Diffraction specific coherent panoramagrams of real scenes
Author(s):
James Barabas;
Sundeep Jolly;
Daniel E. Smalley;
V. Michael Bove Jr.
Show Abstract
We have previously introduced the Diffraction Specific Coherent Panoramagram - a multi-view holographic stereogram
that provides correct visual accommodation as well as smooth motion parallax with far fewer views than a normal stereogram.
This method uses scene depth information to generate directionally-varying wavefront curvature, and can be computed
at interactive rates using off-the-shelf graphics processors. In earlier work we used z-buffer information associated
with parallax views rendered from synthetic graphics models; in this paper we demonstrate the computation of Diffraction
Specific Coherent Panoramagrams of real-world scenes captured by cameras.
Holographic stereogram using camera array in dense arrangement
Author(s):
Kenji Yamamoto;
Ryutaro Oi;
Takanori Senoh;
Yasuyuki Ichihashi;
Taiichiro Kurita
Show Abstract
Holographic stereograms can display 3D objects by using ray information. To display high quality representations of real 3D objects by using holographic stereograms, relatively dense ray information must be prepared as the 3D object information. One promising method of obtaining this information uses a combination of a camera array and view interpolation which is signal processing technique. However, it is still technically difficult to synthesize ray information without visible error by using view interpolation. Our approach uses a densely arranged camera array to reduce this difficulty. Even though view interpolation is a simple signal processing technique, the synthesized ray information produced by this camera array should be adequate. We designed and manufactured a densely arranged camera array and used it to generate holographic stereograms.
Compression of digital hologram for 3D object using wavelet-bandelets transform
Author(s):
Le Thanh Bang;
Quang Duc Pham;
Zulfiqar Ali;
Jae-Hyeung Park;
Nam Kim
Show Abstract
In the transformation based compression algorithms of digital hologram for three-dimensional object, the balance
between compression ratio and normalized root mean square (NRMS) error is always the core of algorithm development.
The wavelet transform method is efficient to achieve high compression ratio but NRMS error is also high. In order to
solve this issue, we propose a hologram compression method using Wavelet-Bandelets transform. Our simulation and
experimental results show that the Wavelet-Bandelets method has a higher compression ratio than Wavelet methods and
all the other methods investigated in this paper, while it still maintains low NRMS error.
Accelerating digital holographic de-convolution microscopy using CUDA's nested concurrency
Author(s):
Zulfiqar Ali;
Mei-Lan Piao;
Jae-Hyeung Park;
Nam Kim
Show Abstract
In this study we have exploited the parallel nature of the computations involved in the process of numerical volume
reconstruction of three-dimensional digital holographic microscopy and utilized CUDA enabled graphics processing
unit (GPU) to accelerate the reconstruction process. We have recorded holograms of the 3D specimen using CCD
with inline setup, then using GPU we have initiated CUDA kernels for de-convolution of the diffraction integral for
multiple depth planes in parallel, speeding up the reconstruction of the entire volume. Our experimental results
confirm that GPU reconstruction is much faster than that of central processing unit (CPU).
Calculation method for CGH considering smooth shading with polygon models
Author(s):
Kazuhiro Yamaguchi;
Tsubasa Ichikawa;
Yuji Sakamoto
Show Abstract
Computer generated hologram (CGH) can reconstruct 3-D objects as perfectly well as can optical holography.
However, the reality of the reconstructed objects is lower than that of optical holography.
This problem is caused by a lack of rendering techniques for CGH.
To improve the reality of objects reconstructed by CGH, we have studied rendering techniques in computer graphics such as reflectance distributions for CGH.
Reflectance distributions represent a material of an object surface, and objects with various reflectance distributions are reconstructed by using the previous work.
In this paper, we improved on the previous work by using polygon models and shading techniques for CGH.
The shading technique is also established in computer graphics, and it can render objects having a smooth luminance without using many polygons.
A polygon model made up of many polygons is rendered the same as a polygon model made up of few polygons by using shading technique.
However, the calculation time of CGH increases with the number of polygon, so it is necessary for CGH to reconstruct objects of high reality from polygon models made up of few polygons.
Taking into account the shading technique, polygon models with few planer patches are reconstructed with smooth luminance.
We carried out computational and optical reconstructions as experiments.
We report the results of these experiments and show the effectiveness of our proposed method.
A method of calculating reflectance distributions for CGH with FDTD using the structure of actual surfaces
Author(s):
Tsubasa Ichikawa;
Yuji Sakamoto;
Agus Subagyo;
Kazuhisa Sueoka
Show Abstract
Computer Generated Hologram (CGH) is generated by computer simulation using the diffraction theory.
However, the development of a rendering technology to display images beautifully like in the field of Computer Graphics is scarce.
The research for reflectance distribution is particularly so few, that the texture of each material cannot be expressed.
Therefore we propose a calculation method for calculating reflectance distribution for CGH that uses the finite-difference time-domain (FDTD) method.
In this method, reflected light from an uneven surface made in the computer is analyzed by FDTD simulation, and a reflected light distribution is applied to CGH as object light.
To make the outer structure identical to the real objects, the outer structure of the real objects was measured with an atomic force microscope (AFM).
By using the measurement data, peculiar reflectance distributions of the materials are given for CGH.
It was confirmed that the variation of the surface roughness of the measured sample affected the three-dimensional images in optical reconstruction.
Moreover, we report the relation between the surface roughness of samples and the reflectance distribution.
Instantaneous measurement of surface shape with high accuracy by one-shot digital holography
Author(s):
Yoshihide Iwayama;
Kunihiro Sato
Show Abstract
A new method is proposed for instantaneous measurement of 3-D shape of moving objects with rough surface by using
one-shot digital holography. The principle of proposed method consists of projection of interference fringes with a
constant period on surfaces, one-shot recording of the complex-amplitude in-line hologram, elimination of speckle from
reconstructed images, and calculation of depth from focus. The acquisition time is less than 1 micro-second needed for
recording one hologram. Speckles appeared in reconstructed images are eliminated into a low level by filtering.
Following the method of depth of focus, we can precisely determine 3-D position of each point on the surface. Accuracy
higher than 0.01% is obtained in the experiment of depth measurement because of low-level speckles.
Wide viewing-zone-angle full-color electronic holography system using very high resolution liquid crystal display panels
Author(s):
Takanori Senoh;
Tomoyuki Mishina;
Kenji Yamamoto;
Ryutaro Oi;
Taiichiro Kurita
Show Abstract
A wide viewing-zone-angle full-color electronic holography reconstruction system is developed. Time division
multiplexing of RGB color light and space division multiplexing of viewing-zone-angles are adopted to keep the optical
system compact. Undesirable light such as illumination light, phase conjugate light, and high-order diffraction light are
eliminated by half-zone-plate hologram generation and single sideband beam reconstruction. Color aberration and
astigmatism caused by the reproduction optical system are analyzed and reduced. The developed system expands
viewing-zone-angle of full-color holographic image three times wider than the original, suppressing undesirable light,
color aberration, and astigmatism.
DYI digital holography
Author(s):
Stanislovas Zacharovas;
Andrej Nikolskij;
Jevgenij Kuchin
Show Abstract
We have created a programming tool which uses image data provided by webcam connected to personal computer and
gives user an ability to see the future digital hologram preview on his computer screen, before sending video data to
holographic printing companies. In order to print digital hologram, one needs to have a sequence of images of the same
scene taken from different angles and nowadays web cameras - stand-alone or incorporated into mobile computer, can be
an acceptable source of such image sequences. In this article we are describing this DIY holographic imaging process in
details.
Color holography for museums: bringing the artifacts back to the people
Author(s):
Hans I. Bjelkhagen;
Ardie Osanlou
Show Abstract
Color display holography, which is the most accurate imaging technology known to science, has been used to produce
holographic images for display of artifacts in museums. This article presents the 'Bringing the Artifacts back to the
people' project. Holograms of twelve different artifacts were recorded using the single-beam Denisyuk color reflection
hologram technique. 'White' laser light was produced from three combined cw RGB lasers: a red krypton-ion laser, a
green frequency-doubled Nd-YAG laser, and an argon-ion laser. Panchromatic ultra-fine-grain silver halide materials
were used for the recording of the holograms. During 2009 the artifacts were brought to St Asaph in Wales at the Centre
for Modern Optics, to undergo holographic recording. One of the recorded artifacts included a 14,000-year-old
decorated horse jaw bone from the ice age, which is kept at British Museum in London. The recorded color holograms
of this object and others have been arranged in a touring exhibition, the 'Virtual Artifacts Exhibition.' During 2010-
2011, this will be installed in a number of local museums in North Wales and surrounding areas.
Artistic expression in the development of new technology for three dimensional imaging
Author(s):
Sandra Oliveira;
Martin Richardson;
Isabel Azevedo
Show Abstract
The medium of holography offers many new creative possibilities for the development of kinetic art. In the search of
new forms of image display we examine new methods of capturing Three Dimensional animated images. Expression in
new forms of visualisation leads to new methods for exploration auto-stereoscopic displays, three-dimensional imaging
and holography. Artists have long combined cameras together to explore the human body as form and space and this
paper sets out the potential of some of these techniques and in particular the technical potential of the use of multicamera
capture techniques. Artists such as Tim Macmillan1 (2010) and Dayton Taylor2 (1997) use multi-lens cameras to
create the illusion of capturing space and time for different effects, such as frozen moment, live action and slow motion
(often seen as a cinemagraphic effect). However, their results are two-dimensional images made with a two-dimensional
image capture system. Previous research on the interaction between art and technology has been based on twodimensional
video art. This paper outlines a method of three-dimensional video capture to explore three-dimensional
space and the human body. The stereoscopic specialist Ray Zone3 has written about the evolution of 3-D technology and
3-D film. Zone examines the development of these 3-D techniques and demonstrates the connection between two fields.
This research extends our knowledge of Three Dimensional moving image as an art form. In the new art world,
Holography has become a method increasingly used to develop kinetic art. In the search of new forms of display and
image capture, we examine new techniques such as 3-D, including auto-stereoscopic display, three-dimensional imaging
and holography.
Changing thoughts: a series of digital art holograms
Author(s):
Isabel Azevedo;
Martin Richardson
Show Abstract
Light is the one key essential quality of holography and as such holograms are morphologically closer to 'Optical',
'Kinetic' and 'Light Art'. In my attempt to explore this 'Kinetic' feature I collaborated Martin Richardson in the Modern
Holography Program at DeMontfort University, in Leicester between March 2010 and 2011, to produce a series of
digital art holograms and lenticulars with an open and experiential reference to light capture as energetic element. These
holograms were filmed using a 35mm digital camera on a moving rail system and are as such 'Stereogram's', then
printed by GEOLA in Lithuania as reflection holograms measuring 50cm x 60cm.
The title of this series of digital stereographic holograms is 'Changing Thoughts'. They allude to the interrelationship the
observer has in assuming an understanding of what they see, only to suddenly change when they find out that what they
are seeing is actually something quite different to what they had understood.
Much critical theorization, in recent times, has focused on the body and related to the work of Merleau-Ponty. And to
António Damásio, the word images, means mental patterns with each sensorial way. Not only related at "visual" images
nor static objects. But also sonorous images, or body inside images like those described by Einstein when he was trying
to solve problems.
3D holographic portraits: presence and absence
Author(s):
Rosa Maria Oliveria;
Luís Miguel Bernardo
Show Abstract
Authors writing about the portrait insist on the status of extending the model image portrayed beyond the absence and
even death. The portrait also has this ability and suggests immortality. The picture suspends the time, making the absent
present.
The portrait has been, over time, one of the themes mostly used in art. No wonder that in holography it is an important
subject as well. The face is a body area of privileged communication and expression. It expresses emotions through
looks, smiles, movements and expressions. Being Holography, so far, the recording technology that represents the object
most similar to the original, with the same parallax, we may fall into a mimetic representation of reality. On Art
Holography even by following paths already traversed, the resulting holograms are always different because of the
unique concept that each artist-holographer puts into his work. As with any other artistic technology, each artist uses the
medium differently and with different results.
Speckle reduction in holography: a using time-multiplexing technique
Author(s):
Masahito Yokouchi;
Takayuki Kurihara;
Yasuhiro Takaki
Show Abstract
This study proposes a time-multiplexing technique to eliminate speckles from hologram reconstruction. The object
points constituting a reconstructed image were divided into several groups that consisted of sparse object points. These
object point groups were then sequentially displayed. The sparseness and temporal summation suppressed speckle
generation. The object point group decomposed into multiple bit planes to represent the gray levels of the object points,
and binary holograms were generated from the bit plane patterns by using the half zone plate technique. The binary
holograms were displayed using a high-speed spatial light modulator (SLM), which is illuminated by a light whose
intensity is appropriately modulated. We used a digital micromirror device with a resolution of 1,024 × 768 as a highspeed
SLM. The reconstructed image consisted of 8 × 4 object point groups. Each object point group consisted of 16 ×
24 object points, and each object point was generated by a half zone plate displayed by 64 × 32 pixels. Each object point
group decomposed into eight bit planes; thus the reconstructed image was displayed with 256 gray levels. The
reconstructed images consisting of 128 × 96 object points were displayed at a frame rate of 52 Hz.
Quantitative quality measure based on light wave distribution to access 3D display
Author(s):
Yuji Sakamoto;
Fumio Okuyama
Show Abstract
There are a lot of three-dimensional (3D) displaying methods such as stereoscopy, integral photography, holography,
etc. These technologies have different 3D vision properties and 3D image qualities. Conventionally,
biological responsiveness is measured by using an actual 3D display in order to evaluate image qualities of 3D
displaying method. It is required quantitative quality measure for 3D images for quantitative evaluation, which
are useful for comparing 3D image quality and a design of a new display system. In this paper, we propose
quality measures for 3D images named volume signal to noise ratio (VSNR), which is a three-dimensionally
extended signal to noise ratio (SNR). A 3D display produces light wave distributions in 3D space, which makes
observers view 3D image illusions. The VSNR measures error of light wave distributions between generated by
actual objects and produced by a 3D display. The light wave distribution is including various factors for 3D
perception of human such as resolution of reconstructed images, visual fields, motion parallax, and depth of field.
The VSNR evaluates these 3D perception factors totally. We were carried out the experiments to certificate the
efficiency of the VSNR. 3D images represented electro-holographic display and integral photographic displays
were evaluated by the VSNR. The results indicated that the electro-holographic display has better quality than
integral photographic display, but speckle noise deteriorates the 3D image quality.
Holographic recording aspects of high-resolution Bayfol HX photopolymer
Author(s):
Horst Berneth;
Friedrich K. Bruder;
Thomas Fäcke;
Rainer Hagen;
Dennis Hönel;
David Jurbergs;
Thomas Rölle;
Marc-Stephan Weiser
Show Abstract
We have been developing a new class of recording materials for volume holography, offering the advantages of full
color recording and depth tuning without any chemical or thermal processing, combined with low shrinkage and
detuning. These photopolymers are based on the two-chemistry concept in which the writing chemistry is dissolved in a
preformed polymeric network. This network gives the necessary mechanical stability to the material prior to recording.
In this paper we describe several aspects of holographic recording into Bayfol® HX which are beneficial for its effective
use and discuss them within a more elaborate reaction-diffusion model. Inhibition phenomena and the influence of precure
are studied within this model and are investigated experimentally for single hologram recording and angular
multiplexed hologram recordings. Also the dark reaction after the exposure period and the minimum allowable waiting
time for full hologram formation are addressed. The proper understanding of these phenomena is important for the
optimal usage of these new materials, in for example step-and-repeat mass production of holograms.
Photorefractive amplification at high frequencies
Author(s):
Russell M. Kurtz;
Weixing Lu;
Judy Piranian;
Albert O. Okorogu
Show Abstract
Photorefractive optical amplification, while useful, is a slow process. Under some circumstances, however, it amplifies
optical signals effectively even when one is modulated at a relatively high frequency. We determine the reasons for this
capability (what we have called the "Fast Photorefractive Effect") and analyze its enhanced bandwidth, improvements
over standard photorefractivity, and limitations.
A review of selected technological applications of DCG holograms
Author(s):
Christo G. Stojanoff
Show Abstract
The subject matter of this presentation is to demonstrate the engineering applications of holographic optical elements
(HOEs) fabricated in dichromated gelatin (DCG) films exhibiting enhanced properties. The composition, structure and
the physical, chemical and optical properties of the DCG-film are briefly described in the introduction that is followed by
detailed discussion of the developing processes used to achieve the necessary holographic characteristics required by the
various applications. Other procedures are used to achieve explicit objectives, e.g., controlling the spectral characteristics
of the HOE by inorganic and/or organic additives and using filler material to enhance the UV or IR performance. Stress
induced by environmental forces, e.g., wind, or by mechanical strain also changes the performance of the HOE and may
be exploited in engineering applications. The optical characteristics of the HOE are also modified by internally induced
stress, such as changing the water content of the polymer or using cross-linking agents to modify and harden the gelatin
matrix. The formation of thermal or density gradients in the gelatin film during the coating process or at some stage of
the hologram development have also an effect on the holographic properties for they determine the conformational state
and the mechanical strength of the gelatin film. The ratio between the coiled and the helical structures in the gelatin
matrix determines the optical and mechanical properties of the holographic film. Multiple exposures are used to record
up to four holograms in single DCG film that are used to reconstruct concurrently several monochrome or RGB beams.
Nanophotonic hierarchical hologram: hierarchical information processing and nanometric data retrieval based on nanophotonics
Author(s):
Naoya Tate;
Makoto Naruse;
Takashi Yatsui;
Tadashi Kawazoe;
Morihisa Hoga;
Yasuyuki Ohyagi;
Tokuhiro Fukuyama;
Yoko Sekine;
Mitsuru Kitamura;
Motoichi Ohtsu
Show Abstract
A nanophotonic hierarchical hologram works in both optical far-fields and near-fields, the former being associated
with conventional holographic images, and the latter being associated with the optical intensity distribution based on a
nanometric structure that is accessible only via optical near-fields. In principle, a structural change occurring at the
subwavelength scale does not affect the optical response functions, which are dominated by propagating light. Therefore,
the visual aspect of the hologram is not affected by such a small structural change on the surface, and retrieval in both
fields can be processed independently. We propose embedding a nanophotonic code, which is retrievable via optical
near-field interactions involving nanometric structures, within an embossed hologram. Due to the one-dimensional grid
structure of the hologram, evident polarization dependence appears in retrieving the code. Here we describe the basic
concepts, numerical simulations, and experimental demonstrations of a prototype nanophotonic hierarchical hologram
with a nanophotonic code and describe its optical characterization.
Phase shifting holographic interferometer for precise alignment measurements in packaging applications
Author(s):
Vladimir V. Nikulin;
Rahul Khandekar;
Vijit Bedi
Show Abstract
One of the main challenges in optoelectronic and photonic applications is the alignment accuracy after bonding of the
components is completed, especially if there are multiple single-mode alignments. Advanced applications often require
positioning accuracy of these components to be within a sub-micron range in order to avoid unacceptable signal
degradation. Also, there is a concern about the effects of certain processing techniques on component integrity. In all
cases, the extent to which a package is affected can only be evaluated by a measurement approach that allows detecting
misalignments/deformations on the order of 10nm. Unfortunately, many conventional techniques are virtually useless
when measurements are performed on diffuse objects, such as photonic packages. These limitations can be avoided using
holography, which facilitates recording and reconstruction of the optical waves reflected from any surface. In the process
of reconstruction it is possible to reproduce not only the amplitude of the reflected wave, but also its phase distribution,
which carries information about the distance to each point illuminated with light. An optical technique developed by our
group and presented in this paper is based on a holographic approach and combines the principles of holographic
interferometry and phase modulating adaptive optics.
Polarization-holographic diffraction element-based real-time imaging Stokes spectropolarimetry
Author(s):
George Kakauridze;
Barbara Kilosanidze
Show Abstract
The new method of imaging Stokes spectropolarimetry in real time on the basis of polarization-holographic element is
offered. Polarization-holographic element with complicated profile of anisotropy for the real-time complete analysis of
polarization state of light (all Stokes parameters) is developed. During diffraction the element decomposes light
incoming on them onto orthogonal circular and linear basis. The simultaneous measurement of the intensities in all
points of images in diffracted orders by means of CCD matrices and appropriate software allows to determine the spatial
distribution of a polarization state in the images of extended objects, and also the dispertion if this distribution.
Dynamic energy transfer in a polarization hologram at low intensity of working beams
Author(s):
George Kakauridze;
Barbara Kilosanidze
Show Abstract
The phenomenon of energy transfer is considered by means of dynamic polarization holograms. The use of higheffective
reversible polarization-sensitive media makes it possible to use beams with low intensities from CW lasers. For
amplification of energy transfer, the additional mechanical shift of the medium was used such that the phase shift would
be of optimal value π/2. The increase of the intensity of a weak beam up to 300% within the time of tens of milliseconds
was obtained. This approach gives the possible to amplify coherent light beams by relatively simple way including the
amplification of beams in communication systems.
Light induced anisotropy and gyrotropy in the media on the basis of azo indicators
Author(s):
Valentina Shaverdova;
Svetlana Petrova;
Anna Purtseladze;
Lado Tarasashvili;
Nino Obolashvili
Show Abstract
Azo indicators are well known in which when changing acidity they changes their properties. It was natural to expect
also their appreciable changes of their polarization properties. The results of the carried out experimental research in
recording media on the basis of azo indicators- homolog of the Methyl orange introduced into the polymeric matrix are
presented in this work. According to the technology developed by us, the samples for the reception of which solvents
with various degree of acidity, within values pH 1.68-12.45 have been created. Samples were irradiated by the light of
argon laser (488 nm) actinic for them. Measurement of light induced anisotropy was carried out on a registering recorder
and can be described by means of one parameter- the effective anisotropy. As standards the samples of dyes for the
reception of which neutral solvent was used have been considered. In a number of dyes the values of effective anisotropy
in alkaline and acid media exceed its values concerning corresponding standards. The higher homolog -Heptyl orange
and Benzyl orange which are weak or insoluble in water, become water-soluble when using solvents both with acid and
alkaline reaction. The interval of appearance of light induced anisotropy has been expanded. We have used the method of
the zero-ellipsometry for the research arising in the same samples light induced gyrotropy. Values of circular dichroism
and circular birefringence in investigated layers in neutral media have been calculated also at various values pH. In the
work the received results are discussed and analyzed.
Behavior of MTF parameter from corn honey holographic material at 473nm and 530nm
Author(s):
A. Olivares-Pérez;
I. Fuentes-Tapia;
R. Velazquez-Xique
Show Abstract
Basic study was realized, for the characterization of photosensitive material, a technique of angular
change between the incident beams that form the interference pattern was used. We obtaining some
graphics, where the material is related the space frequency with the energy, module transfer function
(MTF). The material that was characterized by this technique was Corn Honey. This material was
used as matrix, which was doped with potassium dichromate, as well as with halides of transition
metals, and they were exposed to wavelengths of 473 and 530 nm respectively.
Albumin holograms
Author(s):
M. J. Ordóñez-Padilla;
A. Olivares-Pérez;
R. Vega-Criollo;
L. R. Berriel-Valdos;
N. Y. Mejias-Brizuela
Show Abstract
A Characterization is made with performance analysis of new photosensitive films of albumin to certain
conditions for holographic recording based on interferometric array. We carried out the photo-oxidation
of gallus gallus albumin albumin chemically combining powdered sugar (Glass ®) to an aqueous solution
of ammonium dichromate. It was the analysis of the behavior of diffraction efficiency parameter through
the intensity diffraction pattern produced by the gratings made with albumin.
Compact reflection holographic recording system with high angle multiplexing
Author(s):
Mayumi Kanayasu;
Takehumi Yamada;
Shunsuke Takekawa;
Kensuke Akieda;
Akiyo Goto;
Manabu Yamamoto
Show Abstract
Holographic memory systems have been widely researched since 1963. However,
the size of the drives required and the deterioration of reconstructed data resulting from
shrinkage of the medium have made practical use of a hologram memory difficult. In light of
this, we propose a novel holographic recording/reconstructing system: a dual-reference beam
reflection system that is smaller than conventional systems such as the off-axis or co-axis
types, and which is expected to increase the number of multiplexing in angle multiplexed
recording. In this multiplex recording system, two laser beams are used as reference beams,
and the recorded data are reconstructed stably, even if there is shrinkage of the recording
medium. In this paper, a reflection holographic memory system is explained in detail. In
addition, the change in angle selectivity resulting from shrinkage of the medium is analyzed
using the laminated film three-dimensional simulation method. As a result, we demonstrate
that a dual-reference beam multiplex recording system is effective in reducing the influence
of medium shrinkage.
Correction method of wavefront aberration on signal quality in holographic memory
Author(s):
Eri Kimura;
Akihito Nakajima;
Kensuke Akieda;
Tomohiro Ohori;
Kiyoto Katakura;
Yo Kondo;
Manabu Yamamoto
Show Abstract
One of the problems that affects the practical use of holographic memory is
deterioration of the reproduced images due to aberration in the optical system. The
medium must be interchangeable, and hence it is necessary to clarify the influence of
aberration in the optical system on the signal quality and perform aberration correction
for drive compatibility. In this study, aberration is introduced in the reference light
beam during image reproduction, and the deterioration of the reproduced image signal
is examined. In addition, for a basic study of aberration correction, the correction
technique using a two-dimensional signal processing is studied.
The electromagnetic wave diffraction from a pyramidal horn antenna in the microwave band
Author(s):
Makoto Ohki;
Koki Sato;
Shogo Kozaki
Show Abstract
In the microwave band, the radiated wave from the pyramidal horn antenna is calculated in the diffracted field
by the Fresnel approximation. In addition, the Fresnel approximation has been introduced into the diffracted
field with half infinite diffraction plane. This phenomenon is examined compared with the experiment value
based on a hologram interpretation.
In this report, the electromagnetic diffracted field with the pyramid horn antenna is calculated as the first
stage under the Fresnel approximation. As a result, the hologram was made by interfering with the reference
wave whose obtained diffracted field and angle of incidence are 60° on the computer. It can be interpreted that
this is one computer generated hologram. Moreover, the image that this hologram pattern is reconstructed in
optics with the He-Ne laser was obtained.
Optimization of half-tone technology for diffractive microlens fabrication
Author(s):
V. P. Korolkov;
R. K. Nasyrov;
A. R. Sametov;
S. A. Suhih
Show Abstract
A new approach for the optimization of diffractive microlenses fabrication is presented. The problem is that fabrication
process brings errors in profile formation. These errors decrease diffractive efficiency and wavefront quality. However,
microlens quality can be increased by optimization of the fabrication process that takes into account transfer functions of
technological equipment. We have applied this method for half-tone technology. Calibration samples were fabricated and
transfer function was experimentally measured. Then initial half-tone mask was corrected and microlenses with higher
quality were produced.
Improvement of camera arrangement in computer-generated holograms synthesized from multi-view images
Author(s):
Noriyuki Hayashi;
Yuji Sakamoto;
Yasuhiro Honda
Show Abstract
Computer-generated hologram (CGH) is a technique that enables recording optical systems for holography by computer simulation, and can reconstruct ideal 3D images.
Since CGH requires the model data of objects, it is necessary for creating 3D images of real existing objects to model them precisely.
However, it is often difficult to obtain this data.
To solve this problem, there has been much research into multi-view projection image based methods that do not require 3D model data.
CGH using integral photography and CGH using multi-view projection obtained by lens array are examples of this research.
However, these methods have some problems.
First, their optical recording systems are complex and expensive, and therefore, realizing these systems is difficult.
Another problem is that enormous projections are required to generate a hologram with sufficient pixel size.
In the past, a method to generate holograms from multi-view images taken with digital cameras was proposed.
Additionally, to generate CGHs using multi-view images from randomly arranged cameras, we proposed a method that uses distance transformations, rotations of light waves, and an algorithm that sets up hologram parameters automatically by using camera arrangement information.
In this paper, the results of numerical reconstructions are compared, and both the motion parallax and resolution of the reconstructed images are discussed.
The proper number of multi-view projections needed will be derived from this discussion.
Fast calculation method for CGHs by using spherical pre-calculated object light
Author(s):
Kohei Hosoyachi;
Yuji Sakamoto
Show Abstract
Holography is a three-dimensional technology. Light waves from an object are recorded and reconstructed
using holograms. Computer generated hologram (CGH) is performed by computer simulation. However,
an enormous amount of computational time is required for calculating CGHs. This paper is focused on
high speed calculation for CGH. There are the two main methods for calculating CGH, such as the point
light method and the method based on Fourier transforms. The point light method calculates light waves
from objects but requires an enormous amount of computation time. The other methods based on Fourier
transforms calculates using a fast Fourier transform algorithm, and the calculation speed is faster than
one of the point light method. However, the calculation for complex objects requires many FFTs, so the
computational time is enormous. To improve the problem, we have proposed a fast calculation method
for computer generated holograms that uses cylindrical pre-calculated object light.9 This method does not
require a FFTs. Cylindrical pre-calculated object light is made by calculating light waves from a basic
object on a semi-circle cylinder. This method calculates the light of arbitrary object shapes by transforming
pre-calculated object light. However, a large amount of memory is required. In this paper, to improve this
method, we reduce this memory requirement by using spherical pre-calculated object light. We achieved a
transfer distance from an object to a hologram by using spherical pre-calculated object light. Moreover, the
computational time of our method is reduced by using graphics processing units.
Consideration of improvement of electro-holographic stereogram
Author(s):
Koki Sato;
Masataka Tozuka;
Makoto Ohki;
Kunihiko Takano
Show Abstract
Computer holographic stereogram (CHS) is useful for holographic 3D TV because it is constructed from
the multi horizontal viewpoint plane images and is compatible to the multi camera stereoscopic image.
Each hologram is recorded as a slit hologram (element hologram) but total viewing area and the number
of the element holograms have been limited to some extent by the size and the resolution points of LCD.
Therefore we used two LCDs for making CHS and deposited them horizontally and increased the viewing
points to two times and extend the display area to satisfy the binocular parallax. We considered how
viewing area becomes extended. We consider how we could improve the characteriostics of the images of
CHS. We got moving images with this system using web-camera and also we considered the real time
calculation about the hologram 3D-TV.
Photoanisotropy in polarization-sensitive medium developed on the basis of polar water-soluble components
Author(s):
Irakli Chaganava;
George Kakauridze;
Barbara Kilosanidze
Show Abstract
In order to obtain a polarization sensitive materials with improved characteristics, there was conducted intensify
interaction between the components of recording media through the interaction between the molecular electrostatic
forces. For creating materials there were used various organic dyes capable of photochemical geometric isomerization
under the influence of actinic polarized light with a wavelength closed to the maximum of the absorption spectrum of
each dye. Various polarization sensitive materials have been synthesized based on the polar water-soluble components.
Substantial improvement photoanisotropic characteristics of these materials are revealed due to previously added
ionizing functional groups in the chromophoric components. It is shown particular exemplary embodiment of synthesis
the materials composed of dyes which communicate with certain polymers via dipole-ionic bonds. The research data of
medium properties on their base have been brought up for the consideration. In the same way photoanisotropic materials
are created on basis of various polar polymer matrixes which separate macromolecules are capable of establishing
dipole-dipole bonds with each other. Thanks to this circumstance a supplementary number of polymer fragments which
cannot afford direct connection with dye molecules are also able to get drawing into the photoanisotropy inducting
processes. It is displayed the influence of such interactions on material kinetics and value of attainable photoanisotropy.
A capability of achievement extremely high values of photoanisotropy is produced on the material samples based on the
dyes with expanded number of ionized substituent.
Holograms with fluorescent benzyl
Author(s):
A. Olivares-Pérez;
S. Toxqui-López;
I. Fuentes-Tapia;
V. Dorantes-Garcia
Show Abstract
Behavior study of the diffraction efficiency parameter from holographic gratings, with fluorescents inks such as benzyls.
We have been able to make holograms with substances such as fluorescence to blue laser to make transmissions
holograms using ammonium dichromate as photo-sensibilizer and polyvinyl alcohol (PVA) as matrix. Ammonium
dichromate inhibit the fluorescence propertied of inks, mixed in a (PVA) matrix, but we show the results of painting
hologram method with fluorescents inks and describe how the diffraction efficiency parameter changes as a function of
ink absorbed by the emulsion recorded with gratings with a He-Cd laser at 442nm and we later were painting with
fluorescent ink, interesting fluorescence characteristic to the hologram.
Computer-generated "alcove" hologram to display floating image with wide viewing angle
Author(s):
Takeshi Yamaguchi;
Hiroyuki Ozawa;
Hiroshi Yoshikawa
Show Abstract
In this paper, we have investigated the floating image display with the computer-generated hologram (CGH).
As the 3D display, to make strong impression on the viewer, the display should reconstruct the floating image from the display plane.
However, there are few reports about the floating image display with the CGH.
Since the required spatial frequency to the display is very high compared with the rear image display, it is difficult to output the CGH which display the floating image.
If the CGH is output by the inadequate device, the viewing area and the image size of the CGH is limited.
Therefore, to reduce the required spatial frequency for the fringe pattern of the CGH, the position of the object is placed at the behind of the hologram plane.
Also, the huge calculation amount of the fringe pattern is a big problem.
In our work, since we developed our output device (named fringe printer) for the fringe pattern, the pixel pitch of the printed fringe pattern achieves to 0.44 μm.
By using the fringe printer, we have obtained the floating image with the CGH.
The output CGH can reconstruct the floating image, but the reconstructed image only has the narrow viewing angle and the small image size.
To make the wide viewing angle floating image display, we investigate to change the CGH shape from the flat type to curved type.
Also, to solve the huge calculation amount, we employ the GPU for parallel calculation to make the computation faster.
New techniques for wave-field rendering of polygon-based high-definition CGHs
Author(s):
Hirohito Nishi;
Kentaro Higashi;
Yasuaki Arima;
Kyoji Matsushima;
Sumio Nakahara
Show Abstract
Four novel techniques are introduced into polygon-based high-definition CGHs (PBHD-CGH) that feature the
true-fine spatial 3D image accompanied with a strong sensation of depth. The first is algorithm for creating
specular surfaces based on Phong reflection model. This is very useful for providing a feel of material to polygonal
surfaces. The second technique is called digitized holography that replaces the entire processes of classical
holography by their digital counterparts. The wave-field of real-existent objects can be optically reconstructed
by the digitized holography. This technique makes it possible to edit the 3D scene of holograms or create mixed
3D scene of the real and virtual objects. Another technique for creating PBHD-CGH of real-existent objects is
also proposed by a CG-like method using a 3D laser scanner that measures the 3D shape of the object. Finally,
a prototype PBHD-CGH is demonstrated for creating landscape scenery. This CGH is intended to reconstruct
a scene as if the viewers see mountain scenery through the window given by the CGH.
Memory size reduction of the novel look-up-table method using symmetry of Fresnel zone plate
Author(s):
Do-Woo Kwon;
Seung-Cheol Kim;
Eun-Soo Kim
Show Abstract
Novel look-up table (N-LUT) method to dramatically reduce the number of pre-calculated interference patterns required
for generation of digital holograms was proposed. In this method, the N-LUT contains only the fringe patterns of the
object points with unity magnitudes located at each center of the depth-dependent image planes of the object. This
principal fringe pattern (PFP) can be regarded as the Fresnel zone pattern (FZP) computed at each depth that has
reflection symmetry in geometry. Therefore, if we have only half of the PFP, we can generate the computer generated
holography (CGH) without the loss of image quality. But the memory size of LUT could be reduced by half.
Hardware implementation of N-LUT method using field programmable gate array technology
Author(s):
Do-woo Kwon;
Seung-Cheol Kim;
Eun-Soo Kim
Show Abstract
Hardware implementation for holographic 3D display application is researched by many researchers. Therefore, in this
paper, we propose the hardware implementation method for novel look-up table (N-LUT) method using Field
Programmable Gate Array (FPGA) technology. In the proposed method, calculation process is divided by some segment
block for fast parallel processing of calculation of N-LUT method. That is, by using parallel processing by use of some
segmented block based on FPGA technology, calculation speed of CGH can be increased