Depth Measurement Error Analysis and Structural Parameter Correction of Structured Light Depth Imager

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This manuscript proposed an innovative method for correcting structural parameters of structured light depth imagers to reduce fringe inference measurement error. It is meaningful for the field of 3D metrology. I have seen its prospects in online defect inspection and machining. I am writing to enquire about the details:

1.     Did you estimate Error model? Such as linear model regressive analysis

2.     In your experiments, was the etalon used to obtain the length error?

Author Response

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Reviewer 2 Report

Comments and Suggestions for Authors

Aiming at the errors of parameters of structured light system, the authors proposed an innovative method for correcting structural parameters to reduce the depth measurement error caused by structural parameter errors. The research is meaningful for improving the 3D measurement accuracy of structured light system. I recommend that this paper could be accepted to be published after minor revised. Some detail comments are as follow:

 1. The parameters of structured light system are obtained by calibration. And the error of the parameter varies with the position in 3D space. Does the model in the paper take this situation into account?

2. I suggest that the more experimental data should be added. For example, the measurement results of standard ball, metrological standard ballbar or gauge block could be more proper to prove the efficiency of the proposed model in the paper.

Comments on the Quality of English Language

Good.

Author Response

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Reviewer 3 Report

Comments and Suggestions for Authors

In this very technical paper, the authors present a protocol to adjust the three structural parameters involved in structured-light depth imaging in order to improve the accuracy of the results. They succeed in improving the accuracy on the location of a reference plane from the millimeter range up to the tens micrometer scale. This appears as a very incremental work in the field : one should ask why these parameters are not correctly adjusted in the first place ? And in fact this raises another fundamental question :  the authors performed their adjustment on only one reference plane but, as they wrote in their introduction, « the world is three dimensional »… In order to validate the relevance of such an adjustment, the accuracy improvement has to be checked on other planes (at different distances and orientations) after the modification of the parameters. In other words, there is no proof that the observed improvement does not deteriorate the performances for other planes and geometries. The authors present a result at the end (figure 8) obtained with their method, but not with the previous one, so that no comparison can be performed. Furthermore, this is a qualitative result, and qualitative results seem useless when the discussed accuracy is in the millimeter or sub-millimeter range. I have also a problem with formula (9), where y’_0 do not appear in the right member. For all these reasons, I think that this paper cannot be published in the present form.

Author Response

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Round 2

Reviewer 3 Report

Comments and Suggestions for Authors

The authors made significantly changes in their manuscript, which mostly answer to all my remarks. I therefore feel that it could be published in the present form.