A Bridge Damage Visualization Technique Based on Image Processing Technology and the IFC Standard
Round 1
Reviewer 1 Report
The paper presents research on an interesting and popular among Structural Health Monitoring specialist issue – the detection of damages to structures thanks to vision-based methods.
Authors propose of the accurate visualization of crack and void damages relating it to the IFC standard; their successful attempts may be considered original. Thus, this original paper addresses a certain gap in this field.
The use of the word "disease" in the text about the SHM seems to be not very accurate. There are very few texts that use this terminology, but the vast majority of texts, both scientific and technical, refer to the word "damage". It is a traditional nomenclature, which ensures proper systematization of the text and should help to improve its search, and thus should result in easier access to specialists dealing with this issue. Suggests considering replacing the word "disease" with "damage" in the title and throughout the text.
The text is preceded by a well-developed, though based on a short but accurate and sufficient selection of literature, state-of-art report.
The research is well-designed and executed, the methodology is carefully and clearly explained, and the results are well-described and discussed.
The conclusions are generally well-constructed.
The authors indirectly indicate the perspective of further research linking the proposed method with the BIM environment, which is certainly positive.
The paper is generally edited on a good level, however, some typo errors are encountered in the text. Please verify the spelling of superscripts. The whole text shall be revisited, carefully checked, and corrected.
Authors sometimes use non-standard nomenclature in the text and tend to build complex sentences, which makes the text difficult to understand. I propose a detailed verification of the text in terms of the English language.
Author Response
Thank you for your valuable comments on our manuscript. We apologize for any inconvenience caused by the typos and non-standard nomenclature that you mentioned in your review. We have carefully reviewed and revised the introduction's second paragraph, sections 2.1 (first and fourth parts), 4.1, 4.2, and the last paragraph of 4.4 in terms of grammar and expression. Additionally, we have replaced all instances of the word 'disease' with the word 'damage' throughout the paper.
We appreciate your constructive feedback, and we hope that the revised manuscript meets your expectations. If you have any further comments or suggestions, please do not hesitate to let us know.
Thank you again for your time and effort in reviewing our manuscript.
Author Response File: 
Author Response.docx
Reviewer 2 Report
For common bridge diseases, the authors propose a visualization method for bridge diseases based on image processing technology and IFC standard description. Based on an existing cable-stayed bridge as the engineering background, the existing cutting-edge technology is used to process and analyze the collected disease images to obtain disease information; Based on IFC standards, the Revit bridge model was established to visualize and store bridge diseases. All in all, the topics in this paper are of practical value and rich in content. However, the following changes need to be made in the paper:
1. The second natural paragraph of the introduction section shows a large amount of literature piling up, and an overall lack of logic, so we suggest revising it.
2. The literature cited in line 60 does not correspond to its author. Please check whether other literature corresponds to its author by yourself.
3. It is suggested that the formulae in the text should be supported by corresponding literature and the symbols in the formulae should be explained.
4. The content expressed in lines 230-232 is not visually reflected in Figure 6.
5. The content of lines 279-280 is repeated with that of line 278, and the layout and description of the text should be refined.
6. The picture in line 344 is incorrectly labeled and should be amended to "Figure 17".
7. Suggest centering the image and its title in the text.
8. The description of the content of lines 246 and 352 in the text is unclear.
9. The title format of line 86 is not consistent with the title format of line 153, so the title format should be unified.
10. There is a problem with the format of the units in lines 298 and 299, please check the formatting problems of other units in the text by yourself.
Comments for author File: 
Comments.pdf
Author Response
Thank you for your comments and suggestions on our manuscript. We have made the following modifications based on your feedback:
1.We revised the second paragraph of the Introduction to improve the overall logical flow.
2.We checked and updated the reference list to ensure it aligns with the authors.
3.We added corresponding references to the formulas and provided further explanations.
4.We corrected the image numbering in the third paragraph of section 3.2, changing Figure 6 to Figure 4.
5.We revised the wording in the third paragraph of section 4.2.
6.We corrected the labeling error in Figure 17.
7.We centered the images and their captions.
8.We revised the fourth paragraph of section 3.2 and the last paragraph of section 4.4.
9.We updated the title format in section 2.2.
10.We revised the unit format in the fourth paragraph of section 4.2 and checked the formatting of other units.
Thank you for your valuable feedback, which has helped to improve our manuscript. If you have any further comments or suggestions, please do not hesitate to let us know.
Thank you again for your time and effort in reviewing our manuscript.
Author Response File: Author Response.docx
Reviewer 3 Report
The paper describes a procedure to include cracks as evidenced from processed images into a bridge solid model, exploiting the industry foundation classes (IFC) standard. Potentially, it is a way to digitize a bridge infrastructure in view of its lifecycle assessment. The paper is unclear in some parts. I had no access to Appendices A and B.
The following acronyms are used before being defined: PSO, SSA (Introduction), PE (line 268).
The sentence at lines 267-273 is badly written and/or with wrong punctuation.
Line 282. What does it mean “They were zooming in”?
What exactly do you mean by “skeletonization”?
Lines 282 and 294. I don’t believe that the expression “The pixel of the whole image is…” is correct English. A pixel is an elementary part of a raster image.
At line 287 you mention “the difference between the calculated and actual sizes”. What is the “actual” size for you? Did you measure the crack by other methods? Or you measure the crack size directly from the original image, let’s say from image 10 (left)? In the latter case, I would argue about the “actual” size.
Line 259. What is the meaning of “The main beam is of plate structure…”?
Section 4.3 seems a user manual, not a discussion about the rationale of the procedure or of valid issues related to it.
In Section 4.4 there is a de-featuring step, which is in partial contradiction with the accuracy of the image processing step. This de-featuring step appears arbitrary, whilst it is important. What is the rationale behind your choice?
I understand that the procedure requires a learned user intervention. So, in case of multiple cracks it would be a lot of work. Are there automatic steps in the procedure?
It is unclear to me how to identify the crack depth in the concrete bulk when you start from a planar image. Do you combine several images? It is not written in the paper.
Author Response
Thank you for your comments and suggestions on our manuscript. We have made several modifications based on your suggestions, which are as follows:
1.We have provided explanations for the abbreviations used in the second paragraph of the Introduction and the first paragraph of Section 4.2.
2.We have revised the first paragraph of Section 4.2.
3.We have made revisions to the third paragraph of Section 4.2.
4.Skeletonization is a process in which a shape or object is transformed into a simplified, one-dimensional representation known as a skeleton. The skeleton is a thin, simplified version of the original shape, which retains only the main structural features of the object while discarding its thickness and other details.It helps in the analysis and recognition of shapes and objects by reducing their complexity and representing them in a simpler form.
We have briefly introduced skeletonization in Section 2.1, Part 4 of the paper.
5.We have made revisions to the fourth paragraph of Section 4.2.
6.The actual size mentioned by us is the size measured in the field, which has been explained in the third paragraph of Section 4.2.
7.We have made revisions to the language used in the first paragraph of Section 4.1.
8.The bridge model is crucial for visualizing bridge damage and lays a solid foundation for establishing damage models. Section 4.3 describes the process of creating a cable-stayed bridge model in Revit and provides step-by-step instructions for creating various components. These instructions help readers understand the process and methods of creating these components and provide guidance on how to use Revit to create models. Although the content of this section may not be directly related to the main topic, establishing damage models is crucial. Therefore, Section 4.3 is of significant importance to the completeness and feasibility of this paper.
9.Accurate image processing directly affects the accuracy of obtaining damage data and building models based on this data. However, selecting too many feature points during the feature point extraction process can increase the difficulty of subsequent modeling. To balance accuracy and simplicity, we chose relatively fewer feature points, which helps to simplify the complexity of the damage model without significantly affecting the accuracy of the damage data. Although this step may seem arbitrary, it is a well-considered and reasonable choice. Therefore, we believe that this step is necessary and can improve the efficiency of building bridge damage models.
10.Currently, there are no automated steps presented in this paper. However, we are actively researching automated methods and have made some progress. If there are any relevant outcomes, we will publish a paper to share our research in a timely manner.
11.I'm sorry, this paper did not explore how to determine the depth of cracks inside concrete blocks from 2D images. The depth was only set in the crack model to make it more realistic. Thank you very much for pointing out this issue. We will continue to improve the research on crack depth in future studies.
We sincerely appreciate your time and effort in providing us with your insights. Should you have any further comments or suggestions, please feel free to share them with us.
Once again, thank you for your support and assistance in reviewing our manuscript.
Round 2
Reviewer 3 Report
Your answer #8.The bridge model is crucial for visualizing bridge damage and lays a solid foundation for establishing damage models. Section 4.3 describes the process of creating a cable-stayed bridge model in Revit and provides step-by-step instructions for creating various components. These instructions help readers understand the process and methods of creating these components and provide guidance on how to use Revit to create models. Although the content of this section may not be directly related to the main topic, establishing damage models is crucial. Therefore, Section 4.3 is of significant importance to the completeness and feasibility of this paper.
Q8. I do not contest the relevance but the quality of the presentation. The first sentence lacks a verb; at line 319 “main” is repeated. The overall effect of the paragraph is too oriented to a user manual with respect to point out the rationale of interesting passages. Moreover, the simple list of the operations as written is difficult to follow: try to switch to a pointed list or insert a flow chart.
Q12. Line 297. Sentence lacks a verb.
Author Response
Thank you very much for carefully reviewing our manuscript and providing valuable feedback.
We have made revisions to the sentence in the third paragraph of Section 4.2 and the overall structure and language in Section 4.3.
We hope that the revised manuscript meets your expectations. If you have any further comments or suggestions, please do not hesitate to let us know.
Author Response File: Author Response.pdf
