Temporal phase unwrapping using orthographic projection

Petković, Tomislav; Pribanić, Tomislav; Đonlić, Matea

doi:10.1016/j.optlaseng.2016.09.006

Cited by 26 publications

(10 citation statements)

References 43 publications

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“…In order to establish per block correspondences in the camera-projector system, we use multiple sine patterns which are shifted in phase (i.e. multiple phase shift, MPS approach [29,30]). MPS patterns are projected onto the scene independently from the CS measurement patterns and captured by the Lytro camera.…”

Section: Measurement Processmentioning

confidence: 99%

Overcoming spatio-angular trade-off in light field acquisition using compressive sensing

et al. 2020

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In contrast to conventional cameras which capture a 2D projection of a 3D scene by integrating the angular domain, light field cameras preserve the angular information of individual light rays by capturing a 4D light field of a scene. On the one hand, light field photography enables powerful post-capture capabilities such as refocusing, virtual aperture, depth sensing and perspective shift. On the other hand, it has several drawbacks, namely, high-dimensionality of the captured light fields and a fundamental trade-off between spatial and angular resolution in the camera design. In this paper, we propose a compressive sensing approach to light field acquisition from a sub-Nyquist number of samples. Using an off-the-shelf measurement setup consisting of a digital projector and a Lytro Illum light field camera, we demonstrate the efficiency of the compressive sensing approach by improving the spatial resolution of the acquired light field. This paper presents a proof of concept with a simplified 3D scene as the scene of interest. Results obtained by the proposed method show significant improvement in the spatial resolution of the light field as well as preserved post-capture capabilities.

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Section: Measurement Processmentioning

confidence: 99%

Overcoming spatio-angular trade-off in light field acquisition using compressive sensing

et al. 2020

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“…The wrapped phase is then unwrapped using one of the well known phase unwrapping algorithms [19,20,21] to obtain projector's coordinate PRJ which is required to reconstruct the surface profile via triangulation [22]. …”

Section: A Short Review Of Traditional Fringe Projection Profilometrymentioning

confidence: 99%

“…c. Recover the wrapped phase A of @-th projector as the negative phase of the @-th spectral component. d. Unwrap the wrapped phase A using any of the unwrapping algorithms from [19,20,21]. e. Compute projector coordinate A from the unwrapped phase.…”

Section: Proposed Multiplexing Using Temporal Phase-shiftsmentioning

confidence: 99%

“…We have selected a multiple-phase shifting (MPS) unwrapping strategy [19] for phase unwrapping. The minimal number of frequencies required for unwrapping is two and the minimal number of frames required for separating projector contributions is seven; this gives the minimum of fourteen frames which are required for 3D reconstruction.…”

Section: Experimental Recordingsmentioning

confidence: 99%

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Multi-Projector Multi-Camera Structured Light 3D Body Scanner

Petković¹,

Pribanić²,

Đonlić³

et al. 2017

Proceedings of 3DBODY.TECH 2017 - 8th International Conference and Exhibition On 3D Body Scanning and Processing Technologies,

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Human body scanners using structured light are usually comprised of one projector which provides a limited view of the body surface due to limited field-of-view. To scan the whole surface of a human body multiple projectors must be used. Using more than one projector in a structured light scanner is typically difficult due to inter-projector interferences which make surface reconstruction a hard task. We propose to use temporal phase-shifts to enable multiplexing in fringe-projection profilometry. In our approach each projector projects a sinusoidal fringe pattern having its own specifically chosen set of temporal phase shifts so for a system of projectors all temporal phase shifts together comprise a DFT basis. Such choice of temporal phase shifts enables simple and efficient separation of the combined pattern into the contributions of each projector. The proposed approach places no constraints on the number of projectors and on spatial projector placement. We demonstrate the applicability of the proposed approach on a prototype human body scanner using three projectors and six cameras.

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“…The robust CRT claims that even though every remainder has a small error, a large nonnegative integer can be robustly reconstructed in the sense that the reconstruction error is upper bounded by the bound of the remainder errors. Beyond these applications aforementioned, the robust CRT has offered useful applications in multi-wavelength optical measurement [25]- [27], distance or velocity ambiguity resolution [28]- [31], fault-tolerant wireless sensor networks [32]- [34], error-control neural coding [35]- [37], etc. It is worth pointing out that the (robust) CRT has been generalized to (robustly) reconstruct multiple large nonnegative integers from their unordered remainder sets as well [38]- [44].…”

Section: Introductionmentioning

confidence: 99%

Exact and Robust Reconstructions of Integer Vectors Based on Multidimensional Chinese Remainder Theorem (MD-CRT)

Xiao,

Xia,

Wang

2020

Preprint

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The robust Chinese remainder theorem (CRT) has been recently proposed for robustly reconstructing a large nonnegative integer from erroneous remainders. It has found many applications in signal processing, including phase unwrapping and frequency estimation under sub-Nyquist sampling. Motivated by the applications in multidimensional (MD) signal processing, in this paper we propose the MD-CRT and robust MD-CRT for integer vectors. Specifically, by rephrasing the abstract CRT for rings in number-theoretic terms, we first derive the MD-CRT for integer vectors with respect to a general set of integer matrix moduli, which provides an algorithm to uniquely reconstruct an integer vector from its remainders, if it is in the fundamental parallelepiped of the lattice generated by a least common right multiple of all the moduli. For some special forms of moduli, we present explicit reconstruction formulae. Moreover, we derive the robust MD-CRT for integer vectors when the remaining integer matrices of all the moduli left divided by their greatest common left divisor (gcld) are pairwise commutative and coprime. Two different reconstruction algorithms are proposed, and accordingly, two different conditions on the remainder error bound for the reconstruction robustness are obtained, which are related to a quarter of the minimum distance of the lattice generated by the gcld of all the moduli or the Smith normal form of the gcld.

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Temporal phase unwrapping using orthographic projection

Cited by 26 publications

References 43 publications

Overcoming spatio-angular trade-off in light field acquisition using compressive sensing

Overcoming spatio-angular trade-off in light field acquisition using compressive sensing

Multi-Projector Multi-Camera Structured Light 3D Body Scanner

Exact and Robust Reconstructions of Integer Vectors Based on Multidimensional Chinese Remainder Theorem (MD-CRT)

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