word “altitude”. This is the case in at least 17 instances throughout the paper. Please correct and double check for other mistakes or typos.

Author Response

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Reviewer 3 Report

In this paper the authors compare two laser scanner technologies to reconstruct  3D Maps of the environment: a low cost 3D laser scanning with a moving 2D lidar considering the lower construction cost.

The study presents a rich review of the protitypes with a detailed and well organized structure.

 

Anyway to improve the paper deepening the comparison I would suggest to highlight the peculiarities of the technologies in their specific field of application, describing the  strengths and weaknesses to optimize the survey project. With this aim the authors could improve the paper adding specific studies in civil engineering. For example speaking about civil infrastructure areas, or application in costal areas:

• Applications in civil infrastructure areas:

Barbarella, M., De Blasiis, M.R., Fiani, M. Terrestrial laser scanner for the analysis of airport pavement geometry. International Journal of Pavement Engineering 2018 20:4, 466-480, DOI: 10.1080/10298436.2017.1309194

Barbarella M., D’Amico F., De Blasiis M.R., Di Benedetto A., Fiani M., Use of Terrestrial Laser Scanner for Rigid Airport Pavement Management, Sensors, 2018, no. 1, p. 44, 2018 DOI: 10.3390/s18010044

• Applications in costal areas

De Giglio, M.; Greggio, N.; Goffo, F.; Merloni, N.; Dubbini, M.; Barbarella, M. Comparison of Pixel- and Object-Based Classification Methods of Unmanned Aerial Vehicle Data Applied to Coastal Dune Vegetation Communities: Casal Borsetti Case Study. Remote Sens. 2019, 11, 1416. https://doi.org/10.3390/rs11121416

 

Furthermore I suggest to specify the performance values for the described technologies, so that users can be helped in a survey project. For example accuracy together with the elaboration time play a major role in the survey project. I suggest to insert in cap 4 some quantitative reference to these discriminating characteristics.

Author Response

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Reviewer 4 Report

The article describes the possibilities of using 2D lidars for 3D laser scanning technology. 6 categories of prototypes and the problems encountered with their application were described.
The article lacked numerical values. First of all, what price range do the authors consider to be low-cost. In table A1 prices for commercial systems are presented: 2D lidar ranges from 500 to 42,000 CNY and for 3D lidar from 23,000 to 680,000 CNY. Are all commercial systems listed as high cost, what would be the cost of a low cost system?
The cost of the systems is influenced not only by the measuring range, but most of all by the metrological parameters. In table A1 it is worth adding what is the accuracy of determination of the coordinates of the points.
It is understandable that the more expensive the system, the more accurate the measurements are. What are the allowed measurement errors that the authors assume for the low-cost system?

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Reviewer 5 Report

This study reviewed the application of low-cost 3D laser scanning based on moving 2D lidars. While the study presented in this manuscript should draw the interest of the engineering and research communities, I cannot recommend the manuscript for publication in its current form because of the following considerations.

Technical considerations:

1-The Abstract does not clarify the novel horizons of the paper so that authors should include the joint innovative side of the reviewed papers in the Abstract. Please shortly identify the scientific problem, i.e. what is currently the research gap and how the reviewed papers improved it. Moreover, Authors are recommended to indicate specific consideration and future directions.

2- The level of English in several places within the manuscript does not meet the journal’s required standard. This paper has numerous grammar and language issues. The authors must improve English.

3- The introduction of the manuscript needs to be completely rewritten. This section is continuously stating that the 2D lidar is more economical than 3D laser scanning. However, the reviewer believes that these types of statements are not fair. Moreover, science is always evolving. The 3D laser scanner is a state-of-the-art instrument and a right alternative for traditional ways of inspection and surveying. I understand that the manuscript is trying to talk about the low-cost 3D laser scanning based on moving 2D lidars, however, the authors are suggested to present the background in this specific area stating the updated references in this area.

4-The structure of the manuscript is not well-organized. The introduction has not completely addressed the background of the study. The information given in Section 2, Overview of Principle, is unclear and sometimes questionable.

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