Three Dimensional Measurements by Deflectometry and Double Hilbert Transform

TL;DR

This paper introduces an improved phase retrieval method using double Hilbert transform for fast, automated 3D measurements in deflectometry, effectively suppressing background noise with only one image.

Contribution

It presents a novel double Hilbert transform technique that simplifies phase measurement and noise suppression in deflectometry, requiring only a single image for accurate 3D surface profiling.

Findings

Effective background noise suppression demonstrated

Single-image phase retrieval achieved

Method validated through simulation and experiments

Abstract

An improved phase retrieval method based Hilbert transform is introduced to quantitatively calculate the phase distribution from distorted fringe pattern. Also phase measurement deflectomety are widely used in specular type samples. The background noise or bias should be suppressed prior to apply Hilbert transform. A method for suppression background noise double Hilbert transform is presented, which requires only one image. The method is easy to implement, and it is able to conducting automated fast measurements. We have demonstrated the double Hilbert transform method to retrieve the phase and background suppression by computer simulation and experiment in phase measuring deflectometry method.