• Journal of Korea Foundry Society
• /
• v.29 no.3
• /
• pp.144-149
• /
• 2009

In this study, we investigated optimum condition of cooling plate method to obtain semi-solid AM100A Mg alloy with fine and globular morphology. AM100A Mg alloy were hot extruded at $380^{\circ}C$ extrusion temperature under extrusion ratio of 25 : 1 and ram speed of 2.4 mm/sec. Vickers hardness test, optical microscopy, scanning electron microscopy, and image analyzer were performed to identify the optimum conditions of cooling plate method. Optimum conditions of cooling plate method to fabricate semi-solid AM100A Mg alloy with fine and globular microstructures were achieved at a pouring temperature of $602^{\circ}C$ and the angle of cooling plate of 60 degree.

• Journal of the Korean Society of Visualization
• /
• v.3 no.1
• /
• pp.26-35
• /
• 2005

The combination of ultrasound echo images with digital particle image velocimetry (DPIV) method has resulted in a two-dimensional, two-component velocity field measurement technique appropriate for opaque flow conditions including blood flow in clinical applications. Advanced PIV processing algorithms including an iterative scheme and window of offsetting were used to increase spatial resolution. The optimum concentration of the ultrasound contrast agent used for seeding was explored. Velocity validation tests in fully developed laminar pipe flow and pulsatile flow showed good agreement with both optical PIV measurements and the known analytic solution. These studies indicate that echo PIV is a promising technique for the non-invasive measurement of velocity profiles and shear stress.

• Journal of Korea Multimedia Society
• /
• v.18 no.3
• /
• pp.349-358
• /
• 2015

Simulating color appearance of makeup effect is an important issue in computer graphics as well as cosmetic industry. Most of previous works on makeup simulation are simple color blending to mimic the cosmetic effects. Some of previous works employed Kubelka-Munk model to accurately simulate the layering effect of cosmetics. However, the simulation limited on single point, and the rest of area are still computed by simple color blending utilizing the color of the single point simulation. This paper presents an image-based method to compute the color appearance effect of makeup application using per-pixel Kubelka-Munk model. Unlike the previous methods, it is possible to compute per-pixel application thickness as well as optical property of cosmetics. The computed thickness pattern can be used in makeup simulation for a more realistic makeup simulation.

• Korean Journal of Optics and Photonics
• /
• v.15 no.5
• /
• pp.405-408
• /
• 2004

In this paper, we used a split-lens speckle shear interferometer using a double speckle interferometer, which enables continuous measurement of the deformation. We made two identical specklegrams corresponding to an object. With this method we could detect the measuring limits of the deformation for various shears. This experimental results showed that the measuring limits of a split-lens speckle shear interferometer are similar to the measuring limits of a double exposure speckle interferometer.

• Journal of the Korean Institute of Telematics and Electronics B
• /
• v.31B no.6
• /
• pp.10-16
• /
• 1994

In case of off-line character recognition with statistical method, the character recognition speed for Korean or Chinese characters is slow since the amount of calculation is huge. To improve this problem, we seperate the recognition steps into several functional stages and implement them with hardwares for each stage so that all the stages can be processed with pipline structure. In accordance with temporal parallel processing, a high speed character recognition system can be implemented. In this paper, we implement a classification hardware, which is one of the several functional stages, to improve the speed by parallel structure with multiple DSPs(Digital Signal Processors). Also, it is designed to be able to expand DSP boards in parallel to make processing faster as much as we wish. We implement the hardware as an add-on board in IBM-PC, and the result of experiment is that it can process about 47-times and 71-times faster with 2 DSPs and 3 DSPs respectively than the IBM-PC(486D$\times$2-66MHz). The effectiveness is proved by developing a high speed OCR(Optical Character Recognizer).

• Korean Journal of Computational Design and Engineering
• /
• v.19 no.1
• /
• pp.68-79
• /
• 2014

Human model simulation has been widely used in various industrial areas such as ergonomic design, product evaluation and characteristic analysis of work-related musculoskeletal disorders. However, the process of building digital human models and capturing their behaviors requires many costly and time-consuming fabrication iterations. To overcome the limitations of this expensive and time-consuming process, many studies have recently presented a markerless motion capture approach that reconstructs the time-varying skeletal motions from optical devices. However, the drawback of the markerless motion capture approach is that the phenomenon of occlusion of motion data occurs in real-time human simulation. In this study, we propose a systematic method of discriminating missing or inaccurate motion data due to motion occlusion and interpolating a sequence of motion frames captured by a markerless depth camera.

• Proceedings of the Korean Society of Broadcast Engineers Conference
• /
• 2013.11a
• /
• pp.239-240
• /
• 2013

The quality of document images captured by digital camera might be degraded because of non-uniform illumination condition. The high illumination (glare distortion) affects on the contrast condition of the document images. This condition leads to the poor contrast condition of the text in document image. So, optical character recognition (OCR) system might hardly recognize text in the high illuminated area. The method to increase the contrast condition between text (foreground) and background in high illuminated area is proposed in this paper.

• Journal of the Korean Society for Precision Engineering
• /
• v.15 no.9
• /
• pp.68-74
• /
• 1998

The ESPI(Electronic Speckle Pattern Interferometry) is a real time, full-field, non-destructive optical measurement technique that allows static and dynamic deformation analysis and surface shape measurements of engineering structures. e .g. turbine blades. vehicle engine components, body panels, etc. This technique is very similar to holographic interferometry, but uses a solid static camera and an image processing board for recording and digital processing of speckle patterns. In this paper it is presented that FEM results for the free vibration of symmetrically laminated composite as [30/-30/90]s. The natural frequencies of laminated composite rectangular plates having the particular boundary condition are experimentally obtained. In order to demonstrate the validity of the experiment, FEM analysis using ANSYS was performed and natural frequencies experimentally obtained is compared with calculation by FEM analysis. The results obtained from both experiment and FEM analysis show a good agreement.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2014.10a
• /
• pp.441-444
• /
• 2014

공장 사업장 등에서 발생되는 매연은 대기오염의 원인이 될 뿐만 아니라 인체에도 나쁜 영향을 미친다. 따라서 대기오염방지를 위해 배출되는 대기오염물질을 측정하고 이를 관리하여 대기오염을 신속히 파악하고 사전에 방지하기 위한 서비스가 필요하다. 본 논문에서는 광학센싱을 이용해 굴뚝연기의 혼탁도를 측정하고 이를 다양한 모바일 운영체제에서 측정결과를 실시간으로 검색할 수 있는 모바일 웹앱을 설계하고 구현한다. 구현된 시스템에서 사용자는 다양한 모바일기기를 이용하여 굴뚝연기의 혼탁도와 VOC 오염도에 대하여 여러 가지 조건으로 검색할 수 있으며 사용자 정의값을 설정하고 이를 초과하는 경우에 지정된 번호로 알림 서비스를 제공 받을 수 있다. 또한 모바일 운영체제에 독립적인 웹앱의 형태로 제공되어 사용자의 다양한 모바일 기기에서 운영될 수 있으며 실시간으로 유지보수를 제공할 수 있는 장점이 있다.

• Korean Journal of Optics and Photonics
• /
• v.21 no.6
• /
• pp.235-240
• /
• 2010

We fabricate highly birefringent photonic crystal fiber with new structure using a stack and draw method. Fabricated fiber has two big air holes, one at each side of the outside air cladding region, leading to core ellipticity during the drawing process. Birefringence of the fabricated Hi-Bi PCF is measured to be $2.29{\times}10^{-4}$ (at 1550 nm).