KEYWORDS: 3D displays, Microscopy, 3D image processing, In vivo imaging, Fourier transforms, Image resolution, Video, Video acceleration, Charge-coupled devices, Computer simulations
Here, we present dual-dimensional microscopy that captures both two-dimensional (2-D) and light-field images of an in-vivo sample simultaneously, synthesizes an upsampled light-field image in real time, and visualizes it with a computational light-field display system in real time. Compared with conventional light-field microscopy, the additional 2-D image greatly enhances the lateral resolution at the native object plane up to the diffraction limit and compensates for the image degradation at the native object plane. The whole process from capturing to displaying is done in real time with the parallel computation algorithm, which enables the observation of the sample’s three-dimensional (3-D) movement and direct interaction with the in-vivo sample. We demonstrate a real-time 3-D interactive experiment with Caenorhabditis elegans.
Holography is defined as a two-steps process of capture and reconstruction of the light wavefront scattered from three-dimensional (3D) objects. Capture of the wavefront is possible due to encoding of both amplitude and phase in the hologram as a result of interference of the light beam coming from the object and mutually coherent reference beam. Three-dimensional imaging provided by holography motivates development of digital holographic imaging methods based on computer generation of holograms as a holographic display or a holographic printer. The holographic printing technique relies on combining digital 3D object representation and encoding of the holographic data with recording of analog white light viewable reflection holograms. The paper considers 3D contents generation for a holographic stereogram printer and a wavefront printer as a means of analogue recording of specific artifacts which are complicated objects with regards to conventional analog holography restrictions.
Development of display and its related technologies provides immersive visual experience with head-mounted-display
(HMD). However, most available HMDs provide 3D perception only by stereopsis, lack of accommodation depth cues.
Recently, holographic HMD (HHMD) arises as one viable option to resolve this problem because hologram is known to
provide full set of depth cues including accommodation. Moreover, by virtue of increasing computational power,
hologram synthesis from 3D object represented by point cloud can be calculated in real time even with rigorous
Rayleigh-Sommerfeld diffraction formula. However, in HMD, rapid gaze change of the user requires much faster refresh
rate, which means that much faster hologram synthesis is indispensable in HHMD. Because the visual acuity falls off in
the visual periphery, we propose here to accelerate synthesizing hologram by differentiating density of point cloud
projected on the screen. We classify the screen into multiple layers which are concentric circles with different radii,
where the center is aligned with gaze of user. Layer with smaller radius is closer to the region of interest, hence, assigned
with higher density of point cloud. Because the computation time is directly related to the number of points in point
cloud, we can accelerate synthesizing hologram by lowering density of point cloud in the visual periphery. Cognitive
study reveals that user cannot discriminate those degradation in the visual periphery if the parameters are properly
designed. Prototype HHMD system will be provided for verifying the feasibility of our method, and detailed design
scheme will be discussed.
We propose a one-shot dual-dimension microscope which captures 2D/3D information simultaneously based on light field microscopy. By locating a beam splitter into a relayed light field microscopy system, the simultaneous capture of both 2D and 3D information is possible. Two digital cameras are synchronized and simultaneously capture 2D and 3D information, respectively. We also discuss about the way to present 2D and 3D information together efficiently, and the way to develop the 3D depth image quality with the high resolution 2D image information.
A three-dimensional display using persistence of vision (POV) has its own benefits for natural image expression. Conventional POV display using light emitting diode (LED) array was connected with a high speed motor, so it could be possible to express curved-type two-dimensional display or volumetric three-dimensional display. However, it is necessary to consider interactive three-dimensional display. For example, this kind of volumetric display is hardly applied on interactive display since light emitting parts are placed in the center of a rotating screen. To provide a complementary effort to this need, we propose here a hologram-like interactive volumetric display using LED array type persistence of vision and a pair of parabolic mirrors. We build the volumetric POV display by using small size LED arrays. This POV display is located below a pair of parabolic mirrors so the mirrors make hologram-like volumetric POV images to be reimaged such as 4f system of lenses. Several preliminary experiments will be provided for our proposed method.
Accommodation response of super-multiview display device, which is implemented to provide horizontal-only parallax,
has been investigated. Because of astigmatic characteristic of such display, the focal points of horizontal and vertical
directions differ in longitudinal direction. Assuming that the accommodation response to the astigmatic image follows
the distance where the average of bandwidths in vertical and horizontal direction becomes the maximum, numerical
calculations presented that the accommodation restrictedly follows three-dimensional point near the display panel. To
verify the consequence obtained by numerical calculations, experiments has been performed using keratometer to
measure the accommodation under the situation similar to horizontal-only super-multiview display. The images focused
by a cylindrical lens have been provided as stimuli to avoid argues related to the resolution of pixel pitch of display
panel. The measured results show that the accommodation response restrictedly follows astigmatic image as expected by
numerical calculations, however the quantitative investigation is still needed.
KEYWORDS: 3D image reconstruction, 3D image processing, 3D displays, Lenticular lenses, RGB color model, Error analysis, Integral imaging, Image analysis, Lenses, Distortion
In three-dimensional (3D) display based on lenticular lens method, the focal mode in which the gap between lens and
display panel is almost equal to the focal length is widely used nowadays. However, because each pixel of the display
panel has a finite size, reconstructed 3D image is displayed in virtual mode instead of focal mode. Because the elemental
image which is a source of reconstructed image was generated for focal mode, the 3D image could suffer from image
distortion. In this paper, view image error analysis based on autostereoscopic lenticular lens method and integral imaging
method is presented based on numerical analysis and simulation results.
Accommodative response measurement according to angular resolution in autostereoscopic display based on lenticular
lens and lens array method is presented. Conflict between accommodation and convergence is one of the most dominant
factors leading to visual fatigue in viewing three-dimensional display. The conflict originates from directional rays that
do not have enough angular resolution density. Therefore the purpose of this paper is to verify the relationship between
angular resolution density of elemental images and accommodation-convergence conflict. For measurement of
accommodation response of a single eye, we used lens arrays and elemental images with different resolution densities.
Three-dimensional (3D) display has attracted considerable attention in recent years because of development in display
technology. Various methods for realizing 3D display have been proposed; among them, multi-view display could be
practical to implement before aspiring 3D display. The term of multi-view display system based on autostereoscopic
display has the meaning of view splitting; the view images are projected to the pre-defined positions from the same
display device. Therefore the users located at the correct positions can see corresponding images. Although the multi-view
display technique has been studied by many research groups, the fundamental importance of the sound with display
has not, so far, been noticed nor has been examined in detail. The purpose of this paper is to realize a multi-view display
system with directional sound, which allows the individual observer to experience directional sound in multi-view
display environment. The explanation and experimental results of the proposed system are provided.
In this paper, a high-definition integral floating display is implemented. Integral floating display is composed of an
integral imaging system and a floating lens. The integral imaging system consists of a two-dimensional (2D) display and
a lens array. In this paper, we substituted multiple spatial light modulators (SLMs) for a 2D display to acquire higher definition. Unlike conventional integral floating display, there is space between displaying regions of SLMs. Therefore, SLMs should be carefully aligned to provide continuous viewing region and seamless image. The implementation of the system is explained and three-dimensional (3D) image displayed by the system is represented.
The 3D-2D convertibility is essential for the penetration of the 3D display into the current 2D display market and various methods were proposed to realize it. In this paper, a thin size 3D-2D convertible display using a pinhole array on a polarizer is proposed. The thickness of the proposed system can be below one centimeter. Additionally, the use of a pinhole array on a polarizer enhances the light efficiency of the proposed system in the 2D mode by more than ten times of the 3D mode. This is also essential since the 3D mode is an additional function for a 3D-2D convertible system. As a result, the 2D image quality of the proposed system can be compatible with the existing 2D displays for most aspects. The method is proven by experimental results.
Optical code division multiple access (O-CDMA) technique, which is considered as one of the most robust multiple-access techniques for future all-optical network has been studied in many groups. To make O-CDMA system more applicable for networks and switching, rapidly-tunable O-CDMA codes are required. The conventional coders have been reported including fiber Bragg gratings, arrayed-waveguide grating (AWG) devices and optical delay lines. And different types of CDMA coders are being proposed in many research groups. But among them, there are few coders which are freely tunable in real communication. In this paper, we propose an application of the polymer holographic grating as a tunable encoder or label swapper in O-CDMA systems. The polymer holographic grating can be an attractive approach to the spread-space, spread-spectrum CDMA systems or other combined types. The polymer holographic grating can be used for spreading and dispreading the energy of the information signal over a larger and smaller spatial domain in holographic or spread-space CDMA systems, which can be useful wireless optical communication systems. And also, it can be used in other types of CDMA systems. An application of the cyclic property of the proposed device will also be discussed.
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