• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.143-146
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• 2008

Dynamic range of LCD panel can be dramatically improved by adaptive dimming technique. Adaptive control of LED backlight by input signal can reduce the light leakage of LCD panel and achieve high contrast ratio. An algorithm is proposed to distinguish the input signal and get proper luminance level. For lower cost of LCD panel, white light LED is used to accomplish 2D dimming and get better image performance of LCD.

• Journal of the Korean Institute of Telematics and Electronics
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• v.24 no.5
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• pp.841-848
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• 1987

This paper presents a new two-stage edge detection algorithm which can give thin edges and can find edges between low contrast regions. In the first stage, the potential edge points are obtained using the proposed edge operator which is motivated by the concept of the E filter. And in the second stage, the real edge points adre detected by comparing the potential edge values with the lically adaptive threshold values of the corresponding potential edge points and by testing whether the potential edge points are zero-crossing points or not. It is shown quantitatively that the proposed algorithm can find edges effectively in an image with impulse noise, and also the results of applying the proposed algorithm to real images are presented.

• Proceedings of the IEEK Conference
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• 2000.07b
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• pp.843-846
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• 2000

An optical flow-based motion estimation algorithm is proposed for video coding. The algorithm uses block-matching motion estimation with an adaptive search region. The search region is computed from motion fields that are estimated based on the optical flow. The algorithm is based on the fact that true block-motion vectors have similar characteristics to optical flow vectors. Thereafter, the search region is computed using these optical flow vectors that include spatial relationships. In conventional block matching, the search region is fixed. In contrast, in the new method, the appropriate size and location of the search region are both decided by the proposed algorithm. The results obtained using test images show that the proposed algorithm can produce a significant improvement compared with previous block-matching algorithms.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.40 no.4
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• pp.374-381
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• 1991

As a diagnostic image of hospitl, the utilization of digital image is steadily increasing. Image coding is indispensable for storing and compressing an enormous amount of diagnostic images economically and effectively. In this paper adaptive two stage vector quantization based on Kohonen's neural network for the compression of cardioangiography among typical angiography of radiographic image sequences is presented and the performance of the coding scheme is compare and gone over. In an attempt to exploit the known characteristics of changes in cardioangiography, relatively large blocks of image are quantized in the first stage and in the next stage the bloks subdivided by the threshold of quantization error are vector quantized employing the neural network of frequency sensitive competitive learning. The scheme is employed because the change produced in cardioangiography is due to such two types of motion as a heart itself and body motion, and a contrast dye material injected. Computer simulation shows that the good reproduction of images can be obtained at a bit rate of 0.78 bits/pixel.

• Journal of information and communication convergence engineering
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• v.20 no.3
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• pp.153-159
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• 2022

Plain radiographic analysis is the initial imaging modality for suspected small bowel obstruction. Among the many features that affect the diagnosis of small bowel obstruction (SBO), the presence of gas-filled or fluid-filled small bowel loops is the most salient feature that can be automatized by computer vision algorithms. In this study, we compare three frequently applied pixel-clustering algorithms for extracting gas-filled areas without human intervention. In a comparison involving 40 suspected SBO cases, the Possibilistic C-Means and Fuzzy C-Means algorithms exhibited initialization-sensitivity problems and difficulties coping with low intensity contrast, achieving low 72.5% and 85% success rates in extraction. The Adaptive Resonance Theory 2 algorithm is the most suitable algorithm for gas-filled region detection, achieving a 100% success rate on 40 tested images, largely owing to its dynamic control of the number of clusters.

• Proceedings of the Korea Information Processing Society Conference
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• 2001.04b
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• pp.867-870
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• 2001

본 논문에서는 디스플레이상에서 영상 향상을 위한 다계조 콘트라스트 조절장치를 제안하였다. 제안한 방식은 추가적인 메모리를 필요하지 않고, 입력 계조 레벨에 상관없이 영상향상이 가능하다. 또한 입력 영상의 자기 정보를 고려하여 원화상의 밝기정보를 최대한 보상할 수 있으며 기존의 방식에 비해 하드웨어 구성이 간단하여 실시간 처리를 요하는 분야에 쉽게 적용 가능하고 입력되는 콘트라스 영역의 가중치 값을 사용자가 임의적으로 변화시킴으로써 콘트라스트 조정이 가능하다. 제안한 콘트라스트 조정장치는 컴퓨터 시뮬레이션을 통하여 검증하였으며, 시뮬레이션 결과 영상 향상을 확인하였다.

• Journal of Biomedical Engineering Research
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• v.26 no.3
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• pp.171-176
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• 2005

This paper proposes an automatic liver segmentation method using improved partial histogram threshold (PHT) algorithms. This method removes neighboring abdominal organs regardless of random pixel variation of contrast enhanced CT images. Adaptive multi-modal threshold is first performed to extract a region of interest (ROI). A left PHT (LPHT) algorithm is processed to remove the pancreas, spleen, and left kidney. Then a right PHT (RPHT) algorithm is performed for eliminating the right kidney from the ROI. Finally, binary morphological filtering is processed for removing of unnecessary objects and smoothing of the ROI boundary. Ten CT slices of six patients (60 slices) were selected to evaluate the proposed method. As evaluation measures, an average normalized area and area error rate were used. From the experimental results, the proposed automatic liver segmentation method has strong similarity performance as the MSM by medical Doctor.

• Proceedings of the KIEE Conference
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• 2003.11c
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• pp.400-403
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• 2003

This paper presents the signal processing of the panoramic thermal warning system that detects the small target such as aircraft and helicopter from afar. We develope the all round looking thermal imaging system which can scan all the way. This system acquires the panoramic images to reconstruct the IR images by revolving head of sensor typed line sensor at high speed. For detection, where the object of interest may be small, it is sometimes difficult to specify from object and background by conventional contrast enhancement methods. Therefore we use the adaptive plateau equalization algorithm each region to improve the contrast and make the hardware system which consists of the signal processing board for real-time display. We can verify the proposed method by the computer simulation and the hardware implementation.

• Smart Structures and Systems
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• v.18 no.6
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• pp.1251-1267
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• 2016

In this paper, Simple Adaptive Control (SAC) is used to enhance the seismic response of nonlinear tall buildings based on acceleration feedback. Semi-active MR dampers are employed as control actuator due to their reliability and well-known dynamic models. Acceleration feedback is used because of availability, cost-efficiency and reliable measurements of acceleration sensors. However, using acceleration feedback in the control loop causes the structure not to apparently meet some requirements of the SAC algorithm. In addition to defining an appropriate SAC reference model and using inherently stable MR dampers, a modification in the original structure of the SAC is proposed in order to improve its adaptability to the situation in which the plant does not satisfy the algorithm's stability requirements. To investigate the performance of the developed control system, a numerical study is conducted on the benchmark 20-story nonlinear building and the responses of the SAC-controlled structure are compared to an $H_2/LQG$ clipped-optimal controller under the effect of different seismic excitations. As indicated by the results, SAC controller effectively reduces the story drifts and hence the seismically-induced damage throughout the structural members despite its simplicity, independence of structural parameters and while using fewer number of dampers in contrast with the $H_2/LQG$ clipped-optimal controller.

• Journal of KIISE:Computer Systems and Theory
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• v.33 no.11
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• pp.810-819
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• 2006

This paper proposes an Adaptive Double Buffer Model. As a new FIFO buffer model, this technique minimizes packet losses from network congestion by logically managing buffers. It allocates the spare spaces of non-congested buffers to congested buffers by allowing receive/send buffers to share two queues, and hence it minimizes packet losses. In contrast to the buffer model utilizing a free list, this buffer model can prevent the bubble phenomenon caused by a memory leak and thereby apply to a network buffer in a restricted environment. Also, compared with the model using an way, this model brings maximum 100 percent improvement in accepting packets and compared with the model utilizing a free list, this model has the similar efficiency Results of the performance test on Adaptive Double Buffer Model, shows that this proposed model decreases packet losses and enhances memory efficiency.