Light Field Superresolution Reconstruction in Computational Photography

2020 ◽

Vol V-2-2020 ◽

pp. 633-640

Author(s):

T. Fuse ◽

Y. Kajihara

Keyword(s):

Rigid Body ◽

Light Field ◽

Computational Photography ◽

Measurement Time ◽

3D Measurement ◽

3D Measurements ◽

Calculation Processing ◽

Future Work ◽

Shape From Focus

Abstract. In recent years, the demand for inexpensive, simple, and highly accurate 3D measurement has been increasing. Representative methods, photogrammetry, and shape from focus (SfF) have limitations in terms of measurement time and labour. In order to solve them, computational photography (CP) has been proposed. A light field camera, based on CP, has also been developed. It has a feature to acquire multi-view and multi-focus images simultaneously in one shot. It is possible to perform 3D measurements with less time and labour for photographing and calculation processing using these images. In this study, we combined the photogrammetry as applied to multi-view images with the SfF as applied to multi-focus images using a light field camera. We applied the proposed method to a rigid body and verified its accuracy. We confirmed that the proposed method achieved more accurate results than the photogrammetry and the SfF method. Furthermore, we applied the proposed method to screws and cracks on walls of buildings and affirmed its applicability. Finally, we suggested future work on the developed method.

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Polarized Light Field Imaging for Single-Shot Reflectance Separation

Sensors ◽

10.3390/s18113803 ◽

2018 ◽

Vol 18 (11) ◽

pp. 3803 ◽

Cited By ~ 2

Author(s):

Jaewon Kim ◽

Abhijeet Ghosh

Keyword(s):

Light Field ◽

Polarized Light ◽

Angular Separation ◽

Single Scattering ◽

Computational Photography ◽

Single Shot ◽

Specular Reflectance ◽

Structured Lighting ◽

Separation Results ◽

Imaging Conditions

We present a novel computational photography technique for single-shot separation of diffuse/specular reflectance, as well as novel angular domain separation of layered reflectance. We present two imaging solutions for this purpose: two-way polarized light-field (TPLF) imaging and four-way polarized light-field (FPLF) imaging. TPLF imaging consists of a polarized light-field camera, which simultaneously captures two orthogonal states of polarization. A single photograph of a subject acquired with the TPLF camera under polarized illumination then enables standard separation of diffuse (depolarizing) and polarization preserving specular reflectance using light-field sampling. We further demonstrate that the acquired data also enable novel angular separation of layered reflectance including separation of specular reflectance and single scattering in the polarization preserving component, as well as separation of shallow scattering from deep scattering in the depolarizing component. FPLF imaging further generalized the functionality of TPLF imaging under uncontrolled unpolarized or partially polarized illumination such as outdoors. We apply our approach for efficient acquisition of facial reflectance including diffuse and specular normal maps and novel separation of photometric normals into layered reflectance normals for layered facial renderings. We validate our proposed single-shot layered reflectance separation under various imaging conditions and demonstrate it to be comparable to an existing multi-shot technique that relies on structured lighting while achieving separation results under a variety of illumination conditions.

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Computational photography with plenoptic camera and light field capture: tutorial

Journal of the Optical Society of America A ◽

10.1364/josaa.32.002021 ◽

2015 ◽

Vol 32 (11) ◽

pp. 2021 ◽

Cited By ~ 60

Author(s):

Edmund Y. Lam

Keyword(s):

Light Field ◽

Computational Photography ◽

Plenoptic Camera

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Image processing algorithms for a light-field camera and their application for optical flow diagnostics

Numerical Methods and Programming (Vychislitel'nye Metody i Programmirovanie) ◽

10.26089/nummet.v17r321 ◽

2016 ◽

pp. 224-233

Author(s):

А.В. Серёдкин ◽

М.П. Токарев

Keyword(s):

Spatial Resolution ◽

Optical Sensors ◽

Light Field ◽

Three Dimensional ◽

Fluid Flows ◽

Computational Photography ◽

Gas Flows ◽

Experimental Fluid Mechanics ◽

Measurement Area ◽

Experimental Fluid

Применение современных оптико-электронных приборов расширяет возможности исследований в области экспериментальной механики жидкостей. Методы вычислительной фотографии за счет использования основанных на ней устройств постепенно проникают в различные области науки и техники. Камера светового поля может использоваться для регистрации трехмерных распределений скорости в потоках жидкости и газа там, где расположение нескольких панорамных оптических сенсоров затруднено за счет ограничения оптического доступа и вибраций. В работе исследованы возможности пленоптической системы, состоящей из доступной на рынке промышленной камеры светового поля применительно для диагностики течений жидкости и газа. Предложен и протестирован новый программный алгоритм для вычисления карты глубины регистрируемой измерительной области. Согласно полученным результатам, пространственное разрешение метода по глубине при использовании 11 мегапиксельного сенсора достигает 1/40 от глубины резкости оптической системы. Указанный метод был использован для измерения 3D-полей скорости турбулентной струи внутри щелевого канала по всей его глубине. В будущем количество задач, в которых целесообразно использование пленоптических устройств с высоким пространственным разрешением, будет расти. Application of modern optoelectronic devices extends research in the field of experimental fluid mechanics. The methods of computational photography gradually penetrate into the various fields of science and technology due to using devices based on these methods. A light-field camera can be used to register a three-dimensional velocity distribution in fluid flows where the location of several panoramic optical sensors is difficult because of restrictions in an optical access and vibrations. in this paper we study the possibility of using a plenoptic system consisting of an industrial light-field camera to diagnose liquid and gas flows. A new software algorithm for computing a depth field of a measurement area is proposed. According to the obtained results, the spatial resolution of the method by depth reaches 1/40th of the depth of the field of the optical system when using 11 MP sensor. This method was used to measure 3D velocity fields of a turbulent jet inside a slot channel throughout its depth. In the future, the number of applications will grow for the cases where the use of plenoptic devices with high spatial resolution is appropriate.

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The Impact of Light Polarisation on Light Field of Scenes with Multiple Reflections

Light & Engineering ◽

10.33383/2019-023 ◽

2020 ◽

pp. 108-115 ◽

Cited By ~ 1

Author(s):

Vladimir P. Budak ◽

Anton V. Grimaylo

Keyword(s):

Mathematical Model ◽

Light Field ◽

Global Illumination ◽

Multiple Reflections ◽

Software Environment ◽

The Monte Carlo Method ◽

Mueller Matrices ◽

Volume Integration ◽

The Impact

The article describes the role of polarisation in calculation of multiple reflections. A mathematical model of multiple reflections based on the Stokes vector for beam description and Mueller matrices for description of surface properties is presented. On the basis of this model, the global illumination equation is generalised for the polarisation case and is resolved into volume integration. This allows us to obtain an expression for the Monte Carlo method local estimates and to use them for evaluation of light distribution in the scene with consideration of polarisation. The obtained mathematical model was implemented in the software environment using the example of a scene with its surfaces having both diffuse and regular components of reflection. The results presented in the article show that the calculation difference may reach 30 % when polarisation is taken into consideration as compared to standard modelling.

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