Simulation of Reflectance and Vegetation Indices for Unmanned Aerial Vehicle (UAV) Monitoring of Paddy Fields
Round 1
Reviewer 1 Report
The revision has done based on previous reviewers’ comments thoroughly and reasonably. Please accept this manuscript as it is.
Author Response
Thank you for your approval.
Reviewer 2 Report
You addressed the most of my previous comments. Presently, I would only appreciate if you add 1) some infos concerning number and distribution of GCPs and 2) some discussions concerning significance of dfferences between simulated and estimated for both spectral indices and bands. Adding some appropriate references could be enough. few punctual comments are within the revised pdf.
Comments for author File: 
Comments.pdf
Author Response
1) some infos concerning number and distribution of GCPs.
The number and distribution of GCPs was described (L154).
2) Some discussions concerning significance of differences between simulated and estimated for both spectral indices and bands.
We discussed about the difference (L269). The reference proposed by the reviewer was added ref[23].
Reviewer 3 Report
The objective of this paper is very interesting and important for applications of UAV flights in crop growth monitoring. And this topic is related to Remote Sensing.
This paper seems that has been revised at least one time. It can be accepted after minor revisions as below.
DETAILED COMMENTS
Line 153 - 168, is the illumination condition stable during each flight? I mean that does the diffuse ratio at the start and end of UAV flights keep the same values as you calculated using Erbs method? Figure 3 I suggest you change the symbols because it is hard to read. Line 52, vegetation indices, not indices Line 72, status
Author Response
>L153-168 is the illumination condition stable during each flight?
The radiation condition was assumed to be constant during the flight because it was relatively stable with respect to the solar radiation condition (L169).
>Symbols in Fig. 3.
We increased the size of symbols in Fig 2-4 to distinguish the symbols.
>L52 and L72
The words were revised.
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 research article “A simulation of reflectance and vegetation indices for unmanned aerial vehicle (UAV) monitoring in paddy fields” is an interesting and impactful article discussing how the emerging UAV technology for crop imaging can be used scientifically. The authors made a good point that few previous studies have been discussing this very topic and most of UAV-related researches were not discussing the reflectance appropriately. So this topic is very meaningful for the society and can have good impact for UAV imaging field.
Overall the methods of the study are scientific, and the analysis and results are reasonable and insightful. However, there are some points in the introduction that the authors need to clarify better before this article can be accepted by the journal.
1). Line 58, the author should talk about why the rice was selected for this study object of this research but not other crops. By clarifying this, this study can provide guidance for the future studies.
2). From line 74, the authors started talking about FLiES model over other radiative transfer model. The authors really should cite more papers and compare popular models and clarify this this model is selected over others.
Reviewer 2 Report
Although the manuscript is presented in the technical note form, it suffers from a series of flaws that force me to reject it. The work is too simple for a journal as Remote Sensing and the scientific soundness is too low. In my opinion the reason why the author intended to do this kind of study is not well motivated and described. Although I did not consider this study sufficiently adequate in terms of novelty and scientific soundness, the author should better justify the motivation of this work and the potential effects on the scientific community. In recent years, monitoring vegetation indexes has become very simple and achievable without effort either in terms of cost or in terms of scientific effort (satellite, UAVs), why simulate these indices?
Moreover, the results are poorly presented and remain too simplistic,
Figure 1 is useless and does not explain the model taken into consideration but a generic model
The other figures are too many and unreadable
Even if the author reports the references on the model used, I think that some further details would have to be inserted
Abstract is not complete, a sentence where UAV campaigns have been carried out to verify the reflectance is missing, not hard numbers of results and conclusion sentence is missing
In M&M it is not clear if a radiometric correction has been made
A reference on the calculation of the LAD is missing
Results are difficult to read
Reviewer 3 Report
The paper is about simulation by FliES model of canopy reflectance of paddy fields. It well fits the goals of Remote Sensing Journal and the content interesting for the scientific community. Nevertheless, in my opinion, the paper is still far away to be published since many very critical issue are missing to make results reliable enough.
I’ve pointed out the main problems within the attached pdf file (notes).
First of all the state of the art of this topic and the role of the paper within this context is not well figured out. Introduction must be heavily improved making clearer the importance of this research.
Moreover, I find that all needed info concerning UAV image processing is missing. No info about image block bundle adjustment and positional accuracy of the resulting multispectral orthomosaic from PIX4D software. Any Ground Control Points were used? If yes how were they collected? GNSS? Accuracy? This info is basic to ensure consistency about UAV derived and ground measures, that, similarly are not qualified at all in terms of georeferencing accuracy.
Additionally, no info is given concerning UAV image calibration and atmospheric correction. Calibrated panel? Empirical line ? Radiative transfer model? This is basic if one want to compare simulated data with a reference dataset (UAV is the reference?). Expected accuracy of computed at-the ground reflectance ?
I feel that, especially concerning the red band, showed variations could not be appreciated by UAV measures!
Technical terms must be refined, together with English style that, somewhere sounds very diffivult to be understood.
Finally, I have to reject the paper at this stage, suggesting a re-submission after a very deep and important revision.
SEE also ATTACHED PDF file!
Comments for author File: Comments.pdf
