A Polarized Structured Light Method for the 3D Measurement of High-Reflective Surfaces

Round 1

Reviewer 1 Report

This paper proposes a technique for 3D reconstruction, which is a Gray code technique based on polarized system. The technology uses polarized SL method to address the reconstruction issues on high reflectance surfaces. The inherent limitation of SL method is to recover the surface information of the high light region. The polarization system and image fusion method are proposed based on the interval optimal projection intensity, which can achieve excellent reconstruction outcomes on highly reflective surfaces.

Currently, structured light topography measurement technology mostly uses phase shift technique, which works on the images acquired by multiple projections. The proposed method is capable of fast, complete, and high-precision reconstruction of highly reflective surfaces with a single exposure, which is the innovation of this technology. This project provides a new measurement method, which has been experimentally proven to be concise, clear, and effective. I recommend that this article can be accepted by Photonics. The following are some suggestions.

1. Regarding the procedure of the proposed method, the authors should provide a detailed flow chart to facilitate readers' implement this method.

2. In the article, the authors should analyze the possible problems with this measure and provide corresponding solutions.

3. This article can improve the speed of 3D reconstruction, but the experimental results do not show the value of measurement time of the proposed method.

I think the article can be improved by considering the comment.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 2 Report

In the article titled "A Polarized Structured Light Method for the 3D Measurement of High-Reflective Surfaces," the authors outline a pipeline for reconstructing 3D surface imaging of samples with highly reflective areas using a polarization camera. This pipeline comprises fringe image registration, weight-map generation, point cloud fusion, and smoothing. The authors experimentally compare their method with the multi-exposure method, demonstrating that the former outperforms the latter by reconstructing complete images without missing pixels. This work provides a valuable complement to current high dynamic range imaging methods. However, several issues need to be addressed before the article is suitable for publication:

1) The reconstruction process demonstration could be enhanced. Although Figure 1 includes an inset displaying a weight map and Section 3.2 provides a description, it remains unclear how the fusion method addresses low SNR regions and fills in missing parts in specific examples. The authors should consider presenting figures illustrating weight map generation and image complementation to clarify the process.

2) Reconstruction errors have not been quantified. How is the error distributed? Moreover, how does the error of the proposed method compare to that of the multi-exposure method?

3) What distinguishes this work from other polarization-based methods? The authors review some related work, but a direct comparison between the proposed method and others is lacking.

4) What is the fusion algorithm of the multi-exposure reference in Figure 13? Is it possible to apply the proposed fusion algorithm to other hardware modalities of HDR imaging?

5) The authors assert that multi-exposure/multi-view methods are more time-consuming than polarization. However, polarization methods rely on spatial multiplexity and sacrifice SNR due to pixelated polarizers, resulting in lower total signal strength at a fixed acquisition time [1]. Please comment on this point. Given the relatively universal nature of the entire processing pipeline, under what circumstances should one opt for polarization over other methods, such as multi-exposure?

[1] Feng, Shijie, et al. "High dynamic range 3D measurements with fringe projection profilometry: a review." Measurement Science and Technology 29.12 (2018): 122001.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

The authors have satisfactorily addressed my concerns. I recommend the publication of the manuscript in its current form.