UBathy (v2.0): A Software to Obtain the Bathymetry from Video Imagery
Round 1
Reviewer 1 Report
Dear authors, I read through your manuscript with interest. Since it describes a workflow that is an extension of what had previously been published, it is easy for me, as reviewer, to agree with the fundamental soundness of your work. The results are also convincing. In addition to the minor editorial suggestions in the attached pdf file, I have only comments, none of which you need necessarily address prior to publication.
1) To assess the value of the additions created for your version 2.0, it would have been ideal to compare your results to those obtained with version 1. You have done similar comparisons, which are meaningful, but not this one. Even better would have been to compare results to those obtainable to competing algorithms, though I imagine this is very difficult to do in practice.
2) As someone who works on SDB, but not with wave inversion, I am keen to explore the limitations of the wave-based approach. I know you have not done that here, showing results only from a single very suitable field site, but I think it would be valuable, in your discussion, to write about the kinds of environments in which your method is likely to work well, and also those where it will likely not work so well.
3) Lastly, what is next for wave-based SDB? Have you reached the end of what is possibly to achieve with this approach? Could it be improved? I would like to read a bit about that, especially in relation to planned video-camera space missions.
Comments for author File: 
Comments.pdf
Author Response
pdf attached
Author Response File: Author Response.pdf
Reviewer 2 Report
This manuscript presents an open-source software for obtaining nearshore water depth from video imagery. It is a fascinating and meaningful work, and the manuscript is well-written. However, several concerns need to be addressed before the manuscript can be considered for publication.
Line44-Line83: the review of existing schemes is too much and needs to be simplified. I would suggest comparing the advantages & disadvantages of the three algorithms, pointing out the current issues, and then clarifying the necessity of proposing UBathy (v2.0), based on Figure 1.
Line131: in general, "mean sea level" refers specifically to an idealized vertical datum that is considered fixed over a period of time. Herein, "mean water level" or "tidal level" may be more appropriate.
Please check the manuscript's equations, symbols, and corresponding interpretations carefully. For example, "zs" should be interpreted as "the surface elevation" (Line236); "wavelength" should be revised as "wavenumber" (Line243).
In Section 3. To reflect the progress of UBathy (v2.0), is it advisable to compare it with the algorithms mentioned in the Introduction based on the same dataset?
Line456-Line457: "as the filtering period is increased, the better the results are." This seems incorrect based on the results in the "videos of 160s" column in Table 4.
In Figures 12-14, there should be clear labels to make it easier for the readers to make the distinction.
Last but not least, many abbreviations have been used in this manuscript. Please double-check and standardize the format of all abbreviations. 1) Abbreviations should be marked when a word first appears, and it is sufficient to use the abbreviation directly in the following. For example, line47: "Empirical Orthogonal Functions (EOF)". 2) Using an abbreviation directly when a word first appears is not advisable. For example, line75: "2D-FFT" should be modified to "2-Dimensional Fast Fourier Transform (2D-FFT)". 3) E.g., "Dynamic Mode Decomposition [DMD, 18]" should be modified to "Dynamic Mode Decomposition (DMD) [18]" (line72).
Author Response
pdf attached
Author Response File: Author Response.pdf
