Please use this identifier to cite or link to this item:
Title: Profiling of objects with height steps by wavelet analysis of shadow moiré fringes
Authors: Quan, Chenggen
Fu, Yu
Tay, Cho Jui
Tan, Jia Min
Keywords: DRNTU::Science::Physics::Optics and light
Issue Date: 2005
Source: Quan, C., Fu, Y., Tay, C. J., & Tan, J. M. (2005). Profiling of objects with height steps by wavelet analysis of shadow moiré fringes. Applied Optics, 44(16), 3284-3290.
Series/Report no.: Applied Optics
Abstract: A temporal wavelet analysis algorithm is proposed for shadow-moiré-based three-dimensional surface profiling on objects having discontinuous height steps. A grating is positioned close to an object, and its shadow is observed through the grating. The moiré fringe patterns vary when the grating is in-plane rotating. A series of fringe patterns are captured by a CCD camera at different rotating angles. Phase values are evaluated point by point with the continuous wavelet transform. From the phase values of each point on the object, the distance between the object and the grating can be retrieved. The surface profile is obtained without temporal or spatial phase unwrapping. This technique is applicable to objects with discontinuous height steps, which are impossible to measure with conventional shadow moiré topography. Two specimens are tested to demonstrate the validity of the method: One is an object with a height step of 1.6 mm, and another is a small coin with unevenness of less than 0.2 mm. The experimental results are compared with test results by use of the mechanical stylus method.
ISSN: 0003-6935
DOI: 10.1364/AO.44.003284
Rights: This paper was published in [Applied Optics] and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: []. Systematic or multiple reproduction or distribution to multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law.
Fulltext Permission: open
Fulltext Availability: With Fulltext
Appears in Collections:TL Journal Articles

Files in This Item:
File Description SizeFormat 
Profiling of objects with height steps by wavelet analysis of shadow moiré fringes.pdf1.94 MBAdobe PDFThumbnail

Google ScholarTM




Items in DR-NTU are protected by copyright, with all rights reserved, unless otherwise indicated.