Diffusers in digital holography

Bräuer, Ralf; Wyrowski, Frank; Bryngdahl, Olof

doi:10.1364/josaa.8.000572

Cited by 96 publications

(34 citation statements)

References 15 publications

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“…To diffuse the light wave of an object, a method is used that mainly adds white noise to light waves of object surfaces as distributions of phase differences [14]. In this method, a light wave of an object surface advances in any direction and reflectance distributions become a perfect diffuse reflection.…”

Section: B Conventional Methodsmentioning

confidence: 99%

Calculation method of reflectance distributions for computer-generated holograms using the finite-difference time-domain method

et al. 2011

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The research on reflectance distributions in computer-generated holograms (CGHs) is particularly sparse, and the textures of materials are not expressed. Thus, we propose a method for calculating reflectance distributions in CGHs that uses the finite-difference time-domain method. In this method, reflected light from an uneven surface made on a computer is analyzed by finite-difference time-domain simulation, and the reflected light distribution is applied to the CGH as an object light. We report the relations between the surface roughness of the objects and the reflectance distributions, and show that the reflectance distributions are given to CGHs by imaging simulation.

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Section: B Conventional Methodsmentioning

confidence: 99%

Calculation method of reflectance distributions for computer-generated holograms using the finite-difference time-domain method

et al. 2011

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“…As a result, full random phases usually cause speckles in the reconstruction. In this paper, speckle-free quasirandom phase distribution proposed as a digital diffuser in Fourier holograms [17] is used for the phase distribution.…”

Section: B Surface Functionsmentioning

confidence: 99%

Extremely high-definition full-parallax computer-generated hologram created by the polygon-based method

2009

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A large-scale full-parallax computer-generated hologram (CGH) with four billion (2 16 × 2 16 ) pixels is created to reconstruct a fine true 3D image of a scene, with occlusions. The polygon-based method numerically generates the object field of a surface object, whose shape is provided by a set of vertex data of polygonal facets, while the silhouette method makes it possible to reconstruct the occluded scene. A novel technique using the segmented frame buffer is presented for handling and propagating large wave fields even in the case where the whole wave field cannot be stored in memory. We demonstrate that the fullparallax CGH, calculated by the proposed method and fabricated by a laser lithography system, reconstructs a fine 3D image accompanied by a strong sensation of depth.

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“…Their reflectance distributions become perfectly diffuse reflections, and the whole object can be seen although there is some speckle noise. To reduce the speckle noise, Bräuer et al [9] generated the phase difference by limiting the spread angle of reflected light, and its reflectance distribution became a nearly perfect diffuse reflection.…”

Section: Previous Workmentioning

confidence: 99%

Calculation method for computer-generated holograms considering various reflectance distributions based on microfacets with various surface roughnesses

2011

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Computer-generated holograms are generated by three-dimensional technology, and they can be used to reconstruct natural and virtual objects by simulating light waves based on holography. This research was an improvement on previous work that took into consideration reflectance distributions from the various roughnesses of objects. The previous work generated roughness by using a simple model, so that only simple roughness was generated. The proposed method generated more complex roughness than that in the previous work, and the influence of roughness on the reflectance distributions was investigated. Computer simulations, which were compared with the reflectance distributions from the various roughnesses, were carried out. Moreover, computational and optical reconstructions were carried out as examples of reconstructions. As a result of the experiments, we confirmed that the various roughnesses actually influenced the reflectance distributions.

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Diffusers in digital holography

Cited by 96 publications

References 15 publications

Calculation method of reflectance distributions for computer-generated holograms using the finite-difference time-domain method

Calculation method of reflectance distributions for computer-generated holograms using the finite-difference time-domain method

Extremely high-definition full-parallax computer-generated hologram created by the polygon-based method

Calculation method for computer-generated holograms considering various reflectance distributions based on microfacets with various surface roughnesses

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