The Experts below are selected from a list of 3381 Experts worldwide ranked by ideXlab platform

Yasuhiro Takaki - One of the best experts on this subject based on the ideXlab platform.

  • Multi-channel viewing-zone scanning Holographic Display
    Imaging and Applied Optics 2016, 2016
    Co-Authors: Mitsuki Nakaoka, Yasuhiro Takaki
    Abstract:

    A multi-channel viewing-zone scanning Holographic Display that enables an increase in the screen size using multiple projection systems is proposed. A screen size of 7.4 in and viewing-zone width of 630 mm are demonstrated.

  • Measurements of accommodation responses to horizontally scanning Holographic Display
    Practical Holography XXVI: Materials and Applications, 2012
    Co-Authors: Masahito Yokouchi, Yasuhiro Takaki
    Abstract:

    Because holography can reconstruct the wavefront of the light emitted from an object, eyes might focus on Holographically generated three-dimensional (3D) images. Therefore, eye accommodation is considered to function properly for Holographic 3D images. However, the measurement of the accommodation responses to 3D images generated by electronic Holographic Displays have not been reported, because their viewing zone angle and screen size are limited and the observation of the reconstructed 3D images with both eyes is difficult. In the recent study, we have developed a horizontally scanning Holographic Display that enables the increase of both horizontal viewing zone angle and screen size. The reconstructed images can be observed with both eyes. In this study, we measured the accommodation responses to the 3D images generated by the horizontally scanning Holographic Display. We found that the accommodation responses to the 3D images were similar to the responses to real objects.

  • Accommodation measurements of horizontally scanning Holographic Display.
    Optics express, 2012
    Co-Authors: Yasuhiro Takaki, Masahito Yokouchi
    Abstract:

    Eye accommodation is considered to function properly for three-dimensional (3D) images generated by holography. We developed a horizontally scanning Holographic Display technique that enlarges both the screen size and viewing zone angle. A 3D image generated by this technique can be easily seen by both eyes. In this study, we measured the accommodation responses to a 3D image generated by the horizontally scanning Holographic Display technique that has a horizontal viewing zone angle of 14.6° and screen size of 4.3 in. We found that the accommodation responses to a 3D image Displayed within 400 mm from the Display screen were similar to those of a real object.

  • Zone plate method for electronic Holographic Display using resolution redistribution technique
    Optics express, 2011
    Co-Authors: Yasuhiro Takaki, Junya Nakamura
    Abstract:

    The resolution redistribution (RR) technique can increase the horizontal viewing-zone angle and screen size of electronic Holographic Display. The present study developed a zone plate method that would reduce hologram calculation time for the RR technique. This method enables calculation of an image Displayed on a spatial light modulator by performing additions of the zone plates, while the previous calculation method required performing the Fourier transform twice. The derivation and modeling of the zone plate are shown. In addition, the look-up table approach was introduced for further reduction in computation time. Experimental verification using a Holographic Display module based on the RR technique is presented.

  • Grayscale image reconstruction by horizontally scanning Holographic Display
    Digital Holography and Three-Dimensional Imaging, 2011
    Co-Authors: Masahito Yokouchi, Yasuhiro Takaki
    Abstract:

    The grayscale image reconstruction by the horizontally scanning Holographic Display is improved. Several sets of elementary holograms are Displayed with different illumination laser powers in a time-multiplexing manner. Four hologram design methods are compared.

Jinwoong Kim - One of the best experts on this subject based on the ideXlab platform.

  • ICTC - Measurement of brightness performance in viewing window based electronic Holographic Display system
    2020 International Conference on Information and Communication Technology Convergence (ICTC), 2020
    Co-Authors: Hayan Kim, Yongjun Lim, Jinwoong Kim
    Abstract:

    In this paper, we propose a method for evaluating the brightness performance of reproduced Holographic images by quantitatively measuring its optical power in a viewing-window based electronic Holographic Display system. In general, lasers as coherent light sources are adopted in the playback process of digital holograms. The laser light source used to reproduce the hologram is one of the important factors that greatly affect the brightness performance. By considering the optical properties of light source, we will quantitatively measure and evaluate it on the viewing-window based electronic Holographic Display system. To evaluate the brightness performance perceived by the human eye, we will present the approach to convert the measured optical power of hologram image signal into photometric term. By referring to our proposed method, it is expected to suggest how to measure and improve the brightness of the viewing-window based electronic Holographic Display system.

  • Electronic Tabletop Holographic Display: Design, Implementation, and Evaluation
    MDPI AG, 2019
    Co-Authors: Jinwoong Kim, Joongki Park, Hayan Kim, Joonku Hahn, Keehoon Hong, Yongjun Lim, Hyun-eui Kim, Jeho Nam, Young-ju Kim
    Abstract:

    Most of the previously-tried prototype systems of digital Holographic Display are of front viewing flat panel-type systems having narrow viewing angle, which do not meet expectations towards Holographic Displays having more volumetric and realistic 3-dimensional image rendering capability. We have developed a tabletop Holographic Display system which is capable of 360° rendering of volumetric color hologram moving image, looking much like a real object. Multiple viewers around the Display can see the image and perceive very natural binocular as well as motion parallax. We have previously published implementation details of a mono color version of the system, which was the first prototype. In this work, we present requirements, design methods, and the implementation result of a full parallax color tabletop Holographic Display system, with some recapitulation of motivation and a high-level design concept. We also address the important issue of performance measure and evaluation of a Holographic Display system and image, with initial results of experiments on our system

  • Experimental Evaluation of Spatial Resolution and Depth of Focus in Digital Holographic Display
    Frontiers in Optics + Laser Science APS DLS, 2019
    Co-Authors: Keehoon Hong, Jinwoong Kim, Hayan Kim, Yongjun Lim, Jeongil Seo
    Abstract:

    We propose a method to measure spatial resolution and depth of focus of reconstructed hologram images, which can be applied to general digital Holographic Displays. Experimental results for a projection-type Holographic Display are presented.

  • 3D MTF for the Image Quality Assessment of Holographic Display System
    2018
    Co-Authors: Joongki Park, Jinwoong Kim, Eun-young Chang, Hayan Kim, Jae-han Kim, Minsik Park
    Abstract:

    Holographic Displays are ideal imaging technologies because they allow objects to be reconstructed three-dimensionally to any desired distance without an accommodation convergence conflict. Therefore, unlike traditional two-dimensional Displays, measurement of the image quality of a Holographic Display is based on an image reconstructed in three-dimensional space. In this paper, we propose a 3D MTF measurement method as a quantitative evaluation method for the image quality of Holographic Displays. We show the experimental result of our tabletop Holographic Display by exploiting the proposed method.

  • Measurement and reduction of speckle phenomenon in a 36 degree viewable Holographic Display system
    2018 Joint Symposia on Optics, 2018
    Co-Authors: Yongjun Lim, Jinwoong Kim, Keehoon Hong, Jae-hyeung Park
    Abstract:

    In digital Holographic Display systems, lasers are widely adopted as light sources in retrieving holograms. In addition, random phase profile is applied in calculating computer generated holograms, which causes granular patterns, i.e. speckles, composed of dark and bright spots so that it affects the image quality of reconstructed holograms. In this paper, we propose a method to measure and estimate speckle patterns in our recently-developed 360-degree tabletop Holographic Display systems.

Yongtian Wang - One of the best experts on this subject based on the ideXlab platform.

  • multichannel vectorial Holographic Display and encryption
    arXiv: Optics, 2019
    Co-Authors: Ruizhe Zhao, Yongtian Wang, Basudeb Sain, Qunshuo Wei, Chengchun Tang, Thomas Weiss, Lingling Huang, Thomas Zentgraf
    Abstract:

    Since its invention, holography has emerged as a powerful tool to fully reconstruct the wavefronts of light including all the fundamental properties (amplitude, phase, polarization, wave vector, and frequency). For exploring the full capability for information storage/Display and enhancing the encryption security of metasurface holograms, smart multiplexing techniques together with suitable metasurface designs are highly demanded. Here, we integrate multiple polarization manipulation channels for various spatial phase profiles into a single birefringent vectorial hologram by completely avoiding unwanted cross-talk. Multiple independent target phase profiles with quantified phase relations that can process significantly different information in different polarization states are realized within a single metasurface. For our metasurface holograms, we demonstrate high fidelity, large efficiency, broadband operation, and a total of twelve polarization channels. Such multichannel polarization multiplexing can be used for dynamic vectorial Holographic Display and can provide triple protection for optical security. The concept is appealing for applications of arbitrary spin to angular momentum conversion and various phase modulation/beam shaping elements.

  • 21-inch color 3D dynamic Holographic Display
    Digital Holography and Three-Dimensional Imaging 2019, 2019
    Co-Authors: Juan Liu, Tao Zhao, Yu Han, Yongtian Wang
    Abstract:

    A compact Display system is proposed for color dynamic Holographic Display with a 21-inch liquid crystal Display (LCD) panel. An independent block Holographic algorithm is developed to record accurate depth information.

  • Color dynamic Holographic Display by complex amplitude modulation
    Imaging and Applied Optics 2018 (3D AO AIO COSI DH IS LACSEA LS&C MATH pcAOP), 2018
    Co-Authors: Juan Liu, Tao Zhao, Yongtian Wang
    Abstract:

    An improved method of complex amplitude modulation (CAM) is proposed for color dynamic Holographic Display with a wide viewing angle. Band-limited random initial phase is introduced to enlarge the field of view for 3D Display.

  • The optimizations of CGH generation algorithms based on multiple GPUs for 3D dynamic Holographic Display
    Advanced Laser Manufacturing Technology, 2016
    Co-Authors: Dan Yang, Juan Liu, Yingxi Zhang, Yongtian Wang
    Abstract:

    Holographic Display has been considered as a promising Display technology. Currently, low-speed generation of holograms with big Holographic data is one of crucial bottlenecks for three dimensional (3D) dynamic Holographic Display. To solve this problem, the acceleration method computation platform is presented based on look-up table point source method. The computer generated holograms (CGHs) acquisition is sped up by offline file loading and inline calculation optimization, where a pure phase CGH with gigabyte data is encoded to record an object with 10 MB sampling data. Both numerical simulation and optical experiment demonstrate that the CGHs with 1920×1080 resolution by the proposed method can be applied to the 3D objects reconstruction with high quality successfully. It is believed that the CGHs with huge data can be generated by the proposed method with high speed for 3D dynamic Holographic Display in near future.

  • multiplexing encoding method for full color dynamic 3d Holographic Display
    Optics Express, 2014
    Co-Authors: Gaolei Xue, Juan Liu, Jia Jia, Zhao Zhang, Yongtian Wang
    Abstract:

    The multiplexing encoding method is proposed and demonstrated for reconstructing colorful images accurately by using single phase-only spatial light modulator (SLM). It will encode the light waves at different wavelengths into one pure-phase hologram at the same time based on the analytic formulas. The three-dimensional (3D) images can be reconstructed clearly when the light waves at different wavelengths are incident into the encoding hologram. Numerical simulations and optical experiments for 2D and 3D colorful images are performed. The results show that the colorful reconstructed images with high quality are achieved successfully. The proposed multiplexing method is a simple and fast encoding approach and the size of the system is small and compact. It is expected to be used for realizing full-color 3D Holographic Display in future.

Tomasz Kozacki - One of the best experts on this subject based on the ideXlab platform.

  • Visual perception of Fourier rainbow Holographic Display
    Electronics and Telecommunications Research Institute (ETRI), 2019
    Co-Authors: Hyon‐gon Choo, Maksymilian Chlipala, Tomasz Kozacki
    Abstract:

    The rainbow hologram provides views of reconstruction with rainbow color within a large viewing zone. In our recent paper, a Fourier rainbow Holographic Display using diffraction grating and a white‐light LED source was introduced. In this technique, the rainbow effect is realized by the dispersion of white‐light source on diffraction grating, while the slit is implemented numerically by reducing the demands of the space‐bandwidth product of the Display. This paper presents a novel analysis on the visual perception of the Fourier rainbow Holographic Display using Wigner distribution. The view‐dependent appearance of the image, including multispectral field of view and viewing zone, is investigated considering the observer and the Display parameters. The resolution of the Holographic view is also investigated. For this, a new quantitative assessment for image blur is introduced using Wigner distribution analysis. The analysis is supported with numerical simulations and experimentally captured optical reconstructions for the holograms of the computer model and real object generated with different slit size, reconstruction distance, and different observation conditions

  • Image Blur and Visual Perception for Rainbow Holographic Display
    Optics Photonics and Digital Technologies for Imaging Applications V, 2018
    Co-Authors: Hyon-gon Choo, Maksymilian Chlipala, Tomasz Kozacki
    Abstract:

    The rainbow hologram provides observation of the reconstructed object with different spectra over different viewing position. Recently, we’ve proposed a concept of digital rainbow Holographic Display using diffraction grating and white LED lighting source. In the technique, the slit is implemented numerically by reducing the frequency of the hologram, while the rainbow effect is realized by dispersion of white light source on the diffraction grating. Phase only SLM with 4F imaging system is used for implementation of complex wave fields. For classical rainbow hologram, image blur is known to be very important key point regarding Holographic image quality. In this paper, we analyze image blur and visual perception for digital rainbow Holographic Display. The quality of reconstructed rainbow holograms is investigated under varying viewing conditions regarding visual perception and depth resolution. In experiments, the visual properties of the digital rainbow hologram are analyzed using optical reconstructions for the hologram of 3D and 2D objects of different depth.

  • Holographic Display with LED sources illumination and enlarged viewing angle
    Photonics Applications in Astronomy Communications Industry and High-Energy Physics Experiments 2016, 2016
    Co-Authors: Maksymilian Chlipala, Tomasz Kozacki
    Abstract:

    In this work we present Holographic Display that uses LED sources illumination and have enlarged viewing angle. In this Holographic Display design we employ phase only SLM because it allows to obtain reconstructions of high quality. Our setup realizes complex coding scheme and allows to reconstruct complex Holographic images. Thus reconstruction of inplane holograms is possible. Holograms Displayed on SLM are computer generated. For enlargement of angular field of view we use three spatially separated illumination sources and time multiplexing technique. In experimental part, where we Display computer generated holograms, we show that it is possible to obtain Holographic reconstructions of 3D object with extended viewing angle.

  • color Holographic Display with white light led source and single phase only slm
    Optics Express, 2016
    Co-Authors: Tomasz Kozacki, Maksymilian Chlipala
    Abstract:

    This work presents color Holographic Display, which is based on a single phase only spatial light modulator (SLM). In the Display entire area of the SLM is illuminated by an on-axis white light beam generated by a single large LED. The Holographic Display fully utilizes SLM bandwidth and has capability of full-color, full frame rate imaging of outstanding quality. This is achieved through: (i) optimal use of the source coherence volume, (ii) application of the single white light LED source, (iii) a development of a novel concept of color multiplexing technique with color filter mask in Fourier plane of the SLM, (iv) and a complex coding with improved diffraction efficiency. Within experimental part of the paper we show single color, full-color Holographic 2D and 3D images generated for reconstruction depth exceeding 10 cm.

  • extended viewing angle Holographic Display system with tilted slms in a circular configuration
    Applied Optics, 2012
    Co-Authors: Tomasz Kozacki, Grzegorz Finke, Malgorzata Kujawinska, Bryan M Hennelly, Nitesh Pandey
    Abstract:

    This paper presents an extended viewing angle Holographic Display for reconstruction of real world objects in which the capture and Display systems are decoupled. This is achieved by employing multiple tilted spatial light modulators (SLMs) arranged in a circular configuration. In order to prove the proper reconstruction and visual perception of Holographic images the Wigner distribution function is employed. We describe both the capture system using a single static camera with a rotating object and a Holographic Display utilizing six tilted SLMs. The experimental results based on the reconstruction of computer generated and real world scenes are presented. The coherent noise removal procedure is described and implemented. The experiments prove the possibility to view images reconstructed in the Display binocularly and with good quality.

Byoungho Lee - One of the best experts on this subject based on the ideXlab platform.

  • wide angle speckleless dmd Holographic Display using structured illumination with temporal multiplexing
    Optics Letters, 2020
    Co-Authors: Byounghyo Lee, Dukho Lee, Jinsoo Jeong, Dongheon Yoo, Seungjae Lee, Byoungho Lee
    Abstract:

    We propose a digital micromirror device (DMD) Holographic Display, where speckleless holograms can be observed in the expanded viewing zone. Structured illumination (SI) is applied to expand the small diffraction angle of the DMD using a laser diode (LD) array. To eliminate diffraction noise from SI, we utilize an active filter array for the Fourier filter and synchronize it with the LD array. The speckle noise is reduced via temporal multiplexing, where the proposed system supports a dynamic video of 60 Hz using the DMD’s fast operation property. The proposed system is verified and evaluated with experimental results.

  • Holographic Display for Uniform Energy High Order Terms
    Frontiers in Optics Laser Science, 2020
    Co-Authors: Dukho Lee, Kiseung Bang, Byoungho Lee
    Abstract:

    We present a method to generate uniform energy signal wave without energy loss for Holographic Display. The proposed method was confirmed by experiments. Experimental results show that the reconstructed signal wave has flat energy envelope.

  • A Method for Increasing the Resolution of Holographic Display Using LED
    Imaging and Applied Optics 2019 (COSI IS MATH pcAOP), 2019
    Co-Authors: Dukho Lee, Seokil Moon, Byounghyo Lee, Byoungho Lee
    Abstract:

    In this paper, we propose a method to increase the resolution of Holographic Display using LED. The method increases the spatial coherence of the reference wave for Holographic Display. The proposed method is experimentally verified.

  • Comparison between LED and LD as a light source for near-eye Holographic Display
    Speckle 2018: VII International Conference on Speckle Metrology, 2018
    Co-Authors: Dukho Lee, Byoungho Lee
    Abstract:

    In this paper, we analyze the image quality reconstructed by Holographic Display depending on spatial coherency and temporal coherency of the light source in Holographic Display system. The simulation was conducted by changing both spatial coherency and temporal coherency independently using proper modeling of coherency. A Holographic Display setup was composed to verify simulation results. LED and LD were respectively used as a light source for Holographic Display, and the quality of reconstructed images reproduced by using LED or LD was compared. The scheme of near-eye Holographic Display adopting LED as a light source which generates low speckle noise but narrow depth range was proposed. The proposed scheme of near-eye Holographic Display system was verified experimentally.

  • DC-free on-axis Holographic Display using a phase-only spatial light modulator.
    Optics letters, 2018
    Co-Authors: Jaebum Cho, Byoungho Lee, Soobin Kim, Shin-woong Park, Hwi Kim
    Abstract:

    A DC-noise-free on-axis Holographic Display scheme using a phase-only spatial light modulator (SLM) is proposed. The origin of DC noise in the on-axis Holographic Display using a phase-only SLM is analyzed, and a DC noise rejection filter is optimized for a phase-only SLM is designed. A novel two-step iterative Fourier transform algorithm for the optimal synthesis of a phase-only computer-generated hologram using the proposed scheme is devised. The proposed scheme and algorithm are validated with numerical simulations and experiments.