A Feasibility Study for a Hand-Held Acoustic Imaging Camera
Round 1
Reviewer 1 Report
This article proposes a new dual cam for acoustic imaging with localization, which is relatively new from an application perspective. However, the article is not like a research paper, but more like a technical report. There is no in-depth theoretical explanation or improvement methods for the key technologies. Therefore, it is not suitable for publication.
Comments are detailed as following:
1. What's the difference between the new POC and the current POC? Only using multi-channel USB connection cannot support the key novelty of the paper. In section 2, there is no system structure plot for the new POC device. Then the author doesn't know any details of the system, and cannot make sure it is novel.
2. The physical size reduction needs re-design of the beamforming algorithm. But how? There is no technical details about the improved signal processing methods. How to make the down-sized device to have a similar performance with the current POC? The authors need to make a in-depth theoretical explanation.
In Section 2.1 it needs to give out the theoritical explanation for the key improved beamforming algorithm which can remain the performance when the device is down-sized. While the simuliation method can be put into the result part.
3. It mentioned that in the new POC, only the upper harmonics of the audio signals, neglecting the fundamental frequency components are used. But what is the differrence when compared to the results with both? There is no comparison to convince how it works well.
4. References are too old. Only works before 2015 are mentioned. How about the development of acoustic imaging in recent few years？
5. If a figure contains multiple sub-graphs, it is suggested to name them (a) ,（b）, (c) and etc, which are convenient for figure citing to make some explanations.
Author Response
Report #1
Thank you for sharing your feedback. I appreciate you entrusting me to provide suggestions to strengthen my work.
1) First of all, according to your revision, I rewrote most of the paper to achieve a more scientific and clear approach as requested from a scientific paper in a journal.
In Section 4 I explained the novelty of the approach described for the audio simulation and hardware implementation.
Moreover, in my feasibility study, I have clarified the parameters of the entire simulation in paragraph #7.
2-3) In my feasibility study, the downsize guarantees better performance by optimizing the FOV (field of view) and the frequency bandwidth according to the array size reduction, to explore upper harmonic reconstruction to determine if intelligibility is retained without fundamental frequencies, comparing results using the full audio spectrum versus upper harmonics only.
4) I enlarged and updated the bibliography with more recent literature.
5) I reformatted all the figures and captions of the paper referring to them as such would make the discussion clearer when citing them in the article.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
I send you my suggestions, which I consider helpful to strengthen your paper
It is necessary to extend the caption of Figure 1, for a clear understanding.
I consider that the author must add a figure that describes the variables associated with angle θ (and θ0) and φ (and φ0), y, and x used in the equation (1).
d=0,25 m ???, then, how many microphones exist in the array?
In general, the author must increase the size of the text label (axes title) in figures.
The author must use the same format for all references, including DOI.
It is important that the author includes in the conclusions something about the physical results.
Comments for author File: Comments.pdf
Author Response
Report #2
Thank you for sharing your feedback. I appreciate you entrusting me to provide suggestions to strengthen my work.
Regarding Figure 1, I agree that expanding the caption would help the reader's understanding.
I preferred to use Figures 2 and 4 in the new version to better explain the underlying concept.
Adding an additional figure to illustrate the key variables in Equation 1 is a good recommendation.
In fact, I added Figure 10 and rewrote most of the paper to achieve a more scientific and clear approach.
The question about the number of microphones in the array, given the 0.25 m aperture, highlights an ambiguity in the current draft.
Therefore, I have clarified the parameters of the entire simulation in the new paragraph #7.
Increasing the size of the text labels in the figures is a good suggestion to improve readability.
I have therefore modified all the figures following your suggestions.
Using a reference format consistent with DOIs, when available, would improve scientific rigour.
Therefore, I added DOIs by reformatting the entire bibliography accordingly.
Finally, I have included an additional discussion of the physical implications of the results in the Conclusion section.
Author Response File: Author Response.pdf
Reviewer 3 Report
The author presents the continuation of his research on an Acoustic Imaging sensor, with the paper focusing on the overall presentation of the POC device, including its advantages over the initial prototype, simulation and even a business/industry overview. The device is a multi-input cam with an array of microphones, with beamforming being employed to synthesize a 2D Acoustic Image.
Although the device is very interesting and the efforts of the author are commendable, the overall presentation of the paper lacks in clarity and organization.
The Introduction should be re-organized as follows:
- a general presentation of the problem (acoustic imaging and current solutions) must be given
- the technical basis of the proposed solution (e.g., beamforming) has to be better introduced and clearly explained
- the reasoning behind the proposal have to be clear as well as its basic technology. As an example, "the 128 inputs" are mentioned without explaining what they are and where do they come from. Please, re-arrange the whole Introduction.
- a short summary about the focus of the paper and of the research must be given.
Moreover, some references to Figures are off: Figure 1 is referenced in the Material and Methods, but it's unclear why.
Most technical details need more explanation, including beamforming, the reasoning behind the considerations on Deep Learning, the meaning of a "lobe" and in general the physical model used, the term "grated lobes".
Figure 25 is useless, please remove to enhance readability.
In general, a more professional writing style is strongly suggested, as well as a more organized structure within the paper, and more information behind any technical choice or mention.
The quality of the scientific overview is good, and the paper is interesting, but it needs to be re-organized for readability and clarity before publication.
The English of the paper needs to be revised. Many sentences are clearly a literal translitteration from another language (Italian?), which results into obsolete or unfitting words (such as "opportune") or sentence constructions.
Overall, the writing style is a bit too colloquial and not professional enough for a scientific paper, and needs to be addressed accordingly.
Author Response
Report #3
Thank you for the opportunity to review my manuscript and share your feedback.
I appreciate you entrusting me to provide suggestions to strengthen my work.
I agree the Introduction requires reorganization to present the background, motivation, and focus of the research more clearly.
I expanded the general problem before introducing the proposed approach. According to your revision, I rewrote and re-organized most of the paper to achieve a more scientific and clear approach as requested, adopting a more formal tone appropriate for a scientific publication throughout.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
This work actually focuses on the key theory explanation and simulation evaluation for the technical feasibilty of a miniaturized Acoustic Imaging Camera. The original and incremental work is very few. The reviewer still worries about its real feasibility. For a miniaturized Acoustic Imaging Camera, most techniques are mature. The key point is how to miniturize it further to get an optimal design. Yes, the author talked about some related to the technical limitation and the tradeoff of the design consideration. And use some simulation work to support the conclusion. However, the aim of the paper is to provide a feasible method for a miniaturized Acoustic Imaging Camera. The real implementation of the camera is also the key work in this paper to support its theory and simulation results. Thus the reviewer suggests that real experimental results should be supplemented to prove its feasibility. And let's see the difference of the results with/without the optimization method for the sensor array layout, which is quite important for this paper, but also for the peer researchers in this field. Then the reviewer still thinks the contribution of this paper is subtle to be published in this journal.
English language is fine but it can be checked again to avoid grammar errors.
Author Response
Dear Reviewer, the article presents an idea and the feasibility study related to it, while the realisation of a prototype to experimentally measure the results is postponed to a later work and is supported by this feasibility study. There are, however, simulation results that, compared to the results obtained on the first working and tested prototype, provide a comparison on the goodness of the idea of resizing the microphone array to make it compatible and interfaceable with widely used hardware for commercial interests of market penetration and not only for issues of practicality and ease of use. My intention is to integrate the experimental results in a future publication after the hardware implementation of the prototype that the feasibility study indicated as possible. Kind regards.
