Development of a high-precision surface metrology system using structured light projection

Abstract In this paper, we present a high-precision surface metrology system based on structured light projection. Gray code patterns are projected onto the object surface by a DMD projection device and a CCD camera captures the distorted pattern images. For the purpose of precision measurement, a 3D mathematical model is proposed for the system and a calibration process is developed to obtain system parameters. The pattern is encoded with a unique ID and correspondence pairs between the CCD and DMD can be found. The surface profile can be computed by the calibrated model. In order to acquire higher measurement resolution, we propose a correspondence matching method which combines Gray codes encoding and sub-pixel edge detection. With a line-shifting procedure, the measurement resolution is elevated four times higher. Experiment results demonstrate the system has measurement area of 12 × 9 mm 2 , with lateral resolution about 10 μm and vertical resolution about 3 μm.

[1]  Cunwei Lu,et al.  An absolute depth range measurement of 3-D objects based on modulation Moire topography , 2000, Proceedings 15th International Conference on Pattern Recognition. ICPR-2000.

[2]  Giovanna Sansoni,et al.  Calibration and performance evaluation of a 3-D imaging sensor based on the projection of structured light , 2000, IEEE Trans. Instrum. Meas..

[3]  Katherine Creath,et al.  Choosing a phase-measurement algorithm for measurement of coated LIGO optics , 2000, SPIE Optics + Photonics.

[4]  Robert B. Fisher,et al.  A Comparison of Algorithms for Subpixel Peak Detection , 1996 .

[5]  Sara Lazzari,et al.  3D imager for dimensional gauging of industrial workpieces: state of the art of the development of a robust and versatile system , 1997, Proceedings. International Conference on Recent Advances in 3-D Digital Imaging and Modeling (Cat. No.97TB100134).

[6]  William H. Press,et al.  Numerical recipes in C , 2002 .

[7]  U. Minoni,et al.  A novel, adaptive system for 3-D optical profilometry using a liquid crystal light projector , 1994 .

[8]  Richard Szeliski,et al.  High-accuracy stereo depth maps using structured light , 2003, 2003 IEEE Computer Society Conference on Computer Vision and Pattern Recognition, 2003. Proceedings..

[9]  Roger Y. Tsai,et al.  A versatile camera calibration technique for high-accuracy 3D machine vision metrology using off-the-shelf TV cameras and lenses , 1987, IEEE J. Robotics Autom..

[10]  Xianyu Su,et al.  Phase unwrapping algorithm based on fringe frequency analysis in Fourier-transform profilometry , 2001 .

[11]  G. Sensoni.  3D optical whole-field range sensor: development of procedures for the automatic set-up of the measurement and the calibration of the system , 1999, IMTC/99. Proceedings of the 16th IEEE Instrumentation and Measurement Technology Conference (Cat. No.99CH36309).

[12]  Kiyoshi Takamasu,et al.  3D profile measurement by color pattern projection and system calibration , 2002, 2002 IEEE International Conference on Industrial Technology, 2002. IEEE ICIT '02..

[13]  Jens Guehring,et al.  Dense 3D surface acquisition by structured light using off-the-shelf components , 2000, IS&T/SPIE Electronic Imaging.

[14]  Mumin Song,et al.  Overview of three-dimensional shape measurement using optical methods , 2000 .

[15]  Gottfried Frankowski,et al.  Real-time 3D shape measurement with digital stripe projection by Texas Instruments Micro Mirror Devices DMD , 2000, Electronic Imaging.

[16]  Youfu Li,et al.  Self-recalibration of a colour-encoded light system for automated three-dimensional measurements , 2003 .

[17]  Chia-Hsiang Menq,et al.  Automatic camera calibration for a multiple-sensor integrated coordinate measurement system , 2001, IEEE Trans. Robotics Autom..

[18]  David R Burton,et al.  Technique for phase measurement and surface reconstruction by use of colored structured light. , 2002, Applied optics.

[19]  Motoharu Fujigaki,et al.  Accuracy of Real-Time Shape Measurement by Phase-Shifting Grid Method Using Correlation , 2000 .

[20]  David R. Burton,et al.  The use of carrier frequency shifting for the elimination of phase discontinuities in Fourier transform profilometry , 1995 .

[21]  Guowen Lu,et al.  Absolute measurement of surface profiles with phase-shifting projected fringe profilometry , 1999, Optics + Photonics.

[22]  Alan M. McIvor,et al.  Accurate 3D measurement using a structured light system , 1998, Image Vis. Comput..

[23]  Dieter Fritsch,et al.  DATA PROCESSING AND CALIBRATION OF A CROSS-PATTERN STRIPE PROJECTOR , 2000 .

[24]  H Zhao,et al.  Phase-unwrapping algorithm for the measurement of three-dimensional object shapes. , 1994, Applied optics.