Error-reduction methods for shape measurement of low reflectivity specular surfaces by temporal phase unwrapping

Wu, Yue; Yue, Huimin; Zhao, Biyu; Ou, Zhonghua; Liu, Yong

doi:10.1364/acpc.2013.af2i.15

Cited by 1 publication

(1 citation statement)

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“…In [7], median filtering was used to preprocess captured images and filter out invalid data using a masking algorithm to improve the accuracy and precision of the phase solution. The wavelet-denoising method and the Savitzky-Golay method have been applied to suppress noise in captured images and improve the phase accuracy in [8,9] and [5], respectively. In [10], the captured images were converted into the frequency domain for filtering, thereby the influence of noise was suppressed and the phase accuracy was improved.…”

Section: Introductionmentioning

confidence: 99%

An iterative phase-correction method for low-quality phase-shift images and its application

Chen¹,

Jin²,

Zhang³

et al. 2021

Meas. Sci. Technol.

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To solve the issue of phase recovery from low-quality fringe images (where the low quality is caused by noise, non-linear intensity and surface reflectivity changes), an iterative phase-correction method is proposed. The high-phase-precision solution is achieved by regenerating the phase-shift-fringe images from the wrapped phase and performing iterative filtering. In general, compared with conventional methods, the proposed iterative phase-correction method has three main advantages: (a) it suppresses the influence of noise without interference from surface reflectivity; (b) it effectively improves the wrapped phase accuracy, thereby improving 3D measurement accuracy, and (c) it effectively recovers the absolute phase (determined by a multi-frequency heterodyne method) information of surfaces with very low or very high reflectivities, without the additional projection of phase-shift-fringe images. The effectiveness of the proposed iterative phase-correction method is verified by simulation and experiment. The proposed method, applied to binocularly structured light, can improve measurement accuracy and greatly improve the effectiveness of measurement of objects with drastic changes in reflectivity. Based on the calibration accuracy (without gamma calibration of the projector) described in this paper, the root-mean-square deviation of the measurement results for binocularly structured light can reach 0.0094 mm.

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Section: Introductionmentioning

confidence: 99%

An iterative phase-correction method for low-quality phase-shift images and its application

Chen¹,

Jin²,

Zhang³

et al. 2021

Meas. Sci. Technol.

View full text Add to dashboard Cite

show abstract

Error-reduction methods for shape measurement of low reflectivity specular surfaces by temporal phase unwrapping

Abstract: In phase measuring deflectometry, the measurement accuracy is relatively low with low reflectivity surface. Based on temporal phase unwrapping, two main noises are reduced to improve accuracy by least-square method and 3-frame method.

Cited by 1 publication

References 6 publications

An iterative phase-correction method for low-quality phase-shift images and its application

An iterative phase-correction method for low-quality phase-shift images and its application

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