Development and Testing of a UAV-Based Multi-Sensor System for Plant Phenotyping and Precision Agriculture
Round 1
Reviewer 1 Report
- Figure 7 : Figure caption "The customized device to record atmospheric conditions (highlighted by red rectangle) were mounted between the calibration targets" were---seems to be "was"
- Line 366 "The testing field was prepare prior to" prepare--should be "prepared"
- Figure 20. Canopy volume （m2)--why not m3 ?
Author Response
- Figure 7 : Figure caption "The customized device to record atmospheric conditions (highlighted by red rectangle) were mounted between the calibration targets" were---seems to be "was"
Response: Thanks for the reviewer’s suggestion. The error was corrected.
- Line 366 "The testing field was prepare prior to" prepare--should be "prepared"
Response: Thanks for the reviewer’s suggestion. The error was corrected.
- Figure 20. Canopy volume （m2)--why not m3 ?
Response: Thanks for the reviewer’s suggestion. The error was corrected.
Reviewer 2 Report
The manuscript was very interesting and present the scientific way for crop biophysical aspect studying. The manuscript is well designed and presented logically. I have no specific comments or questions just might need some minors checking in the text and present a little about application for other crop types and limitations of devices such a crop row distance and working environment.
Author Response
The manuscript was very interesting and present the scientific way for crop biophysical aspect studying. The manuscript is well designed and presented logically. I have no specific comments or questions just might need some minors checking in the text and present a little about application for other crop types and limitations of devices such a crop row distance and working environment.
Response: Thanks for the reviewer’s positive review. We have added the following sentences in the discussion to show the application of our systems and limitation of the device.
Line 543-550: Our system is not tied to specific crops and can be used for different fields including row crops and vineyard, with no specific requirement for the field layout (e.g., row spacing). For example, the UAS can be used to collect multispectral image to detect tomato spot wilt disease in peanuts and color images to measure the blueberry bush morphological traits [19,55]. Other potential applications include forestry and environment monitoring. To ensure good image quality, it is preferred to collect images under uniform lighting conditions, such as a clear sunny or overcast day. It is also preferred to collect data with no strong wind since the movement of the crops can affect the accuracy of the 3D reconstruction from images and LiDAR scans.
One reference was added
Patrick, A.; Li, C. High throughput phenotyping of blueberry bush morphological traits using unmanned aerial systems.Remote Sensing2017,9, 1250.
Reviewer 3 Report
The paper develops "an unmanned aerial system that integrates cameras (RGB, multispectral and thermal) and a LiDAR sensor".
Properly the paper presents, as the authors say in the conclusions, "a design of a multisensor data acquisition system with ROS for unmanned aerial systems that can be used to plan phenotypes".
Please change the title
The S100 has been discontinued and also probably the DJI 600. Is it not possible to use the system on another UAV?
It should indicate the minimum features that a UAV should have in order to work on another UAV.
It is also important to add some references in some technical section (e.g. 3.1 , 4,2,1, 4,2,4, etc).
The authors say (several times) that the system is opne source but they use metashape (4.1) (a proprietary software). Isn't it possible to develop with OpenSFM (https://www.opensfm.org/) ?
Authos says " LiDAR scans can be assembled into point clouds using the position and pose of the scans ...... Since the current UAS does not have an RTK-GNSS and IMU, LiDAR data was not used in this study. However, LiDAR data processing was integrated as part of the overall data processing pipeline and is prepared for additional pose and attitude data."
Please add a comment on the changes to be added to be able to work with LiDAR data or write a little less of this sensor
Overall the paper is well written and it is technically sound, although the indicated corrections need to be made.
Author Response
- The paper develops "an unmanned aerial system that integrates cameras (RGB, multispectral and thermal) and a LiDAR sensor".
Properly the paper presents, as the authors say in the conclusions, "a design of a multisensor data acquisition system with ROS for unmanned aerial systems that can be used to plan phenotypes".
Please change the title
Response: The goal of this paper is to develop a UAV system for plant phenotyping, including the data acquisition system and the UAV. We have modified the sentence in the conclusion.
Line 561-562: “This paper presented a design of a multi-sensor unmanned aerial systems with ROS that can be used for plant phenotyping and precision crop management.”
- The S100 has been discontinued and also probably the DJI 600. Is it not possible to use the system on another UAV? It should indicate the minimum features that a UAV should have in order to work on another UAV.
Response: the data acquisition system can be used for different UAV. We have added the following sentence.
Line 119-121: “The DAS also can be carried by other rotatory UAVs with adequate payload to carry the DAS. Connection brackets may need to be redesigned to fit the specific drone.”
- It is also important to add some references in some technical section (e.g. 3.1 , 4,2,1, 4,2,4, etc).
Response: We have added the following reference for 3.1
Zhang, Z. A flexible new technique for camera calibration. IEEE Transactions on pattern analysis and machine666intelligence2000,22, 1330–1334.
After careful review, we found that the vignetting correction was integrated as part of the radiometric calibration for the multispectral camera, so we added the following sentence to clarify that and modified Figure 6 accordingly.
Line 210: “For the multispectral image, the vignetting correction is integrated as a part of the radiometric calibration.”
- The authors say (several times) that the system is opne source but they use metashape (4.1) (a proprietary software). Isn't it possible to develop with OpenSFM (https://www.opensfm.org/) ?
Response: Currently, we used metashape for image stitching and reconstruction since it has been widely used in research community and yields good results. In this study, we only open-sourced the design of the data acquisition system. The data processing pipeline was not open-sourced, but we used open-source software to implement the pipeline except the image stitching and 3D reconstruction. In the future we can use OpenSFM to generate orthomosaic and 3D model so the whole data processing pipeline can be streamlined.
The following sentence was added to discussion.
Line 557-559: “The data processing pipeline can be improved by replacing the commercial software Metashape with open-source software such as OpenSfM (www.opensfm.org) to make it streamlined”
- Authos says " LiDAR scans can be assembled into point clouds using the position and pose of the scans ...... Since the current UAS does not have an RTK-GNSS and IMU, LiDAR data was not used in this study. However, LiDAR data processing was integrated as part of the overall data processing pipeline and is prepared for additional pose and attitude data." Please add a comment on the changes to be added to be able to work with LiDAR data or write a little less of this sensor
Response: The following sentence was modified
Line 280-282: “However, the LiDAR data processing was integrated as part of the overall data processing pipeline and is ready for the additional positional and attitude data, for example, by using an RTK-GNSS and IMU to get the precise location and orientation of each LiDAR scan [45].”
Overall the paper is well written and it is technically sound, although the indicated corrections need to be made.
Author Response File: 
Author Response.docx
Round 2
Reviewer 3 Report
The authors state :
The aim of this work is to develop an unmanned aerial vehicle system for plant phenotyping, including the data acquisition system. We have modified the sentence in the conlusion."
In my opinion, it is mandatory to modify the title: The paper does not present anything about the development of a drone (fundamental part of a UAV system).
Author Response
We thank the reviewer for the suggestion. We have modified the title as follows: "Development and testing of a UAV-based multi-sensor system for plant phenotyping and precision agriculture" and hope the reviewer find it satisfactory.
