• Journal of Korean Institute of Industrial Engineers
• /
• v.41 no.1
• /
• pp.59-63
• /
• 2015

A design guideline about legible and preferred Korean character sizes is necessary to provide better visual information in a group-view display. The present study examined the legible and preferred Korean character sizes by an experiment employing eight background-font colors and four representative font types (Gulim, Ming, Gothic, and Batang). Forty subjects (male : 20 and female : 20) in their 20s were recruited for the experiment. The legible and preferred sizes were determined based on the method of limits, one of psychological approaches. The results showed that the legible and preferred sizes increased as the contrast between background and font colors decreased. In addition, the legible and preferred sizes for Gulim were significantly smaller than those of the other font types. It is expected that the present study may contribute to providing better visual information in a group view display.

• Korean Journal of Computational Design and Engineering
• /
• v.20 no.4
• /
• pp.337-347
• /
• 2015

This paper presents a dynamic association and natural interaction method for multi-displays composed of smart devices. Users can intuitively associate relations among smart devices by shake gestures, flexibly modify the layout of the display by tilt gestures, and naturally interact with the multi-display by multi-touch interactions. First of all, users shake their smart devices to create and bind a group for a multi-display with a matrix configuration in an ad-hoc and collaborative situation. After the creation of the group, if needed, their display layout can be flexibly changed by tilt gestures that move the tilted device to the nearest vacant cell in the matrix configuration. During the tilt gestures, the system automatically modifies the relation, view, and configuration of the multi-display. Finally, users can interact with the multi-display through multi-touch interactions just as they interact with a single large display. Furthermore, depending on the context or role, synchronous or asynchronous mode is available to them for providing a split view or another UI. We will show the effectiveness and advantages of the proposed approach by demonstrating implementation results and evaluating the method by the usability study.

• Journal of Korea Multimedia Society
• /
• v.20 no.12
• /
• pp.2009-2015
• /
• 2017

A two-dimensional lens is required to reproduce both the horizontal and vertical parallax through an autostereoscopic 3D display. Among the two-dimensional lenses, a hexagonal micro lens array (MLA) having good optical efficiency is mainly used. However, the hexagonal MLA has complex geometric features. The first feature is that the lens cells are zigzagged in the vertical direction, which should be reflected in the view number calculation for each sub-pixel. The second feature is that the four sides of a hexagonal lens cell are tilted, requiring a more careful view index assignment to the lens cell. In this paper, we propose a sub-pixel multiplexing scheme suitable for the features of the hexagonal MLA. We also propose a view-overlay algorithm based on a two-dimensional lens and compare subjective image quality with existing view-selection through autostereoscopic 3D display implementation.

• Journal of Information Display
• /
• v.11 no.2
• /
• pp.76-83
• /
• 2010

This paper presents the multi-user autostereoscopic 3D display system constructed and operated by the authors using the time-multiplexing approach. This prototype has three main advantages over the previous versions developed by the authors: its hardware was simplified as only one optical array is used to create viewing regions in space, a lenticular multiplexing screen is not necessary as images can be produced sequentially on a fast 120Hz LCD with full resolution, and the holographic projector was replaced with a high-frame-rate digital micromirror device (DMD) projector. The whole system in this prototype consists of four major parts: a 120Hz high-frame-rate DMD projector, a 49-element optical array, a 120Hz screen assembly, and a multi-user head tracker. The display images for the left/right eyes are produced alternatively on a 120Hz direct-view LCD and are synchronized with the output of the projector, which acts as a backlight of the LCD. The novel steering optics controlled by the multiuser head tracker system directs the projector output to regions referred to as exit pupils, which are located in the viewers’eyes. The display can be developed in the "hang-on-the-wall"form.

• Journal of Broadcast Engineering
• /
• v.9 no.3
• /
• pp.236-245
• /
• 2004

A multiview sequence CODEC with view scaiability is proposed in this paper. We define a GGOP (Group of GOP) structure as a basic coding unit to efficiently code multiview sequences. 7he proposed CODEC provides flexible GGOP structures based on the number of views and baseline distances among cameras. Multiview sequences encode consists of disparity estimation/compensation, motion estimation/compensation, residual coding and rate control and generates multiview sequence bitstream. The main bitstream is the same as an MPEG-2 mono-sequence bitstream for MPEG-2 compatibility. The auxiliary bitstream contains information concerning the remaining multiview sequences except for the reference sequences. The proposed CODEC with view scalability provides that a number of view flints are selectively determined at the receiver according to the type of display modes. The proposed multiview sequence CODEC is tested with several multiview sequences to determine its flexibility. compatibility with MPEG-2 and view scaiability. In addition, we subjectively confirm that the decoded bitstreams with view scaiability can be Properly displayed by several types of display modes. including 3D monitors.

• Journal of the Ergonomics Society of Korea
• /
• v.36 no.3
• /
• pp.213-219
• /
• 2017

Objective: The present study identified the minimum legible text size by an experiment for eight combinations of background and text colors, which will be used in designing visual information on group-view display (GVD). Background: Information on minimum legible text size is needed to design the visual information presented on GVD in a radioactive waste control room. Method: The experiment was conducted for 22 male participants (age: mean = 37, SD = 6.7; visual acuity: over 0.8) who were recruited by considering demographic characteristics of current control room operators. Eight combinations of background and text colors were considered and the minimum legible text size was determined for each combination by applying the method of limits, one of psychophysical methods. Results: The minimum legible text size was significantly different in accordance with the combination of background and text colors. Statistical analysis results showed that luminance contrast and color contrast between background and text influenced the minimum legible text sizes. Conclusion: This study concluded that the minimum legible text size is 8 minute of arc for various combinations of background and text colors. Application: The minimum legible text size identified in the present study can be utilized in designing visual information on GVD at the main control room in a radioactive waste facility.

• Journal of the Optical Society of Korea
• /
• v.19 no.6
• /
• pp.614-618
• /
• 2015

This paper described an off-axis head-mounted display system. It is composed of a 7-piece coaxial relay lens group and a freeform surface combiner. This configuration has a simple structure and a wide field of view (FOV). In this design, a freeform surface is chosen as the combiner, to simplify the structure and attain good image quality. We generated this freeform surface by considering both coordinates and normals of discrete data points. Moreover, we realize a coaxial structure in the relay lens group, which is compact and benefits from a loose tolerance requirement. The HMD system we finally realized has a 40° × 30° FOV and 15-mm exit pupil diameter.

• Journal of Environmental Health Sciences
• /
• v.21 no.4
• /
• pp.75-86
• /
• 1995

This study was performed to investigate the negative side effects of video display terminal (VDT) work on the human body and to provide data for preventing VDT syndrome. A questionnaire survey was made to 339 VDT workers at 22 offices in Taegu, Kyungpook and Kyungnam areas from July 1 to August 31, 1994, and 280 of them were finally used for statistical analysis. The VDT syndrome in the present study inclhded five factors, namely as eye-related symptom, psychological symptom, general body symptom, musculoskeletal symptom, and skin-related symptom, and the estimates of Crombach coefficients of the five factors were 0.954, 0.952, 0.953, 0.957, and 0.955, respectively, showing very high reliability. In view of socio-economical characteristics, the symptoms of female were higher than those of male in the order of musculoskeletal symptom, eye-related symptom, skin-related symptom and psychological symptom. The age group of 30 years or less was higher than the older groups in the order of musculoskeletal symptom, eye-related symptom, psychological symptom and skinrelated symptom. The group of lower education level showed higher skin-related symptom. The psychological symptom and skin-related symptom increased as the amount of smoking increased. Higher eye-related symptom was observed in the group without glasses. In the job-related variables, the group of working on programming and data input showed higher eye-related symptom and psychological symptom. The group of working on programming and graphic design showed higher musculoskeletal symptom and skin-related symptom. The skin-related symptom increased as the total time of VDT operation per day increased. The group of working 2-4 hours followed by 15 minutes rest was higher in musculoskeletal symptom and psychological symptom. Higher musculoskeletal symptom was observed from the group working on Friday and Sunday. The group of 1 year or less working showed higher in skin-related symptom. In relation with the VDT type, all symptoms except skin-related symptom were higher in the group using monochrome monitor. As showed above, the questionnaire could be a tool for evaluating VDT syndrome and prevention of the syndrome would be possible by a comprehensive consideration of factors including socio-economic characteristics, job-related variables and VDT type.

• Smart Media Journal
• /
• v.1 no.3
• /
• pp.36-42
• /
• 2012

Recently, the smart applications, such as smart phone and smart TV, become a hot issue in IT consumer markets. In particular, the smart TV provides 3D video services, hence efficient coding methods for 3D video data are required. Three-dimensional (3D) video involves stereoscopic or multi-view images to provide depth experience through 3D display systems. Binocular cues are perceived by rendering proper viewpoint images obtained at slightly different view angles. Since the number of viewpoints of the multi-view video is limited, 3D display devices should generate arbitrary viewpoint images using available adjacent view images. In this paper, after we explain a view synthesis method briefly, we propose a new algorithm to compensate view synthesis errors around object boundaries. We describe a 3D warping technique exploiting the depth map for viewpoint shifting and a hole filling method using multi-view images. Then, we propose an algorithm to remove boundary noises that are generated due to mismatches of object edges in the color and depth images. The proposed method reduces annoying boundary noises near object edges by replacing erroneous textures with alternative textures from the other reference image. Using the proposed method, we can generate perceptually inproved images for 3D video systems.

• Journal of the Korean Chemical Society
• /
• v.45 no.3
• /
• pp.236-241
• /
• 2001

Europium activated yttrium oxide ($Y_2O_3$ : Eu) is extensively applied to red phosphor for Flat Panel Display because of its high efficiency and the thermal and chemical stability. Flat Panel Display screen which have a high resolution and high efficiency needs to the phosphors of ideally small size spherical particle. In this study, we prepared a $Y_2O_3$ : Eu phosphor using polymeric precursor methods and investigated the codoping effect by introducing the group 1 or 2 elements to $Y_2O_3$ : Eu phosphor in view of improvement of luminance efficiency.