Phase-Crossing Algorithm for White-Light Fringe Analysis

Pawłowski, M.; Sakano, Youhei; Miyamoto, Yoko; Takeda, Mitsuo

doi:10.1109/cleopr.2005.1569856

Cited by 2 publications

(10 citation statements)

References 6 publications

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“…The working principle of Pawlowski et al's phasecrossing algorithm [21,22] is that the location of zero (which corresponds to the height information) is the singular point at which the phase of the interference signal contributed by different wavelengths of light is equal to each other. In Pawlowski et al's phasecrossing algorithm, it is assumed that a conventional white light source which its spectrum has only one dominant wavelength is used and the correlogram can be represented as follows:…”

Section: Improved Height Reconstruction Algorithmmentioning

confidence: 99%

“…Figure 10 compares the 1 μm step height measured by the phase-crossing algorithm [21,22] using the conventional white light source and the dual wavelength white LEDs. For an objective assessment, the measurement repeatability (in terms of the standard deviation in measuring the flat surface) and the accuracy of reconstructed profiles are further analyzed.…”

Section: Experiments and Verificationmentioning

confidence: 99%

“…10. Comparing the simulated 1 μm step height measured by the phase-crossing algorithm [21,22] using (a) the conventional white light source and (b) the dual wavelength white LED with the BY ratio of 0.59, 1.14, and 1.60. Fig.…”

Section: Experiments and Verificationmentioning

confidence: 99%

“…11. Comparing the performance of the phase-crossing algorithm [21,22] using different light sources in terms of (a) the measurement repeatability (in terms of the standard deviation), the standard deviation of a perfectly flat surface is zero and (b) the measurement accuracy, the ideal value is 1 μm. Fig.…”

Section: Experiments and Verificationmentioning

confidence: 99%

“…Figure 12 compares the 10 μm step height measured by the phase-crossing algorithm [21,22] using the conventional white light source and the dual wavelength white LED with the BY ratio of 1.60 (LXHL-LW6C by LumiLEDs). The experimental result shows that the performance of the phasecrossing algorithm is improved by using the dual wavelength white LED: (1) In terms of the measurement repeatability, the standard deviation for measuring flat surface is 2.17 nm when using the dual wavelength white LED compared to 26.24 nm when using the conventional white light and (2) In terms of the measurement accuracy, the difference from the nominal value of the standard step height is smaller when using the dual wavelength white LED: the step height value is 10.09 μm when measured using the dual wavelength white LED compared to 10.18 μm when measured using the conventional white light.…”

Section: Experiments and Verificationmentioning

confidence: 99%

See 4 more Smart Citations

Harnessing spectral property of dual wavelength white LED to improve vertical scanning interferometry

Chong

Soh

2013

Appl. Opt.

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Unlike a conventional white light source that emits a continuous and broad spectrum of light, the dual wavelength white light emitting diode (LED) generates white light by mixing blue and yellow lights, so there are two distinct peaks in its intensity spectrum. Prior works had shown that the spectral property of the dual wavelength white LED can affect the vertical scanning interferometry negatively if the spectral effects are not compensated. In this paper, we shall examine this issue by modeling the spectral property and variation of the dual wavelength white LED, followed by investigating its effects on the interference signal of vertical scanning interferometry. Instead of compensating the spectral effects of the dual wavelength white LED, we harness its spectral property to improve the performance of a phase-based height reconstruction algorithm in vertical scanning interferometry.

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Section: Improved Height Reconstruction Algorithmmentioning

confidence: 99%

Section: Experiments and Verificationmentioning

confidence: 99%

Section: Experiments and Verificationmentioning

confidence: 99%

Section: Experiments and Verificationmentioning

confidence: 99%

Section: Experiments and Verificationmentioning

confidence: 99%

See 3 more Smart Citations

Harnessing spectral property of dual wavelength white LED to improve vertical scanning interferometry

Chong

Soh

2013

Appl. Opt.

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Spectral effects of phosphor-based white light-emitting-diode (LED) in coherence scanning interferometry

Chong¹

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Coherence scanning interferometry (CSI) is also known as white-light interferometry (WLI) and vertical scanning interferometry (VSI). It is a non-contact three-dimensional surface measurement technique that provides an accuracy of up to nanometer level and a measurement range of up to a few hundred micrometers. The principle of coherence scanning interferometry can be briefly summarized as follows: First, the light from a single source is split and channeled into the two arms of interferometer, where the test sample is placed at the end of one arm and a reference mirror is placed at the accuracy of this model is benchmarked against computationally intensive counterparts and verified by experiments. 2. The investigation of the spectral properties of high power phosphor-based white LED and their effects in coherence scanning interferometry. We showed that phosphorbased white LED degrades the performance of coherence scanning interferometry. 1.4. Organization of the report The rest of this thesis is organized as follows: not compensated. As such, we propose a method to compensate the spectral effects. Other than these, we also present a theoretical explanation of the distinctive feature which can be used to predict and manipulate the interference signal (and its fringe contrast function) by spectral manipulation. Chapter 5 presents an implementation study where the spectral effects of phosphor-based white LED are harnessed, instead of being compensated, to improve the performance of a phase-based height reconstruction algorithm. We analyze how the phase-based reconstruction algorithm takes advantages of the spectral property of phosphor-based white

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Phase-Crossing Algorithm for White-Light Fringe Analysis

Cited by 2 publications

References 6 publications

Harnessing spectral property of dual wavelength white LED to improve vertical scanning interferometry

Harnessing spectral property of dual wavelength white LED to improve vertical scanning interferometry

Spectral effects of phosphor-based white light-emitting-diode (LED) in coherence scanning interferometry

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