Minsik Park

A design of a streaming system for interactive television broadcast

This paper describes architecture of a streaming system for interactive digital television broadcast, using MPEG-4/7 technology in delivering interactive services. The streaming system complies with ATSC (Advanced Television Systems Committee) Digital Television Standard, and delivers data of all types in ATSC Data Broadcast specification. The streaming system provides transport streams conforming to MPEG-2 systems, and has been implemented on the basis of software, and in several parts in hardware.

Interactive broadcast terminal system using MPEG-2 and MPEG-4

Interactive broadcast terminal system was designed for bidirectional interactive television service based on the MPEG-2/4 standards and ATSC broadcast specification. In order to implement user interactivity, MPEG-4 contents are carried by MPEG-2 PES or private section. Additional information combined as XML format is transmitted by DSM-CC data carousel while ATSC-PSIP is used to transfer the EPG information. IP is used to handle the bi-directional user interaction data through return channel.

System Aspects of TV-Anytime Metadata Codec in a Uni-directional Broadcasting Environment

Digital broadcasting environment in which digitalized AV contents can be sent has a room for data transmission as well. In this circumstance, effective encoding method of verbose XML type TV-Anytime metadata becomes important and also the broadcasting environment-specific refinement of TV-Anytime transportation specification is in great need. This paper suggests a well-tuned framework for encoding TV-Anytime metadata. Our TV-Anytime codec, the main subject of this paper, includes revision of the whole TVA codec system specification and external programming interfaces to communicate with the external modules in our unidirectional broadcasting head-end system.

Face and eye tracking for sub-hologram based digital holographic display system

Sub-hologram based holographic display method is one of the most practical approaches for realizing big size holographic display. However, this method needs highly accurate face and eye tracking function in real-time to enable precise steering of backlight and generation of corresponding sub-hologram for each video frame. We theoretically estimated several parameters, such as accuracy, speed and distance from an observer, required for the eye tracking function and developed an eye tracking system whose objective is accurate and fast 3D positioning of left and right pupils of an observer. Experimental results show that the system obtains accurate 3D pupil positions with an error less than 3 mm at 30 frames per second under disturbing conditions such as more than 2m distance and an observer wearing glasses. Therefore, our implementation could be sufficiently applied to the sub-hologram based display system.

Data broadcast metadata based on PMCP for open interface to a DTV data server

DTV data broadcasting offers broadcasters the new business model to acquire considerable revenue from digital broadcast. When the broadcasters integrate and maintain the data broadcast station system, they encounter the cost to be paid unnecessarily because there is no common interface specification among the equipments of DTV station system. This paper describes the flexible and open interface that will decrease the wasteful expenses in moving the transition to data broadcast station system.

Design options for 360 degree viewable table-top digital color holographic displays

We have designed and successfully implemented 360-degree viewable holographic display prototype systems. Core idea of the system design lies in the exploitation of fast operating speed of DMD for binary amplitude modulation of light field, being distributed to more than 1,000 viewpoints along the 360 degree viewing circumference. Slanted downward viewing angle and 360 degree viewable 3-dimensional(3D) image over the center of tabletop display is achieved by specially designed optics. As a result, solid-looking 3D moving color images of larger than 3 inches are rendered and observed by several viewers at the same time from different viewing positions. We have implemented and experimented several variations of the system. They are tiling of SLM modules(2x2 tiling with 4 DMDs for mono-color display and 1x2 tiling with 6 DMDs for color display), using different SLMs(DMD of pixel pitch 13.68μm and resolution 1,024x768, DMD of pixel pitch 10.8μm and resolution 1,920x1,200), and applying different structure of image floating optics((1)double parabolic mirrors, (2)one parabolic mirror and one beam splitter, (3)two spherical and one flat mirror). We report the result of various display system implementations based on several combinations of above-mentioned design options.

Improving image quality of 360-degree viewable holographic display system by applying a speckle reduction technique and a spatial filtering

Generally in electronic holographic display systems, coherent light sources are used to reconstruct holograms. The random distribution of phase profile of an object image causes unwanted dark and bright spots to degrade reconstructed hologram images. In addition, a periodic structure of available spatial light modulators such as liquid crystal on silicon devices and digital micro-mirror devices generates various diffractive signals when they are illuminated by coherent light sources. Consequently, it is necessary to select a proper signal band in spatial frequency domain by effectively filtering out unwanted signals. In this paper, the speckle pattern in a table-top holographic display system is measured and the method for reducing the speckle patterns is to be shown.

360-degree color hologram generation for real 3D objects

Recently, holographic display and computer-generated holograms calculated from real existing objects have been more actively investigated to support holographic video applications. In this paper, we proposed a method of generating 360-degree color holograms of real 3D objects in an efficient manner. 360-degree 3D images are generated using the actual 3D image acquisition system consisting of a depth camera and a turntable and intermediate view generation. Then, 360-degree color holograms are calculated using a viewing-window-based computer-generated hologram. We confirmed that floating 3D objects are faithfully reconstructed around a 360-degree direction using our 360-degree tabletop color holographic display.

An optical method for compensating phase discontinuity in a 360-degree viewable tabletop digital holographic display system

In this paper, we use an optical method for the implementation of spatially-tiled digital micro-mirror devices (DMDs) to expand space bandwidth product in general digital holographic display systems. In concatenating more than two spatial light modulators (SLMs) optically, there may exist both phase discontinuity and amplitude mismatching of hologram images emanating from two adjacent SLMs. To observe and estimate those properties in digital holographic display systems, we adopt quantitative phase imaging technique based on transport of intensity equation.

Extended viewing-angle holographic display with optical fiber arrays backlight

We present an extended viewing angle holographic three-dimensional display system using optical fiber arrays backlight and a pupil-tracking technique. One of the limitations in implementing a wide viewing-angle holographic three dimensional display is the restrictive space-bandwidth product of the spatial light modulator. In our proposed method, the optical fiber arrays backlight with pupil-tracking system enables to enlarge the static viewing angle of the holographic reconstruction using only one spatial light modulator.