Young-Kee Ryu

The Study of Improving the Accuracy in the 3D Data Acquisition of Motion Capture System

We introduced the motion capture system using two CCD cameras recently, but could not show any better accuracy than a system using PSD camera. In this paper, we propose two kinds of method to improve the accuracy of the 3D acquisition of the motion capture system using CCD cameras. The applied methods are a distortion removal and z-axis adjustment. We show the result how much the accuracy on the 3D acquisition system improved through comparing with the previous system.

A study on enhanced algorithms for detecting defects of glasses

In this paper, we proposed image processing algorithms and developed the vision system for measuring blisters of flat glasses. The images captured by changing focus of camera because the depth of field of CCD camera is smaller than the depth of glasses and classified two types in blister as circle and ellipse types by the proposed criteria of measurement. We applied different methods to each type to improve the accuracy. In the pre-processing, it obtained binarized images to find blister. The information such as area, boundary, length, and position of blister has extracted from the binarized images by using chain code algorithm. For an illumination, the bright field illumination as back-light was applied. We tested the automatic measurement system, which we developed by using vision system, It successes 100% for detecting the blister at all glasses, and the error accuracy of information is about +/-10%.

Wireless Power Transmission Technology for Implantable Telemetry Device based on Multiple Transmit Coils

The implanted telemetry system provides the monitoring of species while they move within their cages. Species monitored include mice, rats, rabbits, dogs, pigs, primates, sheep, horses, cattle, and others. A miniature transmitter implanted in each animal measures one or more parameters. Parameters measured include arterial pressure, intra-pleural pressure, left ventricular pressure, intra-ocular pressure, bladder pressure, ECG, EMG, EEG, EOG, temperature, activity, and other parameters and transmits the data via radio frequency signals to a nearby receiver. Every conventional dedicated transmitter contains one or more sensors, cpu and battery. Due to the expected life of battery, the measuring time is limited. To overcome these problems, electromagnetic inductive coupling based wireless power transmission technology using multiple transmit coils were proposed. Each coil having different active area are driven by the coil driver. In this research, parallel resonance based coil driver was proposed. In addition, the device to detect where the receiver is positioned was proposed. From the experiments we show how to determine the driving condition of coil driver.

An Implementation of OPC Client for Display Inspection System

OPC is the preferred communication standard for sharing process control data at all levels of the enterprise and becomes the global standard, sends/receives the data with PLC programs of inspection system via network, and manages various data using OPC server. In this paper, we introduce the developed OPC client system for FPD inspection system with OPC server. To control inspection system through OPC server, we have developed libraries which consist of stage driver, switch driver, microscope driver, image processing, alignment, and task management modules. Also we have developed the test program to verify all functions precisely. We describe the mechanism of inspection system, OPC connection method, and programs.

A Portable Micro-display Driver and Device for Vision Improvement

There are many visual enhancement devices for people with low vision. However, almost conventional devices have been simple magnifying and high cost. The symptoms of people with low vision are very variety. It needs to control of image magnifying, brightness, and contrast to improve the visuality. We developed a portable microdisplay driver and device for visual enhancement. This device based on our suggested four methods such as image magnifying, specific color control, BLU brightness control, and visual axis control using a prism. The basic clinical experiments of the proposed Head Mounted Visual Enhancement Device (HMVED) have been performed. The results show beneficiary effects compared with conventional devices, and improve the life quality on people with low vision on account of low weight, low cost, and easy portability.

A 3D coordinate estimation by using reformed two IR LED markers and PSD camera

We introduced a low-cost and compact motion capture system which enables to play motion games in Play Station 2[1]. The Single-PSD motion capture system that used the intensity light of a marker has a weak measurement at an intensity variation. It is so difficult to make markers having omni-direction equal intensity in Single-PSD. In this paper, we propose a new method that solves aforementioned problems. It can measure 3D coordination with the relation of the optical characteristics if the intensity of a pair of markers is same at forward direction. We made a system based on this proposed method and experimented for performance capability. As a result, we were able to make the motion capture system to the robust system for bad factors, such as variation intensity of markers, external light. The system is stable to obtain 3d positions and an adaptable motion games. The improved system is expected to be useful in animation, movies and games.

Development of a Real Time Three-Dimensional Motion Capture System by Using Single PSD Unit

Motion capture systems are gaining popularity in entertainment, medicine, sports, education, and industry, with animation and gaming applications for entertainment taking the lead. A wide variety of systems are available for motion capture, but most of them are complicated and expensive. In the general class of optical motion capture, two or more optical sensors are needed to measure the 3D positions of the markers attached to the body. Recently, a 3D motion capture system using two Position Sensitive Detector (PSD) optical sensors was introduced to capture high-speed motion of an active infrared LED marker. The PSD-based system, however, is limited by a geometric calibration procedure for two PSD sensor modules that is too difficult for common customers. In this research, we have introduced a new system that used a single PSD sensor unit to obtain 3D positions of active IR LED-based markers. This new system is easy to calibrate and inexpensive.