A Tree Ring Measurement Method Based on Error Correction in Digital Image of Stem Analysis Disk

Round 1

Reviewer 1 Report

The manuscript “A Tree Ring Measurement Method Based on Error Correction in Digital Image of Stem Analysis Disk” reports the results of study to explore the tree ring radius measurement and error correction using the digital images of stem analysis disk. In my opinion, an article in this form is not acceptable and significant additions and modifications are needed. At first, it’s more like a methodological tool for working with digital images for steam disk analysis than a scientific article. As for the article, it’s missing a several important things.

This is the second question to be asked: the authors need to clearly highlight where and how their work is original in comparison to earlier papers; such an originality is a prerequisite to publication.

• In this article, I miss the well-described aim of this study. Is this a new method?Is this a new computer app for measuring tree rings? A apps for measuring rings wight from a image are definitely not one.
• In the study was used coniferous wood with good visibility of annual rings. And what about deciduous wood that does not have such bright annual rings? Could this method be used?
• The material and method section is too long (6 pages), hard to read and includes a number of statements that are unclear. It definitely needs to be restructured.
• There is no discussion section in the article. It is necessary to compare your results with other authors results or to compare different methods.
• Conclusions must be improved, because at the moment it’s more like abstract. Conclusion must show what results are the best and what new was found in this study.

However, the current draft in my opinion needs to be further developed before it is ready for publishing. In addition in above, the text is not easy to read, with long and complicated sentences and several awkward formulations.

Author Response

Dear reviewer:

Thanks again for your constructive comments and suggestions on our manuscript entitled “A Tree Ring Measurement Method Based on Error Correction in Digital Image of Stem Analysis Disk”. (Manuscript ID: forests-1154327). We have tried our best to revise the whole manuscript according to your kind advices and detailed suggestions. We sincerely hope that this revised manuscript has addressed all your comments and suggestions. Enclosed please find the responses to the referees.

Yours sincerely,

WenJie Zhang

Comments and Suggestions for Authors

Point 1：It’s more like a methodological tool for working with digital images for steam disk analysis than a scientific article. As for the article, it’s missing a several important things.

Response：Thank you very much for your comments and we totally understand the concern. This may be due to the unscientific structure of the manuscript and the lack of some important descriptions in the content. We revised the introduction and the conclusion, adjusted the materials and methods, supplemented the discussion and the unclear content was rewritten according to your comments and suggestions. Thank you for your suggestions and we have tried our best to revise the article. We hope the revised article can be approved.

Point 2：The authors need to clearly highlight where and how their work is original in comparison to earlier papers; such an originality is a prerequisite to publication.

Response：Thanks for your constructive suggestion, which is highly appreciated. As for the novelty, it is well-known that there have been studies using image processing technology to measure ring width in the past, and this method greatly facilitates the measurement of ring width. However, when the digital camera is used for close range shooting, the edge of the image will produce geometric distortion, but previous studies rarely mentioned this measurement error, or just point out the existence of this measurement error, but not to correct it. In this study, we used a portable digital camera to take the samples of tree rings, so we take this error into account.

We build a regression model of ring radius based on error correction to reduce the error, improve the measurement accuracy, and this method has been proved to be applicable to deciduous tree species. At the same time, some of the instruments or systems studied in the past are complicated and expensive. So in this paper, we choose Open CV to measure ring width, it’s an open source computer vision software library which is cheaper and easier to operate. Thanks again to the reviewer on suggesting to further improve this manuscript, we have studied comments carefully and have made corresponding corrections in the introduction part of the article to emphasize our innovation and originality. Please refer to lines 92-106 for details. We hope meet with approval.

Point 3：In this article, I miss the well-described aim of this study. Is this a new method? Is this a new computer app for measuring tree rings? Apps for measuring rings width from an image are definitely not one.

Response：We are sorry that the purpose of our research was not clearly described in the manuscript. Please allow me to explain the purpose of our research here. Because when the width of the ring is measured by image, the geometric distortion will occur on the edge of the image, which will affect the accuracy of the measurement. The purpose of our research is to explore a new method to reduce the measurement error caused by the geometric distortion of the image and improve the measurement accuracy. So, in the process of measuring the ring width, we established an error correction model to eliminate this error. On the other hand, we know that there is more than one existing ring width measurement system, and there are high-precision professional ring measuring instruments, but these professional systems and instruments are expensive, not portable, and have high requirements for the measurement environment. At the same time, some ring width measurement methods based on image processing are only suitable for coniferous tree species with clear ring, but not for deciduous tree species, or the measurement accuracy needs to be improved. In view of this situation, and based on the research method of this paper, we designed a disk measurement system. This ring width measurement system based on Open CV is cheap and easy to operate, and the accuracy meets the requirements. The above is the purpose of our research. In view of your suggestion, we have improved the abstract and introduction of the article to clarify my research purpose and significance. Please refer to lines 13-31 and lines 92-106 for details.

Point 4：In the study was used coniferous wood with good visibility of annual rings. And what about deciduous wood that does not have such bright annual rings? Could this method be used?

Response：Thank you very much for your question, we agree that more study about deciduous trees would be enrich the content of this paper. We have collected more data of deciduous trees and carried out a series of experiments, and the results show that our method is also suitable for deciduous tree species. The detailed experimental process and results are written in the second part of discussion section. The title of the second part is “Analysis of tree species suitable for the model”, please refer to lines 394-420 for details.

Point 5：The material and method section is too long (6 pages), hard to read and includes a number of statements that are unclear. It definitely needs to be restructured.

Response： As the material and method section is too long, we accepted the advice and reduced some content. At the same time, we have revised some unclear statements in the content, the material and method section of this paper is reconstructed. Please refer to lines 107-232 for details.

Point 6：There is no discussion section in the article. It is necessary to compare your results with other author’s results or to compare different methods.

Response：We are grateful for the suggestion. In order to make the article more complete and clear, we supplement the discussion section of the article. In the meantime, we compared our results with other author’s results in the first part of the discussion. The title of the first part is “Measurement comparison with mainstream research methods”, please refer to lines 367-393 for details.

Point 7：Conclusions must be improved, because at the moment it’s more like abstract. Conclusion must show what results are the best and what new was found in this study.

Response：Thank you for underlining this deficiency. The conclusion was revised according to the suggestion, in this part, we try to highlight the research results and innovation, and make a brief introduction to the follow-up application of the research. Please refer to lines 421-437 for details.

Point 8：The current draft in my opinion needs to be further developed before it is ready for publishing. In addition in above, the text is not easy to read, with long and complicated sentences and several awkward formulations.

Response：We supplement the research content of the article according to the suggestions, and we are very sorry for the mistakes in this manuscript and inconvenience they caused in your reading. The manuscript has been thoroughly revised and edited by a native speaker, so we hope it can meet the journal’s standard. Thanks so much for your useful comments.

Author Response File: Author Response.docx

Reviewer 2 Report

This paper is of significance to specialists in tree ring analysis, and to forest growth and climate change modelers in general. It presents a much simplified method that will be very useful to those interested in tree ring analysis.  I am thinking also of students in forestry labs.  It is easily understood by readers and well presented, except it would benefit from a solid review by a native English language speaker who is competent in technical writing.

1. Please try to explain coding terms so the "novice" can understand what the programming does.
2. Insert lines of code in a way that separates them from the body of text,
   e.g. indent and space above and below. This makes it easier to read.
3. Line 83, provide reference to Open computer vision software library.
4. Define Terms where they appear first, put into the figure caption
5. Fig. 3: Schematic is clear and useful, except schematic does not show a feed back of preprocessed images  into the analysis.
6. Line 175-76 spelling: Not everyone interested in this paper will know code, and () can have different meanings for different software, so if you use coding in the text, at least explain the terms, e.g. (), for the larger audience.
7. use the same form of the lower case Rho as in the above equation.
8. line 273: The meaning is unclear and the sentence has no verb.
9. line 348: Spelling heteroscedasticity
10. Fig.8: Was a test for heteroscedasity performed? I ask because it seems heroscedastic to this observer. 
11. Fig. 9: figures with the caption should be interepetible on their own. Define u1 and u2 in the caption.

Author Response

Dear reviewer:

First of all, thank you very much for your encouragement. And thanks again for your constructive comments and suggestions on our manuscript entitled “A Tree Ring Measurement Method Based on Error Correction in Digital Image of Stem Analysis Disk”. (Manuscript ID: forests-1154327). We have tried our best to revise the whole manuscript according to your kind advices and detailed suggestions. And the manuscript has been thoroughly revised and edited by a native speaker. We sincerely hope that this revised manuscript has addressed all your comments and suggestions. Enclosed please find the responses to the referees.

Yours sincerely,

WenJie Zhang

Comments and Suggestions for Authors

Point 1：Please try to explain coding terms so the "novice" can understand what the programming does.

Response：Thanks for your suggestion. We have explained the coding terms and put them in Appendix A. Please refer to lines 447-472 for details.

Point 2：Insert lines of code in a way that separates them from the body of text, e. g. indent and space above and below. This makes it easier to read.

Response：For ease of reading, we separate the code from the text and put it in Appendix A, meanwhile, the space of the code line paragraph is adjusted. Please refer to lines 451,455,461-462, and 468 for details.

Point 3：Line 83, provide reference to Open CV computer vision software library.

Response：As for the concern, the reference to Open CV computer vision software library has been supplemented in the revised manuscript. Please refer to lines 95-97 for details.

Point 4：Define Terms where they appear first, put into the figure caption.

Response：Thank you very much for your advice. We have checked that all the terms have been defined and added the undefined ones in the title of the figure. Please refer to lines 179-180 for details.

Point 5：Fig. 3: Schematic is clear and useful, except schematic does not show a feedback of the preprocessed image into the analysis.

Response：Thanks for your careful checks. We modified the Figure 3 and added the feedback of the preprocessed image into the analysis. Please refer to line 178 for details.

Point 6：Line 175-76 spelling: Not everyone interested in this paper will know code, and () can have different meanings for different software, so if you use coding in the text, at least explain the terms, e.g. (), for the larger audience.

Response：We explained the parameters of the code and put them in Appendix A. Please refer to lines 447-472 for details.

Point 7：Use the same form of the lower case Rho as in the above equation.

Response：We have modified R, a, b, o in the text to correspond to the lower case form in the equation. Please refer to lines 185-198 for details.

Point 8：Line 273: The meaning is unclear and the sentence has no verb.

Response：we accept the advice，and the sentence has been adjusted. Please refer to line 234 for details.

Original sentence：Tree ring radius extraction

Modified Sentence：Obtain the uncorrected ring radius

Point 9：Spelling heteroscedasticity

Response：We are very sorry for our careless mistakes and we have corrected the spelling of heteroscedasticity in line 314.

Point 10：Fig.8: Was a test for heteroscedasticity performed? I ask because it seems heteroscedastic to this observer.

Response：We appreciate for your valuable comment, and we feel sorry for our carelessness. We supplement the heteroscedasticity test and find that the model does have slight heteroscedasticity, the previous incorrect description has been corrected in the manuscript. At the same time, we make a supplement to the correction of heteroscedasticity, please refer to lines 311-321 for details.

Point 10：Fig. 9: Figures with the caption should be interpretable on their own. Define u1 and u2 in the caption.

Response：The definition of variables u1 and u2 are repositioned and placed in the caption. Please refer to lines 341-345 for details.

Author Response File: Author Response.docx