LED-based multi-wavelength phase imaging interference microscopy

Warnasooriya, Nilanthi; Kim, M K

doi:10.1364/oe.15.009239

Cited by 78 publications

(47 citation statements)

References 13 publications

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“…Especially when a multiplewavelength technique is utilized, the measurement can be performed point by point without any spatial phase unwrapping; therefore, the step-height is not a problem at all. Over the years, extensive research has been conducted on two-or multiple-wavelength phase-shifting techniques [1][2][3][4][5][6][7][8][9][10][11][12][13][14] and temporal phase unwrapping. 15,16 All these efforts were intending to measure the step-height object or alleviate the limitations of phase unwrapping.…”

Section: Introductionmentioning

confidence: 99%

Phase unwrapping error reduction framework for a multiple-wavelength phase-shifting algorithm

Zhang

2009

Opt. Eng

109

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We address a framework to reduce the unwrapping errors of the measurement system using a digital multiplewavelength phase-shifting algorithm. In particular, the following framework is proposed: (1) smooth the raw phase by smoothing the sine and cosine images of the phase computation of the inverse tangent function; (2) locate and remove the incorrectly unwrapped points by the monotonicity condition of the phase map; (3) obtain the unwrapped phase map for the shortest wavelength without smoothing; (4) detect holes and fill them to preserve as much useful information as possible. Experiments demonstrated that the proposed framework significantly alleviated the measurement errors caused by the phase noise. KeywordsVirtual Reality Applications Center, Human Computer Interaction, structured light, phase shifting, phase unwrapping, multiple wavelength, phase error RightsCopyright 2009 Society of Photo-Optical Instrumentation Engineers. One print or electronic copy may be made for personal use only. Systematic electronic or print reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited. Abstract. We address a framework to reduce the unwrapping errors of the measurement system using a digital multiple-wavelength phaseshifting algorithm. In particular, the following framework is proposed: ͑1͒ smooth the raw phase by smoothing the sine and cosine images of the phase computation of the inverse tangent function; ͑2͒ locate and remove the incorrectly unwrapped points by the monotonicity condition of the phase map; ͑3͒ obtain the unwrapped phase map for the shortest wavelength without smoothing; ͑4͒ detect holes and fill them to preserve as much useful information as possible. Experiments demonstrated that the proposed framework significantly alleviated the measurement errors caused by the phase noise.

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Section: Introductionmentioning

confidence: 99%

Phase unwrapping error reduction framework for a multiple-wavelength phase-shifting algorithm

Zhang

2009

Opt. Eng

109

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“…They were used widely to measure larger step height. [8][9][10][11] Huntley et al proposed a technique called temporal phase unwrapping algorithm 12 and apply it to measure discontinuous objects. 13 The fundamental concept of this technique is that the phase is unwrapped in time axis rather than in x − y plane spatially.…”

Section: Introductionmentioning

confidence: 99%

Digital multiple wavelength phase shifting algorithm

Zhang

2009

SPIE Proceedings

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This paper presents a digital multiple-wavelength phase-shifting technique for three-dimensional shape measurement. The projected phase-shifted fringe images have wavelengths of λ κ = W/2 κ-1 (k = 1,2,3...). The phase unwrapping is not needed for the longest wavelength because a single fringe covers the whole area. The shorter wavelength phase, φκ(x,y), is unwrapped by referring to the previously unwrapped longer wavelength phase, Φ k-1 (x,y), pixel by pixel without accessing its neighborhood pixels. Experiments demonstrate that this technique has low noise and less sensitivity to motion. It can be used to measure arbitrary step height and multiple objects simultaneously. 1, 2, 3...). The phase unwrapping is not needed for the longest wavelength because a single fringe covers the whole area. The shorter wavelength phase, φ k (x, y), is unwrapped by referring to the previously unwrapped longer wavelength phase, Φ k−1 (x, y), pixel by pixel without accessing its neighborhood pixels. Experiments demonstrate that this technique has low noise and less sensitivity to motion. It can be used to measure arbitrary step height and multiple objects simultaneously.

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“…In DH, it is a simple matter to compensate for the aberration by adjustment of the reconstruction distance [151] or by subtracting reference holograms without the object [51]. The OPU was also applied to phase-shifting interference microscopy using three LEDs as light sources [152,153]. The method is fast enough for real-time vibration analysis [70].…”

Section: Optical Phase Unwrappingmentioning

confidence: 99%

Principles and techniques of digital holographic microscopy

2010

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Abstract. Digital holography is an emerging field of new paradigm in general imaging applications. We present a review of a subset of the research and development activities in digital holography, with emphasis on microscopy techniques and applications. First, the basic results from the general theory of holography, based on the scalar diffraction theory, are summarized, and a general description of the digital holographic microscopy process is given, including quantitative phase microscopy. Several numerical diffraction methods are described and compared, and a number of representative configurations used in digital holography are described, including off-axis Fresnel, Fourier, image plane, in-line, Gabor, and phase-shifting digital holographies. Then we survey numerical techniques that give rise to unique capabilities of digital holography, including suppression of dc and twin image terms, pixel resolution control, optical phase unwrapping, aberration compensation, and others. A survey is also given of representative application areas, including biomedical microscopy, particle field holography, micrometrology, and holographic tomography, as well as some of the special techniques, such as holography of total internal reflection, optical scanning holography, digital interference holography, and heterodyne holography. The review is intended for students and new researchers interested in developing new techniques and exploring new applications of digital holography. C 2010 Society of Photo-Optical Instrumentation Engineers.

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LED-based multi-wavelength phase imaging interference microscopy

Cited by 78 publications

References 13 publications

Phase unwrapping error reduction framework for a multiple-wavelength phase-shifting algorithm

Phase unwrapping error reduction framework for a multiple-wavelength phase-shifting algorithm

Digital multiple wavelength phase shifting algorithm

Principles and techniques of digital holographic microscopy

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