A one-dimensional novel-look-up-table (1-D N-LUT) has been implemented on the graphics processing unit of GTX 690 for the real-time computation of Fresnel hologram patterns of three-dimensional (3-D) objects. For that, three types of optimization techniques have been employed, which include the packing technique of input 3-D object data and the managing techniques of on-chip shared memory and registers. Experimental results show that the average hologram calculation time for one object point of the proposed system has been found to be 0.046 ms, which confirms that the proposed system can generate almost 3 frames of Fresnel holograms with 1920×1080 pixels per second for a 3-D object with 8000 object points.
In this paper, a novel approach for fast generation of video holograms of three-dimensional (3-D) moving objects using compensated principal fringe patterns (C-PFP)-based novel-look-up-table (N-LUT) method is proposed. If the object point is changed between frames, two calculations are needed in conventional temporal redundancy-based N-LUT (TRN- LUT) method, but only one calculation is needed by compensating the difference in intensity and depth values using C-PFP. That is, hologram patterns for moving 3-D object can be calculated by simply multiplying the C-PFP to hologram pattern by difference of depth value. Experimental results with test 3-D video having camera panning reveal that the average number of calculated object points and the average calculation time for one object point of the proposed method, have found to be reduced down to 47.3%, 41.7%, and 40.5%, 32.9%, respectively compared to those of the conventional N-LUT and TR-N-LUT methods.
KEYWORDS: Computer generated holography, Video, Holograms, 3D image processing, Fringe analysis, Video acceleration, 3D displays, Data processing, Video processing, Motion estimation
A new approach for fast generation of computer-generated-holograms (CGHs) by combined use of the N-LUT method and block matching motion compensation technique is proposed. Here, we apply block matching-based motion compensation algorithm to N-LUT-based CGH generation method by which a higher similarity between adjacent frames can be obtained. In the proposed method, the input video images are divided into blocks of fixed size and the CGHs of every block in reference frames are pre-calculated with the N-LUT method. The motion vectors of every block in the reference frame are extracted between reference frame and current frame, and a compensated frame image can be obtained by shifting every block’s position according to the motion vectors. Through this process, 3-D objects data to be calculated for its video holograms are dramatically reduced leading to the greater reduction of the calculation time compared with the conventional temporal redundancy-based N-LUT (TR-N-LUT) method. The experiments have found that the average number of calculated object points for one frame and the average calculation time for one object point of the proposed method are reduced by 30.05% and 21.23% respectively compared to those with the conventional TRNLUT method.
KEYWORDS: Computer generated holography, Video, 3D image processing, Holograms, Image segmentation, Fringe analysis, 3D video compression, Video compression, Holography, 3D displays
Thus far, various approaches to generate the computer-generated holograms (CGHs) of 3-D objects have been suggested
but, most of them have been applied to the still images, not to the video images due to their computational complexity.
Recently, a method to fast compute the CGH patterns of 3-D video images has been proposed by combined use of data
compression and novel look-up table (N-LUT) techniques. In this method, temporally redundant data of 3-D video
images are removed with the differential pulse code modulation (DPCM) algorithm and then the CGH patterns for these
compressed video images are calculated with the N-LUT method. However, as the 3-D objects move rapidly, image
differences between the video frames may increase, which results in a massive growth of calculation time of the video
holograms. Therefore, we propose a novel approach to significantly reduce the computation time of 3-D video holograms
by employing a new concept of motion-vector of the 3-D object. In the proposed method, 3-D objects are firstly
segmented from the 1st frame of the 3-D videos, and the CGH patterns for each segmented object are computed with the
N-LUT algorithm. Secondly, motion vectors between each segmented object and the corresponding objects in the
consecutive 3-D video frames are calculated. Thirdly, the CGH patterns for each segmented object are shifted with the
calculated motion vectors. Finally, all these shifted CGH patterns are added up to generate the hologram patterns of the
consecutive 3-D video frames. To confirm the feasibility of the proposed method, experiments are performed and the
results are comparatively discussed with the conventional methods in terms of the number of object points and
computation time.
In this paper, a new method for efficient generation of video hologram for 3-D video is proposed by combined use of
redundant data of 3-D video and look-up table techniques. That is, temporal redundant data in inter-frame of 3-D video
image is removed using differential pulse code modulation (DPCM) method between frames then inter-line redundant
data in intra-frame of 3-D video image is also removed using DPCM algorithm between lines. Experimental results show
that, in the proposed method, the average number of calculated object points for 3-D objects have been reduced by
23.3% for top-down scanning scheme, compared to the conventional TR_NLUT method. And, the average calculation
time for one object point has been also reduced by 21.0%, compared to the conventional TR_NLUT. Good experimental
results with 3-D test moving pictures finally confirmed the feasibility of the proposed method in fast generation of CGH
patterns for 3-D videos.
In this paper, we propose a new approach for accelerated computation of the computer-generated hologram (CGH) of a
3-D object by using the N×N-point principle fringe patterns (PFPs)-based novel look-up table (N-LUT) method. Using
the two-dimensional (2-D) run-length encoding (RLE) algorithm, redundant data of a 3-D object are extracted in image
blocks and re-grouped into an N×N-point redundancy map depending on the block size. Basing on this redundancy map,
the N×N-point PFPs are calculated, from which the CGH pattern of a 3-D object can be generated. With the block-based
extraction of the redundant data and the N×N-point PFPs-based computation of the CGH pattern, the object points to be
calculated could be significantly reduced, which results in a great increase in the computational speed. Experimental
results show that for 3×3-point PFPs, the computational speed of the proposed method has been improved by 61.16%
compared to the conventional N-LUT method.
We present a new approach for accelerated computation of hologram patterns of a three-dimensional (3-D) image by taking into account of its interline redundant data. Interline redundant data of a 3-D image are extracted with the differential pulse code modulation (DPCM) algorithm, and then the CGH patterns for these compressed line images are generated with the novel lookup table (N-LUT) technique. To confirm the feasibility of the proposed method, experiments with four kinds of 3-D test objects are carried out, and the results are comparatively discussed with the conventional methods in terms of the number of object points and the computation time. Experimental results show that the number of calculated object points and the computation time for one object point have been reduced by 73.3 and 83.9%, on the average, for four test 3-D images in the proposed method employing a top-down scanning method, compared to the conventional method.
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
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.
In general, adjacent pixels of a 3-D image have very similar values of intensity and depth and some of them even have
the exactly same values of them each other. In other words, a 3-D image has a spatial redundancy in intensity and depth
data. This spatial redundancy can be represented with the run-length encoding method, which has been used for data
reduction of the conventional 2-D images. Also, when these redundancies are expanded by line scale, the values of the
line have similar value of the previous line.
Recently, 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 fringe patterns for other object points on each image
plane can be obtained by simply shifting this pre-calculated PFP according to the displaced location values from the
center to those points and adding them together. Accordingly, CGH pattern for arbitrary line is shifted with amount of
discretization step for the direction of next line, same images for arbitrary line are generated in the next line. And then
differences between two lines are occurred, these differences are compensated in CGH pattern using the N-LUT method.
Accordingly, in this paper, a new approach for fast computation of CGH patterns for the 3-D image by taking into
account of the line-redundancy between lines of the 3-D image is proposed. Some experiments with a test 3-D object are
carried out and the results are compared to those of the conventional methods.
Recently, a 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 number of the fringe patterns to
be stored in the LUT can be dramatically reduced by employing a new concept of the principal fringe pattern (PFP). In
this method, the fringe patterns for other object points on each image plane can be obtained by simply shifting this precalculated
PFP according to the displaced location values from the center to those points and adding them together.
Fringe patterns for all object points located on each image plane can be generated by adding the shifted versions of the
PFP. Therefore, the final CGH pattern for an object volume can be obtained by overlapping all PFPs generated on each
depth-dependent image plane. Therefore, the size of LUT is determined by the amount of shift of the PFP. But, if the
resolution of object is increased, the size of PFP is increased. Thus the size of LUT is increased. And also, if the pixel
pitch of hologram is decreased, the amount of shift is increased. Thus the size of LUT is also increased. Therefore, in this
paper, we propose the memory reduction method using the relation of pixel pitch of hologram and reconstruction
distance. That is, size of PFP is reduced by controlling of the distance of object and pixel pitch while maintaining the
quality of the video. Some experiments with a test 3-D object are carried out and the reduction ratio of LUT is analyzed.
American Sign Language (ASL) is one of the languages giving the greatest help for communication of the hearing
impaired person. Current 2-D broadcasting, 2-D movies are used the ASL to give some information, help understand the
situation of the scene and translate the foreign language. These ASL will not be disappeared in future three-dimensional
(3-D) broadcasting or 3-D movies because the usefulness of the ASL. On the other hands, some approaches for
generation of CGH patterns have been suggested like the ray-tracing method and look-up table (LUT) method. However,
these methods have some drawbacks that needs much time or needs huge memory size for look-up table. Recently, a
novel LUT (N-LUT) method for fast generation of CGH patterns of 3-D objects with a dramatically reduced LUT
without the loss of computational speed was proposed. Therefore, we proposed the method to efficiently generate the
holographic ASL in holographic 3DTV or 3-D movies using look-up table method. The proposed method is largely
consisted of five steps: construction of the LUT for each ASL images, extraction of characters in scripts or situation, call
the fringe patterns for characters in the LUT for each ASL, composition of hologram pattern for 3-D video and hologram
pattern for ASL and reconstruct the holographic 3D video with ASL. Some simulation results confirmed the feasibility of
the proposed method in efficient generation of CGH patterns for ASL.
KEYWORDS: Computer generated holography, 3D image processing, Fringe analysis, Holograms, 3D displays, Digital holography, 3D image reconstruction, Holography, Diffraction, 3D modeling
Recently, 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 fringe patterns for other object points on each image
plane can be obtained by simply shifting this pre-calculated PFP according to the displaced location values from the
center to those points and adding them together. Accordingly, CGH pattern for arbitrary line is shifted with amount of
discretization step for the direction of next line, same images for arbitrary line are generated in the next line. And then
differences between two lines are occurred, these differences are compensated in CGH pattern using the N-LUT method.
Accordingly, in this paper, a new approach for fast computation of CGH patterns for the 3-D image by taking into
account of the line-redundancy between lines of the 3-D image is proposed. Some experiments with a test 3-D object are
carried out and the results are compared to those of the conventional methods.
Accordingly, in this paper, a new approach for fast computation of CGH patterns for the 3-D image by taking into
account of the line-redundancy between lines of the 3-D image is proposed. Some experiments with a test 3-D object are
carried out and the results are compared to those of the conventional methods.
KEYWORDS: 3D acquisition, 3D image processing, 3D image reconstruction, Target recognition, Reconstruction algorithms, Image processing, Integral imaging, Detection and tracking algorithms, 3D modeling, 3D displays
Recently, many research works are actively being done on three-dimensional (3-D) recognition using correlation method
throughout the world. To recognize the 3-D object from the target image, the reference image is needed. That is, target
image is captured using lenslet array as a form of elemental image array (EIA) by integral imaging method. Then, the
EIA is reconstructed at each depth plane as a form of plane object image (POI) using computational integral imaging
reconstruction method. Then, the correlation process is performed at all POIs with reference image. In general, twodimensional
image that is the scene from the front view of the object is used as a reference image. Thus if target has big
depth range, the reconstructed POIs are not clear at all depth range because some part is focused whereas the other ones
are blurred. Therefore, there are no POIs having clear 3-D object. In other words, it is not able to find the accurate
location of 3-D object if 2-D image is used as a reference image. Accordingly, in this paper a new method to find the
accurate location of 3-D object by using 3-D reference images that is captured by integral imaging method is proposed.
That is, the correlation process is performed the reconstructed POIs of target image and reconstructed POIs of reference
image at all depth range. To confirm the proposed method, 'car' is used as a 3-D object. From this simulation results
confirmed the feasibility of the proposed method to extract the location of 3-D object.
News ticker is used to show breaking news or news headlines in conventional 2-D broadcasting system. For the case of
the breaking news, the fast creation is need, because the information should be sent quickly. In addition, if holographic 3-
D broadcasting system is started in the future, news ticker will remain.
On the other hands, some approaches for generation of CGH patterns have been suggested like the ray-tracing method
and look-up table (LUT) method. However, these methods have some drawbacks that needs much time or needs huge
memory size for look-up table. Recently, a novel LUT (N-LUT) method for fast generation of CGH patterns of 3-D
objects with a dramatically reduced LUT without the loss of computational speed was proposed. Therefore, we proposed
the method to efficiently generate the holographic news ticker in holographic 3DTV or 3-D movies using N-LUT method.
The proposed method is largely consisted of five steps: construction of the LUT for each character, extraction of
characters in news ticker, generation and shift of the CGH pattern for news ticker using the LUT for each character,
composition of hologram pattern for 3-D video and hologram pattern for news ticker and reconstruct the holographic 3D
video with news ticker.
To confirm the proposed method, moving car in front of the castle is used as a 3D video and the words 'HOLOGRAM
CAPTION GENERATOR' is used as a news ticker. From this simulation results confirmed the feasibility of the proposed
method in fast generation of CGH patterns for holographic captions.
A liquid crystal panel for a video projector is often used for holographic television. However, its pixel size and pixel number are not enough for practical holographic 3-D display. Therefore, a multipanel configuration is generally used to increase the viewing window and displayed image size, and many spatial light modulators should be used in them. We propose a novel method to increase the viewing window of a holographic display system. The proposed method, which is implemented by using a mirror module and 4-f lens set, is to reconfigure the beam shape reflected by a spatial light modulator. The equipment is applied to a holographic display system, which has only a single spatial light modulator; a hologram could be displayed in a wider viewing window by the equipment than that of the conventional method. By the proposed method, the resolution of the reconfigured spatial light modulator has double resolution in the horizontal direction. Inversely, the vertical resolution is decreased. Even if the vertical resolution is decreased, a viewer could get 3-D effect because humans get more 3-D information in the horizontal direction. We have experimented using a liquid crystal on silicon (LcOS), whose resolution is 4096×2160 pixels. The reconfigured resolution by the mirror module is 8192×1080 pixels. From the experiments, the horizontal viewing window is almost two times wider than that without the mirror module. As a result, the hologram can be observed binocularly.
KEYWORDS: 3D image processing, Video, 3D video compression, Computer generated holography, Video compression, Holograms, Image compression, 3D displays, Holography, Fringe analysis
In this paper, a new method for efficient generation of video hologram for 3-D video is proposed by combined use of
redundant data of 3-D video and look-up table techniques. That is,
3-D video is a collection of sequential 3-D images
having depth data as well as intensity and neighboring moving pictures in the 3-D video differ slightly from each other.
Therefore, a method for fast computation of CGH patterns for 3-D video images is proposed by combined use of
temporal redundancy and look-up table techniques. Further more, adjacent pixels of a 3-D image have very similar
values of intensity and depth and some of them even have the exactly same values of them each other. In other words, a
3-D image has a spatial redundancy in intensity and depth data. Therefore, a method for fast computation of CGH
patterns for the 3-D image by taking into account of the spatial redundancy of the 3-D image is proposed. To confirm the
feasibility of the proposed method, some experiments with a 3-D test object are carried out and the results are compared
to those of the conventional methods in terms of a computational speed and a required memory size.
KEYWORDS: Video, Video coding, 3D displays, Video processing, Computer programming, 3D image processing, Motion estimation, Cameras, Displays, 3D video compression
In this paper, variable disparity-motion estimation (VDME) based
3-view video coding is proposed. In the encoding,
key-frame coding (KFC) based motion estimation and variable disparity estimation (VDE) for effectively fast three-view
video encoding are processed. These proposed algorithms enhance the performance of 3-D video encoding/decoding
system in terms of accuracy of disparity estimation and computational overhead. From some experiments, stereo
sequences of 'Pot Plant' and 'IVO', it is shown that the proposed algorithm's PSNRs is 37.66 and 40.55 dB, and the
processing time is 0.139 and 0.124 sec/frame, respectively.
In this paper, we propose a new approach for fast generation of computer-generated holograms (CGHs) of a 3-D object
by using the run-length encoding (RLE) and the novel look-up table (N-LUT) methods. With the RLE method spatially
redundant data of a 3-D object are extracted and re-grouped into the N-point redundancy map according to the number of
the adjacent object points having the same 3-D value. Then, basing on this redundancy map N-point principle fringe
patterns (PFPs) are newly calculated by using the 1-point PFP of the N-LUT (novel look-up table) and the CGH pattern
for the 3-D object is generated with these N-point PFPs. In this approach, object points to be involved in calculation of
the CGH pattern can be dramatically reduced and as a result an increase of computational speed can be obtained. Some
experiments with a test 3-D object are carried out and the results are compared to those of the conventional methods.
A novel approach for discrimination of partially occluded 3-D target objects from reconstructed digital hologram by
using a spatial filtering scheme is proposed. Because of the distance condition among the target and occluding objects in
the digital hologram system, the occluding objects would directly act as some noises to the reconstructed target image as
a result performance of the digital hologram based 3-D target recognition system might be severely deteriorated. When
we just focuse on the occluded image for recognition, sometimes we do not know the shape exactly. But if we extract the
occluding objects from the hologram pattern, it is recognized more clearly when we reconstructed. Because of the
property of hologram, some pixel does not have information what we want and other pixels have it. In accordance with it,
we are able to discriminate the shape of occluded object even though the part of occluded object is not brightly and
clearly. In this paper, by selectively subtraction the occluding object noises from the recorded hologram pattern using a
spatial filtering scheme, robust discrimination of 3-D targets from the occluding objects can be realized with this spatial
filtered hologram. Thus, performance of the proposed digital hologram based 3-D target recognition system can be
dramatically improved. In order to show the feasibility of the proposed method, some experiments with test objects are
carried out and the results are presented.
KEYWORDS: Computer generated holography, 3D image reconstruction, Fringe analysis, 3D image processing, Holograms, Near field diffraction, 3D displays, Digital holography, Holography, Image processing
Even though many kinds of approaches to generate CGH patterns of the 3D object image were suggested, but most of them could be applied to single-color 3D objects, so that we still need some possible approach for implementation of full-color holograms for the 3D images. In this paper, a method to reduce the size of required N-LUTs for generating of a full-color CGH patterns using a relation of distance and wavelength in Fresnel diffraction is proposed. In addition, some
simulations with test images are carried out, and finally the feasibility of the proposed method was confirmed.
In this paper, we propose the holographic reconstruction by overlapped pattern from the images that captured by Integral
Image (II) method with some image processing. An elemental image array of 3D object is pick-upped by II method and
modified to a sub-image array. Then each elemental hologram pattern is generated by each sub-image with
computational technique then overlapped like uniform ratio. Finally, the overlapped hologram pattern is reconstructed
using the reference wave which is used to the hologram generation process. In this simulation, the characters of 'KW'
with different depth are used as 3D objects and pick-upped and processed using II method. Then processed image is
successfully reconstructed using hologram technique.
KEYWORDS: Computer generated holography, Video, Holograms, Fringe analysis, 3D image reconstruction, 3D image processing, Digital holography, Image processing, Video processing, 3D displays
Even though many kinds of approaches to generate CGH patterns of the 3D object image were suggested, but most of
them could be applied to static 3D objects, so that we still need some possible approach for implementation of digital
video holograms for the 3D moving pictures. In this paper, a new approach for fast computation of CGH patterns for 3D
video images using the N-LUT by taking into account of temporal redundancy of 3D moving pictures is proposed. In
addition, some simulations with test video images are carried out and the results are compared with those of the
conventional methods. Finally the feasibility of the proposed method was confirmed.
KEYWORDS: Computer generated holography, Video, Fringe analysis, Holograms, 3D image processing, Video processing, Image processing, 3D image reconstruction, 3D displays, Video compression
The traditional method to generate CGH patterns takes up many times thus it is difficult to implement the actual use. To
improve the computation speed, the pre-computed look-up table containing all possible elemental fringes is proposed.
But to generate CGH for many frames of video images, LUT method also takes up many times, because elemental fringe
patterns for entire points of each frame are summated. In the ordinary video images, when a frame is converted to next
frame, the case that the whole picture be changed is rare. That is, video images have much redundancy between adjacent
frames. In this paper, an efficient generation method of hologram pattern for video images using general property of
video images and principle of LUT method is proposed.
KEYWORDS: Holograms, 3D image processing, 3D image reconstruction, Image processing, Imaging arrays, Integral imaging, 3D displays, Digital holography, Holography, Computer generated holography
In this paper, we approach the holographic reconstruction method from the images that pick-upped by Integral Imaging (II) technique with some image processing. An elemental image array of 3D object is captured by II technique and transformed to a sub-image array. Then each elemental hologram pattern is generated using each sub-image by computational method and arranged like a form of sub-image array. And then, the arranged hologram pattern is reconstructed using the reference wave which is using the hologram generation process. In the simulation, the characters of '3D' with different depth are used as 3D objects and pick-uped and processed using II technique. Then processed image is successfully reconstructed using hologram technique.
In this paper, we propose the holographic reconstruction technique from the images that captured by II technique with
some image processing. Elemental image array of 3D object is captured by II technique and transformed by sub-image
array. Then elemental hologram pattern is generated by each sub-image by computational method then arranged by form
of sub-image array. Finally, the arranged hologram pattern is reconstructed using the reference wave that using the
hologram generation process. In the simulation, the characters of 'KW' with different depth are used as 3D objects and
pickuped and processed using II technique. Then processed image is successfully reconstructed using hologram
technique.
KEYWORDS: 3D image processing, 3D image reconstruction, 3D displays, Integral imaging, Image processing, 3D modeling, Ray tracing, Imaging systems, Optical properties, RGB color model
Recently, integral imaging in various applications has been studied on computerized analyzing techniques for
reconstruction of the three-dimensional objects and display system design. However, conventional reconstruction
technique based on computational integral imaging have some limitations in analyzing information of reconstruction and
designing practical display systems. Because it has primarily been used to analyzing technique based on image
processing through virtual pinhole and simple geometry excluded realistic optical properties. In this paper, we proposed
the novel reconstruction technique using the micro-lens array designed and ray tracing including realistic environments
and optical components in practical integral imaging system. As a theoretical background, the principle of the proposed
method is described. To analyze the reconstruction system model, rays are traced by using the LightTools software. As a
result, a 3-D image reconstructed by integrated rays in designed model is illustrated and some experimental results and
system analysis are also presented as well.
Several approaches for increasing the speed and simplicity in computation of the digital holograms of the 3-D object
have been presented with applications to real-time display of holographic images. So far, a look-up table (LUT) approach
in which the pre-calculated elemental interference patterns for all possible points of the object are provided, has gained a
lot of speed increase. But the greatest drawback of this method is the enormous size of the LUT. In this paper, a novel
LUT method to dramatically reduce the number of pre-calculated elemental interference patterns required for
computation of digital holograms compared with that of the conventional approach is proposed. Some experimental
results finally reveal that the computation speed and the required memory size of the proposed LUT approach are found
to be 48.8 times faster than that of the ray-tracing method and 217 times smaller than that of the conventional LUT
method, respectively.
KEYWORDS: Medium wave, Holograms, 3D image reconstruction, Image segmentation, Holography, 3D image processing, Computer generated holography, 3D displays, Imaging arrays, Integral imaging
In this paper, we propose the II reconstruction technique from the hologram pattern with some image processing. That is,
with II reconstruction, we can simplify the reconstruction process by eliminating the coherent light source, which is used
in the conventional display holographic system. That is, computer generated holography is used as a holographic 3D
image capturing. Then generated hologram pattern is segmented and reconstructed respectively. In holographic recording
process, object point is recorded all over the region of hologram pattern. In other words, object point is recorded at
hologram pattern at each perspective viewpoint. Therefore, when the segmented hologram pattern is reconstructed,
perspective images are reconstructed. That is, multi-view images with horizontal and vertical parallax are reconstructed.
These multi-view images has a full parallax are similar to sub-image array in II. Therefore, all reconstructed images are
rearranged by form of sub-image array, and transformed by elemental image array. Then the elemental images are
reconstructed by II technique. In the experiment, the characters of 'KW' with different depth are used as 3D objects.
Then, CGH pattern of 2,000 × 2,000 pixels is generated with input and depth images, and the CGH pattern is segmented
and reconstructed respectively. And the reconstructed holographic images are integrated as a sub-image array then
successfully reconstructed using II technique.
Stereo matching, a technique for acquiring depth information from many images obtained by several cameras, was developed several decades ago. Recently a technique that use a lens array instead of several cameras have regarded as one of a novel depth-extraction technique because of the advantages offered by its simple system configuration. In this paper, a novel method using integral imaging (II) technique to generate the computer-generated hologram (CGH) patterns of a real three-dimensional (3D) object is proposed. Elemental images of a real 3D object are captured by an II pick up system and the captured images are modified. Disparity maps are estimated from the modified images. Then, depth data for each pixel of the object can be extracted on the frame basis from these estimated maps. Using these depth data and original color images, hologram patterns of a real object can be computationally generated. In the experiment, the character 'K' and 'W' were used as a real 3D object. Elemental images of 'K' and 'W' are captured by using the digital camera and micro lens array. And its depth data are extracted from them. Then, CGH patterns are generated with these depth-annotated images of 'K' and 'W'. Finally, the patterns are experimentally displayed via a holographic display system.
In this paper, a new 3D adapter system with a lens unit interposed between a capturing lens and an adapter housing for alternately passing right and left video images of an object there through, wherein the lens unit has an entrance pupil point formed outside the lens unit, the lens unit has a magnification of 1:1, and the lens unit comprises a plurality of symmetrically arranged lenses for reversing the video images, whereby it is possible to capture video images with wide picture angles without increasing the size of the adapter housing, and to prevent occurrence of any distortion in the resulting video images comprised of the integrated right an left images of the object.
From some experimental result, the conventional 3D adapter system has the standard deviation of x axis is 3.92 pixels and the standard deviation of y axis is 2.92 pixels. But in the used camera system, the standard deviation of x axis is 1.11 pixels and the standard deviation of y axis is 0.39 pixels. Thus the errors in pixel of proposed system are smaller than the conventional system.
In this paper, a new LCD polarized stereoscopic projection method with improved light efficiency is suggested. In the proposed system, two external polarizers are taken away from the conventional LCD polarized stereoscopic projection system by effectively taking into account of inherent polarization properties of the LCD projectors, so that light efficiency of the proposed system can be dramatically improved. From some experimental results with the Type-1 LCD projectors of NEC MT 1060R, it is found that the proposed system shows zero light loss in the polarization process and the resultant stereoscopic image projected from this system is 213%, 75% and 300% brighter than those projected from the conventional Type-1 LCD projector-based, Type-2 LCD projector-based and Type-3 projector-based systems, respectively.
In this paper, a bi-directional stereo matching algorithm based-on adaptive matching window is proposed. That is, by adaptively predicting the mutual correlation between stereo images pair using the proposed algorithm, the bandwidth of stereo input images pair can be compressed to the level of a conventional 2D image and a predicted image also can be effectively reconstructed using a reference image and disparity vectors. Especially, in the proposed algorithm, first feature values are extracted from input stereo images pair. Then, a matching window for stereo matching is adaptively selected depending on the magnitude of these feature values. That is, for the region having larger feature values, a smaller matching window is selected while, for the opposite case, a larger matching window is selected by comparing predetermined threshold values. This approach is not only able to reduce a mismatching of disparity vectors which occurs in the conventional dense disparity estimation with a small matching window, but is also able to reduce blocking effects which occur in the coarse disparity estimation with a large matching window. In addition, from some experiments using stereo sequences of 'Man' and 'Fichier', it is shown that the proposed algorithm improves the PSNRs of a reconstructed image to about 6.78 dB on average at ± 30 search ranges by comparing with that of conventional algorithms. And also, it is found that there is almost no difference between an original image and a reconstructed image through the proposed algorithm by comparison to that of conventional algorithms.
KEYWORDS: Cameras, Distortion, Calibration, 3D displays, Imaging systems, 3D image processing, Signal processing, 3D acquisition, Image processing, Charge-coupled devices
In this paper, we proposed multiview calibration system for an effective 3D display. This system can obtain 4-view image from multiview camera system. Also it can be rectify lens and camera distortion, an error of bright and color, and it can be calibrate distortion of geometry. We proposed the signal processing skill to calibrate the camera distortions which are able to take place from the acquired multiview images. The discordance of the brightness and the colors are calibrated the color transform by extracting the feature point, correspondence point. In addition, the difference of brightness is calibrated by using the differential map of brightness from each camera image. A spherical lens distortion is corrected by extracting the pattern of the multiview camera images. Finally the camera error and size among the multiview cameras is calibrated by removing the distortion. Accordingly, this proposed rectification & calibration system enable to effective 3D display and acquire natural multiview 3D image.
In this paper, new configuration of inner optic module of LCD projectors for polarized stereoscopic projection with no light loss in the process of polarization is proposed. In the proposed system, two polarizing filters or waveplates, which have been employed in the conventional LCD polarized stereoscopic projection systems and consequently caused an additional light loss and image distortion, are excluded by modifying the inner optic module of LCD projectors and some steps of image processing, so that maximum light efficiency in the polarization process can be obtained from the proposed method.
In this paper, a novel method to generate computer-generated holograms(CGH) of a real three-dimensional(3D) object using stereoscopic video images is proposed. Stereoscopic video images of a real 3D object are captured with a 3D camera system and disparity maps between the left and right image pairs are estimated on the frame basis. Then, depth data for each pixel of the object can be extracted from these estimated disparity maps. Using these depth data and original color images, hologram patterns of a real object can be computationally generated. In the experiment with a 3D adaptor(3D58 LenSys, Wasol) system, stereoscopic images of a real 3D object of 'cup' are captured and its depth data are extracted from them. Then, CGH patterns are generated with these depth-annotated images of the 'cup' and experimentally displayed via a holographic display system.
In general, most conventional three-dimensional moving image capturing device uses two cameras for capturing the right and left video signals of an object. But this system has many disadvantages in that it essentially requires two cameras each having various accessories, and in that it is difficult and takes much time to integrate the moving images. Also, some calibration and rectification processes must be needed in the practical applications, because the operational characteristics of these two cameras can't be made to be same. On the other hand various camcorder adapters for capturing 3D moving image have been developed in order to eliminate the disadvantages of this two-camera system. But in this system, an entrance pupil point is formed inside the 3D moving image capturing device, so that when a wide moving image having a wider picture angle is to be captured, it is necessary to greatly increase the sizes of the total reflecting mirrors, which causes the adapter housing having the total reflecting mirrors mounted therein to be increased in size. Accordingly, in this paper, a new compact electro-optical 3D camcorder adapter for effectively capturing three-dimensional image having any picture angles is proposed and its performance is analyzed by comparing with those of the conventional ones. Some experimental results also confirm the superiority of the proposed system and its usefulness in the practical applications.
In this paper, a new color LCoS(liquid crystal on silicon)-based holographic full-color 3D display system is proposed. As the color LCoS SLM can produce a full-color image pattern using a color wheel, only one LCoS panel is required in this approach for full-color reconstruction of a 3D object. In the proposed method, each color fringe-pattern is generated and tinted with each color beam. R, G, B fringe-patterns are mixed up and displayed on the color LCoS SLM. And then, Red fringe-pattern can be diffracted at the red status of a color wheel and at the same manner Green/ Blue fringe-patterns can be diffracted at the green/ blue status of a color wheel, so that a full-color electro-holographic 3D image can be easily reconstructed by using some simple optics. From some experiments, a possibility of implementation of a new compact LCoS-based holographic full-color 3D video display system is suggested.
KEYWORDS: 3D image reconstruction, Holography, Holograms, Liquid crystal on silicon, Spatial light modulators, 3D displays, 3D image processing, Video, Computer generated holography, RGB color model
In this paper, a new color LCoS (liquid crystal on silicon)-based holographic full-color 3D display system is proposed. As the color LCoS SLM (spatial light modulator) can produce a full-color image pattern using a color wheel, only one LCoS panel is required for full-color reconstruction of a 3D object contrary to the conventional three-panel method. That is, in the proposed method, each color fringe-pattern is generated and tinted with each color beam. R, G, B fringe-patterns are mixed up and displayed on the color LCoS SLM. And then, the red, green and blue fringe patterns can be diffracted at the corresponding status of a color wheel, so that a full-color holographic image could be easily reconstructed with simple optics. From some experiments, a possibility of implementation of a new LCoS-based holographic full-color 3D video display system is suggested.
In this paper, a new LCD polarized stereoscopic projection method with improved light efficiency is suggested. In the proposed system, two external polarizers are taken away from the conventional LCD polarized stereoscopic projection system by effectively taking into account of inherent polarization properties of the LCD projectors, so that light efficiency of the proposed system can be dramatically improved. From some experimental results with the Type-1 LCD projectors of NEC MT 1060R, it is found that the proposed system shows zero light loss in the polarization process and the resultant stereoscopic image projected from this system is 213%, 75% and 300% brighter than those projected from the conventional Type-1 LCD projector-based, Type-2 LCD projector-based and Type-3 projector-based systems, respectively.
In this paper, as an approach for a wide 3D real image display system without special glasses, a 100" Fresnel lens-based 3D real-projection display system is implemented and its physical size is designed by 2800x2800x1600 mm3 in length, width and depth, respectively. In this display system, the conventional 2D video image is projected into the air through some projection optics and a pair of Fresnel lens and as a result, it can form a floating video image having a real depth. From some experiments with the test video images, the floated 3D video images with some depth have been realistically viewed, in which forward depth of the floated 3D image from the display screen is found to be 35~47 inches and the viewing angle to be 60 degrees, respectively. This feasibility test for the prototype of 100" Fresnel lens-based 3D real image rear-projection display systems suggests a possibility of its practical applications to the 3D advertisements, 3D animations, 3D games and so on.
In this paper, a new stereoscopic 3D imaging communication system for real-time teleconferencing application is implemented by using IEEE 1394 digital cameras, Intel Xeon server computer system and Microsoft’s DirectShow programming library and its performance is analyzed in terms of image-grabbing frame rate. In the proposed system, two-view images are captured by using two digital cameras and processed in the Intel Xeon server computer system. And then, disparity data is extracted from them and transmitted to the client system with the left image through an information network and in the recipient two-view images are reconstructed and displayed on the stereoscopic 3D display system. The program for controlling the overall system is developed using the Microsoft DirectShow SDK. From some experimental results, it is found that the proposed system can display stereoscopic images in real-time with a full-color of 16 bits and a frame rate of 15fps.
In this paper, a new software-oriented autostereoscopic 4-view imaging & display system for web-based 3D image communication is implemented by using 4 digital cameras, Intel Xeon server computer system, graphic card having four outputs, projection-type 4-view 3D display system and Microsoft' DirectShow programming library. And its performance is also analyzed in terms of image-grabbing frame rates, displayed image resolution, possible color depth and number of views. From some experimental results, it is found that the proposed system can display 4-view VGA images with a full color of 16bits and a frame rate of 15fps in real-time. But the image resolution, color depth, frame rate and number of views are mutually interrelated and can be easily controlled in the proposed system by using the developed software program so that, a lot of flexibility in design and implementation of the proposed multiview 3D imaging and display system are expected in the practical application of web-based 3D image communication.
In this paper, a real-time incoherent 3D imaging and display system using the modified triangular interferometer is optically implemented. The incoherent holographic system based-on this modified triangular interferometer employs the superposition of Fresnel zone patterns, in which the respective positions and intensities of the 3D object points are uniquely encoded and from this system the complex holograms without bias and conjugate images for the 3D object can be obtained. In addition, the real and imaginary parts of a complex hologram are obtained by subtracting and adding two hologram patterns. Then, illuminating them coherently and recombining the light passing through the transparencies by the use of the beam splitter allows the complex addition to be performed. Then, the desired 3D image is reconstructed through Fresnel diffraction. From some experiments with a 3D object of “dies”, it is found that the incoherent 3D imaging and display system without the bias and conjugate image can be optically implemented in real-time by using a modified triangular interferometer.
In this paper, a new projection-type autostereoscopic multiview 3D display system for real-time applications is proposed by using IEEE 1394 digital cameras, Intel Xeon server computer system, projection-type 3D display system and Microsoft' DirectShow programming library and its performance is analyzed in terms of image-grabbing frame rate, displayed image resolution, possible color depth and number of views. In the proposed system, four-view color images are initially captured by using four IEEE 1394 digital cameras and then, these are processed in the Intel Xeon server computer system and they are transmitted to the graphic card having 4 output ports for supporting 4-view stereoscopic display system in real-time. These outputs are finally projected to the specially designed-Fresnel screen through four projectors to make 4-view autostereoscopic image. Also, the overall system control program is developed basing on the Microsoft's DirectShow programming library. From some experimental results, it is found that the proposed system can display four-view VGA images with a full color of 16bits and a frame rate of 15fps in real-time.
In this paper, an incoherent holographic 3D imaging and display system usinga modified triangular interferometer is implemented and demonstrated. The incoherent holographic system based-on this modified triangular interferometer employs the superposition of Fresnel zone patterns in which the positions and intensities of the object points are uniquely encoded and from this system the complex holograms without bias and conjugate image for 3D object can be obtained. That is, the light reflected from a 3D object is divided into two beams by a beam splitter and input to the modified triangular interferometer. All patterns of two optical wave that travel the modified triangular interferometer in the clockwise and counterclockwise directions is detected by the CCD camera. Here, four pairs of interference pattern are detected by controlling combination of the waveplates in the modified interferometer system then, a complex hologram pattern without bias and conjugated image can be obtained through the modification process of these four patterns. The Mach-Zehnder interferometer is also employed, in this paper, to reconstruct this complex hologram. The real and imaginary parts of the complex hologram are placed in the upper and the lower arms of the interferometer. The Mach Zehnder intrferometer is used to reconstruct the comeplx hologram. That is, the real and imaginayr parts of a complex hologram are placed in each arm of the interferometer, respectively. And illuminating them coherently and recombining the light passed throught eh transparenceis bytheuse of the beam splitter allows the complex addition to be performed. Then, the desired 3D image is reconstructed through Fresnel diffraction, in which the panel plays a role of a holographic optical element. From some experiments with 3D object of "dies", it is suggested that a practical incoherent holographic 3D imaging and display system using a modifeid triangular interferometer can be implemented, in which the bias and conjugate image problems are alleviated.
In this paper, a photopolymer-based VHOE is optimally manufactured and using this VHOE, an experimental model of the VHOE-based 8-view stereoscopic display system is implemented. That is, the VHOE is optically made by angle-multiplexed recording of 8-view's diffraction gratings in the Dupont's photopolymer(HRF-150-100) using an optimized exposure-time scheduling scheme and then, the VHOE-based 8-view stereoscopic display system is implemented, in which the incident angles of the diffracted reference beams of the VHOE are sequentially synchronized with the respective 8-view stereo images displayed on the LCD panel. From some experimental results using 8-view test images, it is found that 8-view stereo images can be diffracted to the eight different directions corresponding to the incident angles of the reference beams and there is some disparity between the stereo images. From these experimental results, a possibility of implementing the VHOE-based multi-view stereoscopic 3D display system is also suggested.
Recently, the VHOE(volume holographic optical element) is proposed as an optical directional modulator for the time-sequential multiview autostereoscopic 3D display system. In this paper, the exposure-time schedule of the photopolymer for implementing the optimized VHOE(volume holographic optical element) is analyzed. The recording property of the photopolymer is characterized by the function of the cumulative grating strength, which is a function of exposure energy. The cumulative grating strength dependence on the exposure energy are mathematically modeled by using the fourth-order polynomial function. Using this model, the exposure schedule of the photopolymer for recording the given multiple gratings has been calculated. This procedure is repeated until the exposure-time schedule is reached to the best condition. From some experimental results, a possible of implementing the optimized VHOE device by using the proposed exposure-time schedule is suggested.
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