Controllable Spatial Filtering Method in Lensless Imaging

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Authors have demonstrated an ability of image reconstruction at different depths using multiple spatial filtering on diffraction image array. I have few concerns, including some naive, as following;  

 

1. Please explain clearly the novelty of work. As seen from the results, it looks like the current method is similar to the conventional one. Since only difference in the current method from conventional is increasing the number of spatial filtering by increasing the delta function integrating in the method section. 

2. it would be better if authors can show image of whole experimental system, as sample object image is shown seperately in fig 2(b). I am also curious to know, what is the width each object and seperation of objects. 

3. I am also wondering in fig 3; all plot may not be necessary, as they can be combined in one or two plots. Also, what are the spatial period and depth resolution. 

4. Separate discussion section may be added with more elaborate and quantitative comparison in conventional and current methods.

5. I would also appreciate if authors could think to do the spatial filtering in the experimental itself as a future direction. 

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

In the manuscript ‘Controllable spatial filtering method in lensless imaging’ Jang et al. present a method for reconstructing slice images at different depths from a diffraction image array (DIA) obtained through lensless diffraction grating imaging (DIA). The proposed method allows controllably extracting slice images at multiple depth planes by convolving the DIA with designed periodic delta function arrays matched to specific depth ranges.

Overall, this work introduces a new spatial filtering technique to enable the reconstruction of 3D scenes at multiple controllable depths from lens-less diffraction grating imaging data, presenting both theoretical derivations and experimental validation of the proposed method.

The manuscript is overall interesting and well-organised. However, I believe that some points should be addressed. Please consider the following comments:

1) The experimental setup (Section 4) utilizes a single wavelength (532 nm) for the laser source. Have you investigated the potential impact of using multiple wavelengths on the depth resolution and the performance of the controllable spatial filtering method?

2) In the Results section (Figure 5), you mention that the blurred noise increases in the proposed CEMD method, particularly when neighboring objects are close to the target object's depth. Could you provide more insights into strategies or techniques that could potentially mitigate this blur noise?

 

3) It would be beneficial to include a more detailed discussion on the practical limitations of the proposed method, such as the trade-off between depth resolution and spatial resolution, the impact of noise or aberrations on the reconstructed images, and any potential computational complexity considerations.

4) The manuscript could benefit from a more comprehensive comparison with other existing 3D imaging techniques, such as integral imaging or light field imaging, in terms of performance, complexity, and potential applications. Also, I would suggest the authors, to cite recent work on field manipulation in 3D imaging and scattering-assisted methodologies (e.g., Refs. [1-3]).

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References

[1] Stantchev, R.I., Mansfield, J.C., Edginton, R.S. et al. Subwavelength hyperspectral THz studies of articular cartilage. Sci Rep 8, 6924 (2018). https://doi.org/10.1038/s41598-018-25057-9

 

[2] V. Cecconi, et al., ACS Photonics 2024 11 (2), 362-368 DOI: 10.1021/acsphotonics.3c01671

[3] L. Olivieri, et.al., ACS Photonics 2023 10 (6), 1726-1734, DOI: 10.1021/acsphotonics.2c01727 

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

It looks like manuscript is now in a good shape after the revision. It may be accepted now.  

Reviewer 2 Report

Comments and Suggestions for Authors

Thanks to the authors for answering all my questions and clarifying some doubts about the manuscript. Having read the revised manuscript version, I thank the author for making the necessary amendments to improve text clarity, presentation quality, and referencing.