Shape measurement by multi-illumination method in digital holographic interferometry

In this paper, temporal phase unwrapping and short time Fourier transform (STFT) are proposed for shape measurement of an object with height steps by digital holographic interferometry (DHI). A series of digital holograms is recorded with a high-speed CCD camera using a multi-illumination method. Each pixel is processed along the time axis independently of other pixels. Two novel methods are proposed to process the wrapped phase maps: the first method is based on complex phasor (CP) and temporal phase unwrapping, and the second method is based on CP and STFT. In the STFT method, continuous phase maps are obtained by integration of the exacted instantaneous frequency. The continuous phase map can characterize the profile of the object with height steps. An experiment is conducted to verify the validity of the proposed methods.

[1]  U. Schnars.  Direct phase determination in hologram interferometry with use of digitally recorded holograms , 1994 .

[2]  Werner P. O. Jueptner,et al.  Suppression of the dc term in digital holography , 1997 .

[3]  C. R. Coggrave,et al.  Optimization of shape measurement system based on spatial light modulators , 2000 .

[4]  J M Huntley,et al.  Temporal phase unwrapping: application to surface profiling of discontinuous objects. , 1997, Applied optics.

[5]  Mitsuo Takeda,et al.  Spatial-carrier fringe-pattern analysis and its applications to precision interferometry and profilometry: An overview , 1990 .

[6]  G. Sansoni,et al.  Three-dimensional imaging based on Gray-code light projection: characterization of the measuring algorithm and development of a measuring system for industrial applications. , 1997, Applied optics.

[7]  S. Mallat.  A wavelet tour of signal processing , 1998 .

[8]  Giancarlo Pedrini,et al.  Shape measurement of microscopic structures using digital holograms , 1999 .

[9]  C. Quan,et al.  Shape measurement using one frame projected sawtooth fringe pattern , 2005 .

[10]  I. Yamaguchi,et al.  Surface Shape Measurement by Phase-Shifting Digital Holography , 2001, Applied optics.

[11]  Yu Fu,et al.  Optical edge projection for surface contouring , 2005 .

[12]  M. Takeda,et al.  Fourier-transform speckle profilometry: three-dimensional shape measurements of diffuse objects with large height steps and/or spatially isolated surfaces. , 1994, Applied optics.

[13]  Hao Chen,et al.  Temporal phase retrieval from a complex field in digital holographic interferometry. , 2007, Optics letters.

[14]  N Abramson.  Holographic contouring by translation. , 1976, Applied optics.

[15]  Wolfgang Osten,et al.  Direct shape measurement by digital wavefront reconstruction and multi-wavelength contouring , 2000 .

[16]  T. Kreis.  Handbook of Holographic Interferometry: Optical and Digital Methods , 2004 .

[17]  V. Srinivasan,et al.  Automated phase-measuring profilometry of 3-D diffuse objects. , 1984, Applied optics.

[18]  J S Zelenka,et al.  Multiple-index holographic contouring. , 1969, Applied optics.

[19]  D. Meadows,et al.  Generation of surface contours by moiré patterns. , 1970, Applied optics.

[20]  Chenggen Quan,et al.  Shape measurement of small objects using LCD fringe projection with phase shifting , 2001 .

[21]  Dennis C. Ghiglia,et al.  Two-Dimensional Phase Unwrapping: Theory, Algorithms, and Software , 1998 .

[22]  Manuel Servin,et al.  Profilometry for the measurement of 3-D object shapes based on regularized filters , 1999 .

[23]  W. Osten,et al.  Digital recording and numerical reconstruction of lensless fourier holograms in optical metrology. , 1999, Applied optics.

[24]  U. Schnars,et al.  Digital Holography: Digital Hologram Recording, Numerical Reconstruction, and Related Techniques , 2004 .

[25]  Fu-Pen Chiang,et al.  Color-encoded digital fringe projection technique for high-speed three-dimensional surface contouring , 1999 .

[26]  B Ströbel,et al.  Processing of interferometric phase maps as complex-valued phasor images. , 1996, Applied optics.

[27]  Yu Fu,et al.  Profiling of objects with height steps by wavelet analysis of shadow moiré fringes. , 2005, Applied optics.

[28]  A A Friesem,et al.  Fringe formation in two-wavelength contour holography. , 1976, Applied optics.

[29]  J. M. Huntley,et al.  Temporal phase-unwrapping algorithm for automated interferogram analysis. , 1993, Applied optics.

[30]  Xianyu Su,et al.  Automated phase-measuring profilometry using defocused projection of a Ronchi grating , 1992 .

[31]  Orhan Arikan,et al.  Short-time Fourier transform: two fundamental properties and an optimal implementation , 2003, IEEE Trans. Signal Process..

[32]  Yu Fu,et al.  Determination of surface contour by temporal analysis of shadow moiré fringes , 2004 .

[33]  J. Fujimoto,et al.  Determination of the vibrating phase by a time-averaged shadow moire method. , 1982, Applied optics.

[34]  M. Takeda,et al.  Fourier transform profilometry for the automatic measurement of 3-D object shapes. , 1983, Applied optics.