Small Target Radiometric Performance of Drone-Based Hyperspectral Imaging Systems

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

In this paper, the radiometric performance assessment on small targets was assessed for a fix mounted drone-based hyperspectral imaging system. My major concerns are as follows.

 1. The main contributions of this paper are suggested to be summarized in Section 1.

 2. The further work is suggested to be given in Section 5.

 3. The pros. and cons. of this paper should be summarized.

 

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

Here are some review comments for the manuscript titled "Small Target Radiometric Performance of Drone-based Hyperspectral Imaging Systems":

（1）----------(Section 2.1"Equipment Overview" and Section 3.1 "Experiment Overview"):

The manuscript provides a detailed description of the equipment used and the experimental setup. However, it would be beneficial to include more information about the calibration process of the hyperspectral imaging system and any potential sources of error that could affect the results. Additionally, the choice of Lambertian and point targets for the experiment should be justified in terms of their relevance to the study's objectives.

(2) ---------(Section 2.2 "Field Irradiance Measurement Theory" and Section 2.3 "Imaging Point Targets: Radiometric and Spatial Response"):

The manuscript presents a comprehensive theoretical background for the measurement of field irradiance and the imaging of point targets. It is recommended to provide a clearer explanation of how these theoretical concepts are applied in the context of the experiment and how they contribute to the assessment of the hyperspectral imaging system's performance.

(3)---------- (Section 4 "Results and Discussion"):

The article presents experimental results and discusses their impact on the performance of hyperspectral imaging systems. It is suggested that the comparison between point and Lambertian targets be expanded to include a discussion of the advantages and limitations of their use in evaluating system performance, respectively.

(4)---------- (Section 5 "Conclusions"):

The manuscript concludes with a summary of the findings and their implications for drone-based hyperspectral imaging systems. It would be beneficial to include suggestions for future research directions based on the results of this study, such as the development of improved calibration techniques or the investigation of alternative target types for performance assessment.

Comments on the Quality of English Language

The authors are encouraged to carefully check English writing of the manuscript.

Author Response

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Author Response File: Author Response.docx

Reviewer 3 Report

Comments and Suggestions for Authors

The authors proposed an assessment method for radiometric performance  on small target based on UAV. Although this method may be of great application values, there are several major concerns that the authors should consider clarifying:

1. To my understanding, the method proposed in this study is highly similar to the SPARC technique proposed by Schiller and Silney (Ref. [15] in this paper) almost 15 years ago. Did the authors just transfer the same method to the UAV platform? What are the differences? What is the major novelty of this study?

2. SPARC method was proposed to remove the bias between multiple satellite-based sensors. Does the method proposed in this study designed or tested in the same way? Could the method be tested under multiple sensors? Answering these questions can help the readers re-produce the proposed method.

3. As I mentioned above, the radiometric calibration is of great application values, as it can be used to infer the remote sensing reflectance and identify the targets, i.e., vegetation, oil spill, harmful algae, mineral, etc. The author should add some discussions in the Introduction on the significance and application of radiometric calibration so as to clearly indicate the application values of this method. 

4. The shapes of several radiation spectra shown in the paper are quite jag-saw (e.g., Fig. 8, 9, 11, 13, etc.), which is kind of odd especially under solar radiation. Are they the actual radiation from the targets or caused by instrumental noise?

Author Response

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Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

The authors have well addressed my comments!