• Journal of the Institute of Convergence Signal Processing
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• v.2 no.2
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• pp.28-38
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• 2001

Traffic information can be broadly categorized into point information and spatial information. Point information can be obtained by chocking only the presence of vehicles at prespecified points(small area), whereas spatial information can be obtained by monitoring large area of traffic scene. To obtain spatial information by image processing, we need to track vehicles in the whole area of traffic scene. Image detector system based on global tracking consists of video input, vehicle detection, vehicle tracking, and traffic information measurement. For video input, conventional approaches used auto iris which is very poor in adaptation for sudden brightness change. Conventional methods for background generation do not yield good results in intersections with heave traffic and most of the early studies measure only point information. In this paper, we propose user-controlled iris method to remedy the deficiency of auto iris and design flame difference-based background generation method which performs far better in complicated intersections. We also propose measurement method for spatial traffic information such as interval volume/lime/velocity, queue length, and turning/forward traffic flow. We obtain measurement accuracy of 95%∼100% when applying above mentioned new methods.

• Journal of the Korean Society of Radiology
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• v.8 no.1
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• pp.19-26
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• 2014

This paper suggests techniques to enhance coding time which is a problem in traditional fractal compression and to improve fidelity of reconstructed images by determining fractal coefficient through adaptive selection of block approximation formula. First, to reduce coding time, we construct a linear list of domain blocks of which characteristics is given by their luminance and variance and then we control block searching time according to the first permissible threshold value. Next, when employing three-level block partition, if a range block of minimum partition level cannot find a domain block which has a satisfying approximation error, we choose new approximation coefficients using a non-linear approximation of luminance term. This boosts the fidelity. Our experiment employing the above methods shows enhancement in the coding time more than two times over traditional coding methods and shows improvement in PSNR value by about 1-3dB at the same compression rate.

• Journal of the Korean Society of Radiology
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• v.10 no.4
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• pp.263-270
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• 2016

This paper suggests techniques to enhance coding time which is a problem in traditional fractal compression and to improve fidelity of reconstructed images by determining fractal coefficient through adaptive selection of block approximation formula. First, to reduce coding time, we construct a linear list of domain blocks of which characteristics is given by their luminance and variance and then we control block searching time according to the first permissible threshold value. Next, when employing three-level block partition, if a range block of minimum partition level cannot find a domain block which has a satisfying approximation error, There applied to 24-bpp color image compression and image techniques. The result did not occur a loss in the image quality of the image when using the encoding method, such as almost to the color in the YIQ image compression rate and image quality, such as RGB images and showed good.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.4
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• pp.344-350
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• 2014

Multi Function Display(MFD) of Korean Utility Helicopter(KUH) is the component of mission management/display control system and displays image information(navigation, flight, survivability, digital map, maintenance) acquired from Mission Computer(MC) while the aircraft is operated. It is an essential equipment for pilots to perform flight mission and it has functions of display scene control, data display, built in test(BIT) and brightness control. In this paper, it is analyzed the cause of abnormal display(flickering) on MFD and summarized the design changes to solve the defect. It is also described system safety analysis and suggested verification results of flight/ground test.

• The Journal of Korean Institute of Information Technology
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• v.17 no.6
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• pp.9-16
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• 2019

Companies that want to improve their manufacturing processes have recently introduced the smart factory, which is particularly noticeable. The ultimate goal is to maximize the area of the smart factory that performs the process of the production facility completely with minimal manual control and to minimize errors of reasoning. This research is a part of a project for unmanned production, management, packaging, and delivery management and the detection of the start point of rebars to perform the automatic calibration of the rollers through the tracking of the automated facilities of unmanned production. It must meet the requirement to accurately track the position from the start point to the end point. In order to improve the tracking performance, it is important to set the accurate start point. However, the probability of tracking errors is high depending on environments such as illumination and dust through the conventional time-based detection method. In this paper, we propose a starting point detection method using the average brightness change of high speed IR camera to reduce the errors according to the environments, As a result, its performance is improved by more than 15%.

• Journal of the Microelectronics and Packaging Society
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• v.29 no.2
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• pp.121-127
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• 2022

Micro-LED is a light-emitting diode smaller than 100 ㎛ in size. It attracts much attention due to its superior performance, such as resolution, brightness, etc., and is considered for various applications like flexible display and VR/AR. Micro-LED display requires a mass transfer process to move micro-LED chips from a LED wafer to a target substrate. In this study, we proposed a vacuum chuck method as a mass transfer technique. The vacuum chuck was fabricated with MEMS technology and PDMS micro-mold process. The spin-coating approach using a dam structure successfully controlled the PDMS mold's thickness. The vacuum test using solder balls instead of micro-LED confirmed the vacuum chuck method as a mass transfer technique.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.10
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• pp.1-7
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• 2020

In recent years, as LED display systems are actively spread, study on effective control methods for an LED driver for driving the systems has been in progress. The most representative among them is the uniform brightness control method for the LED driver channel. In this paper, we propose an LED driver IC for BLU with current compensation and system protection functions to minimize channel luminance deviation. It is designed for current accuracy within ±3% between channels and a channel current of 150 mA. In order to satisfy the design specifications, the channel amplifier offset was canceled out by a chopping operation using a channel-driving PWM signal. Also, a pre-charge function was implemented to minimize the fast operation speed and luminance deviation between channels. LED error (open, short), switch TR short detection, and operating temperature protection circuits were designed to protect the IC and BLU systems. The proposed IC was fabricated using a Magnachip 0.35-um CMOS process and verified using Cadence and Synopsys' Design Tool. The fabricated LED driver IC has current accuracy within ±1.5% between channels and 150-mA channel output characteristics. The error detection circuits were verified by a test board.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.11
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• pp.205-210
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• 2014

This is concerned with the technology to display the design on Porcelain and adjust malfunction for moving effect and light intensity by curator. More precisely, the technology makes it possible that the porcelain is connected to Light module which is the device for controlling light emission and rotating rolling plate, etc that are connected to LED light module, optical fiber and controller that is for scenario from the given storytelling. In addition, with a WiFi portable device (Smart-phone, other mobile device). equipped with a scenario programs, information for operation, failure and malfunction can be obtained and analyzed in real-time, and menu color and alarm is alerted when the displaying design is in abnormal status, which makes the early reactions to the status. Furthermore, the collected data can be sent through WiFi network to the device and PC managed by the curator specialized in managing the design on the Porcelain, thus the technology could help the curator who have less knowledge about moving pattern on the Porcelain. There is always a possibility of malfunction due to various condition that are caused by wring-harness when modules are wired-connected. In this research, in order to overcome this problem, we propose a system configuration that can do monitoring and diagnosis with a device for collecting data from LED control module, Light emission sensor and a personal WiFi device. Also, we performed connection between optical Fiber and LED and interlock for the system defined by the definition for information and storytelling scenario.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.44 no.4 s.316
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• pp.60-69
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• 2007

The human eye usually experiences a loss of color sensitivity when it is subjected to high levels of luminance, and perceives a discrepancy in color between high and normal-luminance displays, generally known as a hue shift. Accordingly, this paper models the hue-shift phenomenon and proposes a hue-correction method to provide perceptual matching between high and normal-luminance displays. The value of hue-shift is determined by perceived hue matching experiments. At first the phenomenon is observed at three lightness levels, that is, the ratio of luminance is the same between high and normal-luminance display when the perceived hue matching experiments we performed. To quantify the hue-shift phenomenon for the whole hue angle, color patches with the same lightness are first created and equally spaced inside the hue angle. These patches are then displayed one-by-one on both displays with the ratio of luminance between two displays. Next, the hue value for each patch appearing on the high-luminance display is adjusted by observers until the perceived hue for the patches on both displays appears the same visually. After obtaining the hue-shift values, these values are fit piecewise to allow shifted-hue amounts to be approximately determined for arbitrary hue values of pixels in a high-luminance display and then used for correction. Essentially, input RGB values of an image is converted to CIELAB values, and then, LCh (lightness, chroma, and hue) values are calculated to obtain the hue values for all the pixels. These hue values are shifted according to the amount calculated by the functions of the hue-shift model. Finally, the corrected CIELAB values are calculated from corrected hue values, after that, output RGB values for all pixels are estimated. For evaluation, an observer's preference test was performed with hue-shift results and Almost observers conclude that the images from hue-shift model were visually matched with images on normal luminance display.

• Korean Journal of Optics and Photonics
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• v.24 no.5
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• pp.231-236
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• 2013

We investigated the optical design of a smart headlamp capable of producing various beam patterns through only on/off modulation of light sources. This was implemented by forming a continuous matrix of beams from discontinuous beam patterns by means of a multi-array LED optical system. As one such optical system, the multi-array LED system is a convenient and economical device for implementing beam patterns with the simple on/off modulation of the light sources. A single optical assembly module can be made by combining a multiple-LED array, optical system module, and electronic control with no need for any additional mechanical components. The present optical system was designed to include a secondary lens and a projection lens mounted at the front of each LED in the array to realize accurate lighting patterns as well as the required luminosity at a distance of 25 m in the forward direction. Finally, we identified and analyzed the patterns implemented by the designed optical system that produced satisfactory performance of high beams and adaptive driving beams (ADB).