Phase error correction by π -shift odd-step fringe projection and speckle filtering in phase measuring profilometry

Phase measuring profilometry based on structured illumination with a digital projector has great flexibility. However, the phase error introduced by the gamma nonlinearity of the projector and the presence of speckle noise inevitably decreases the accuracy and resolution of the measurement. This pap...

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Bibliographic Details
Published in:Optical engineering 2010-04, Vol.49 (4), p.43603
Main Author: Wu, Shuangqing
Format: Article
Language:English
Subjects:
Algorithms
Filtering
Flexibility
Noise
Phase error
Projection
Projectors
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Summary:Phase measuring profilometry based on structured illumination with a digital projector has great flexibility. However, the phase error introduced by the gamma nonlinearity of the projector and the presence of speckle noise inevitably decreases the accuracy and resolution of the measurement. This paper presents a new phase error correction algorithm by which the odd-step fringe projection is done twice with an initial phase shift of pi between, and the two captured deformed fringe images are then digitally subtracted. The speckle noise is further suppressed by applying a sine-cosine median filter. Both theoretical analysis and experimental results showed that this algorithm is effective and fast.
ISSN:0091-3286
DOI:10.1117/1.3407430