Noise Analysis for Unbiased Tree Diameter Estimation from Personal Laser Scanning Data

Round 1

Reviewer 1 Report

Personal laser scanning devices employing Simultaneous Localization and Mapping (SLAM) technology have useful in forest mensuration and inventories. So, it is valuable to clarify the inherent stochastic noise related to device. However, just acquired a few data in single scene is not sufficient to evaluate the characteristics and distribution of errors. It is recommended that the relevant data be further supplemented in order to obtain more reliable conclusions.

1) The key points and detailed results should be added to the part of abstract, such as Specific numbers and important conclusions about the DBH.

2) The objective of the manuscript is to evaluate the inherent stochastic noise, the literatures about errors source and evaluating methods should be added to the part of introduction.

3) Is the error you mentioned just related to the device you are using or is it common? In previous study, how to deal with the inherent stochastic noise mentioned in your manuscript.

4) Normally, it is very important to consider the size of samples and the representativeness of the data to evaluate the noise of data. In your manuscript, the results were derived from just a few data acquired from single scene. Therefore, there is reason to doubt the reliability and rationality of the results.

Minor editing of English language required

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

This is an interesting manuscript about the errors of tree diameter measurements when using mobile laser scanning and the SLAM technique. Overall, the paper is well written although I had some difficulties of following parts of the methods description. My only major concern is that I would like to see parts of the methods' description improved (see detailed comments below).

Detailed comments:

1) Abstract: Avoid using the term "deviance" which has a technical meaning in statistics, which I think is not intended here. The term "difference" might be more appropriate?

2) The objectives of the manuscript are poorly described. Please enhance so that it becomes clearer what was the focus of the study.

3) Section 2.4 seems to describe the core methods adopted by the authors. However, I find this section difficult to follow. Thus, I hope the authors could improve the clarity of this section.

4) Likewise, I find the description of the simulation study performed to evaluate the effect of individual scan lines difficult to follow. I hope this part of the text could also be improved.

The results are interesting and informative!

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Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

Abstract

Please avoid using (we, our, and us), use the passive voice. Please check the paper.

Please rewrite the abstract and consider the following points:

Please quantify the accuracy of the suggested approach.

Summarised the suggested approach.

Please define all used abbreviations such as TLS, RANSAC,  LiDAR, etc, please check all paper.

 Introduction

The more recently cited paper is dated 2022. The bibliography needs to be updated using recent references such as:

Tarsha Kurdi, F., Lewandowicz, E., Shan, J., Gharineiat, Z. 2024. Three-dimensional modeling and visualization of single tree LiDAR point cloud using matrixial form. IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, vol. 17, pp. 3010-3022, 2024, doi: 10.1109/JSTARS.2024.3349549.

Dengsheng Lu & Xiandie Jiang, 2024. A brief overview and perspective of using airborne Lidar data for forest biomass estimation, International Journal of Image and Data Fusion, doi: 10.1080/19479832.2024.2309615.

Knowing that there are hundreds of papers published every year about similar topics.

 Line 72: you said, “tree diameters” do you mean “tree footprint diameters”?

Please highlight the contributions and novelties in this paper.

Materials and Methods

Please don’t put two section titles consecutively, you must add a transition paragraph between them, please check all the papers.

Please add a flowchart of the suggested approach, and underline the input and the output.

Research area

Table 1: Please define abbreviations used in this table under the table.

Data processing

Please replace the term “processing” with an accurate word that describes the target procedure.

Line 125: what do you mean by “segmented and cleared “? Do you mean “extracted and filtered”?

 Line 135:

1Center: remove “1”.

cross-section of what? You can add a figure to illustrate what you mean.

What are the used parameter values in RANSAC?

circle center fitted with RANSAC: this is a mistake because the RANSAC paradigm is used to recognize geometric objects but not for fitting them, to fit one detected geometric object by RANSAC, we should apply the least squares. Please read :

Tarsha Kurdi, F., Landes, T., Grussenmeyer, P. 2008. Extended RANSAC algorithm for automatic detection of building roof planes from Lidar data. The Photogrammetric Journal of Finland. Vol. 21, n°1, 2008, pp.97-109.

Line 137: perimeter points of what? Please write clear and transparent sentences.

Please cite a reference for “Cyclic LOESS”.

Figure 2 caption: the same questions:  perimeter of what? And cross-section of what?

Figures 2 b and c - you say: “TLS points and the perimeter model in the polar coordinates.” You confuse between polar coordinates and cartesian space. In Figure 2b, you represent the polar coordinate in cartesian space (parameter space), that is why it is not polar representation, then we cannot call it polar coordinates.  Please see the paper:

Tarsha Kurdi, F., Landes, T., Grussenmeyer, P. 2007. Hough-transform and extended RANSAC algorithms for automatic detection of 3d building roof planes from Lidar data. ISPRS Workshop on Laser Scanning 2007 and SilviLaser 2007, Espoo, Finland, Sept. 12-14th. ISPRS International Archives of Photogrammetry, Remote Sensing and Spatial Information Systems. Vol. XXXVI, Part 3 / W52, 2007, pp. 407-412.

 Lines 147 to 157: add requested equations.

173: point, the corresponding trajectory segment was recorded.: how?

Please determine the input and the output of each procedure.

I don’t understand what you are talking about (all tree point clouds, or the trunk only) what are the input and the output of each procedure? You talk in a general way, the text is not transparent. The reader doesn’t know what you think about, if the text is vague, he will not understand it.

How did you get the ground truth?

You suppose that your objects are circular, but that is not the case.

Line 281: it is Figure 6, not 1.

The paper in this form cannot be accepted, because it contains scientific mistakes, the paper is vague, and not enough figures and flowcharts are provided. Your hypothesis is not always applicable, RANSAC capacity is limited to detect circles (you exaggerate a lot about its efficacity). 

Minor editing of the English language is required. 

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 3 Report

The paper looks better.

Minor editing of the English language may be required.