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Proceedings ArticleDOI

RGB speckle pattern interferometry for surface metrology

TL;DR: In this article, multi-wavelength speckle pattern interferometry using a Bayer RGB sensor is discussed, where the colour images acquired using RGB sensor are split in to its individual components and corresponding interference phase map is recovered using error compensating phase shifting algorithm.
Abstract: Digital speckle pattern interferometry (DSPI) has been widely used for surface metrology of optically rough surfaces. Single visible wavelength can provide high measurement accuracy, but it limits the deformation measurement range of the interferometer. Also, it is difficult to reveal the shape of a rough surface with one wavelength in normal illumination and observation geometry. Using more than one visible wavelength in DSPI, one can measure large deformations as well as shape using synthetic wavelength approach. In this work, we will discuss multi-wavelength speckle pattern interferometry using a Bayer RGB sensor. The colour sensor allows simultaneous acquisition of speckle patterns at different wavelengths. The colour images acquired using RGB sensor is split in to its individual components and corresponding interference phase map is recovered using error compensating phase shifting algorithm. The wrapped phase is unwrapped to quantify the deformation or shape information of the sample under inspection. Theoretical background of RGB interferometry for deformation and shape measurements, and experimental results will be presented.

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Book ChapterDOI

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01 Jan 2012

139,059 citations


"RGB speckle pattern interferometry ..." refers methods in this paper

  • ...The interferometric methods used to overcome such problems are: 2λ-phase shifting interferometry (2λ-PSI) [15-17], scanning white light interferometry (SWI)[18-20], spectrally resolved white light interferometry (SR-WLI) [21, 22], white light phase shifting interferometry[23-25], and 3λ-phase shifting interferometry (3λ-PSI) [26-28]....

    [...]

01 Jan 2015

12,972 citations


"RGB speckle pattern interferometry ..." refers methods in this paper

  • ...The interferometric methods used to overcome such problems are: 2λ-phase shifting interferometry (2λ-PSI) [15-17], scanning white light interferometry (SWI)[18-20], spectrally resolved white light interferometry (SR-WLI) [21, 22], white light phase shifting interferometry[23-25], and 3λ-phase shifting interferometry (3λ-PSI) [26-28]....

    [...]

Journal ArticleDOI
TL;DR: The new 5-frame algorithm and two new 6-frame algorithms have smaller phase errors caused by phase-shifter miscalibration than any of the common 3-, 4- or 5- frame algorithms.
Abstract: Phase-shifting interferometry suffers from two main sources of error: phase-shift miscalibration and detector nonlinearity. Algorithms that calculate the phase of a measured wave front require a high degree of tolerance for these error sources. An extended method for deriving such error-compensating algorithms patterned on the sequential application of the averaging technique is proposed here. Two classes of algorithms were derived. One class is based on the popular three-frame technique, and the other class is based on the 4-frame technique. The derivation of algorithms in these classes was calculated for algorithms with up to six frames. The new 5-frame algorithm and two new 6-frame algorithms have smaller phase errors caused by phase-shifter miscalibration than any of the common 3-, 4- or 5-frame algorithms. An analysis of the errors resulting from algorithms in both classes is provided by computer simulation and by an investigation of the spectra of sampling functions.

383 citations

01 Dec 2000

315 citations


"RGB speckle pattern interferometry ..." refers background in this paper

  • ...Digital speckle pattern interferometry (DPSI) or TV holography (TVH) based on single wavelength configuration offers excellent resolution and high sensitivity for optical metrology applications [1-6]....

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Journal ArticleDOI
TL;DR: By introducing the phase data of a third wavelength, one can measure the phase of a very steep wave front and the repeatability of the measurement is better than 25-A rms (λ = 6328 A).
Abstract: This paper describes a method to enhance the capability of two-wavelength phase-shifting interferometry. By introducing the phase data of a third wavelength, one can measure the phase of a very steep wave front. Experiments have been performed using a linear detector array to measure surface height of an off-axis parabola. For the wave front being measured the optical path difference between adjacent detector pixels was as large as 3.3 waves. After temporal averaging of five sets of data, the repeatability of the measurement is better than 25-A rms (λ = 6328 A).

309 citations