• Journal of Internet Computing and Services
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• v.10 no.1
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• pp.75-82
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• 2009

In this paper, we propose a robust preprocessing scheme for entropy coding in gray-level image. The issue of this paper is to reduce additional information needed when bit stream is transmitted. The proposed scheme uses the preprocessing method of co-occurrence count about gray-levels in neighboring pixels. That is, gray-levels are substituted by their ranked numbers without additional information. From the results of computer simulation, it is verified that the proposed scheme could be reduced the compression bit rate by up to 44.1%, 37.5% comparing to the entropy coding and conventional preprocessing scheme respectively. So our scheme can be successfully applied to the application areas that require of losslessness and data compaction.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.11
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• pp.97-104
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• 2004

This paper proposes an efficient VLSI architecture of 9-7/5-3 Lifting DWT filters that is used by lossy or lossless compression of JPEG2000. The proposed architecture uses only internal line memories to compute Lifting-DWT operations and its PE(Processing Element) has critical path with 1 multiplier and 1 adder. To reduce the number of PE, we make the vertical filter that is responsible for the column operations of the first level perform both the row and column operations of the second and following levels. As a result, the architecture has smaller hardware cost compared to that of other architectures. It was modeled in RTL level using VHDL and implemented on Altera APEX 20K FPGA.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.49 no.3
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• pp.62-68
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• 2012

In this paper, we propose an efficient transmission scheme for flight data. It is important to reduce amount of flight data transmitted effectively for timely transmission in airplane that the safety is very importantly recognized. Thus, this paper shows the improved technique transmitting after compressing flight data by the lossless compression technique. Because the proposed method improves the transmission speed of the flight data effectively. The processing of flight data and handling can be easily performed in the time to be restricted. The simulation results show that the proposed scheme achieves 25% data transfer gain compared to the ARINC 429 based transmission method.

• The Journal of the Korea Contents Association
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• v.2 no.4
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• pp.23-29
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• 2002

This paper suggest the image compression that is needed to process PACS in medical information system. The image decoding method is used Linear-predictor and Lloyd-Max quantizer(quantization) in the Wavelet transform domain. Wavelet Transform Method is processed the multi-resolution by dividing image into 10 sub-bands of 3 levels. Low frequency domain that is sensitive to human visual characteristic is encoded by DPCM which is lossless encoding methods, and Lloyed-Max quantizer, the optimal quantizer for reducing ringing and aliasing in the image of inter sub-band, is used in the remaining high frequency domain of sub-band. The examination verifies that decompressed images are superior by the result that PSNR is 28.53dB on the input image, 512$\times$152 abdominal CT image and Chest image.

• Journal of the Institute of Convergence Signal Processing
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• v.1 no.1
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• pp.82-88
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• 2000

In this paper, We compare the Harr wavelet of the S+P transform with various integer coefficient filter banks and apply 9/7 ICFB to the wavelet transform. In addition, we propose a entropy-coding method that exploits the multiresolution structure and the feedback of the prediction error, and can efficiently compress the transformed image for progressive transmission. Simulation results are included to compare to the compression ratio using the S+P transform with different types of images.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.6
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• pp.1482-1489
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• 1998

This paper aims to extract characteristics of the spectrum of fingerprint image and to apply them to image enhancement techniques in spatial frequency domain. Based on 1$\times$64 window as a processing unit and the different record lengths(32, 16, 8), the estimate of power spectrum density for each length was made. Each acquired spectrum characteristics was applied to the re-synthesis process of the fingerprint image, an improved gray scale image was obtained. In order to select an optimal predictor and the Huffman table for the fingerprint iamge, the lossless JPEG algorithm was used. Experiments were performed for extracting distribution characteristics for the each of 7 predictors from the fingerprint image and modeling processes, and the result was applied to the data compression algorithm and the selection of the optimal predictor.

• Journal of the Korean Institute of Intelligent Systems
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• v.23 no.6
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• pp.519-526
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• 2013

ECG signal has the feature that is repeated in a cycle of P, Q, R, S, and T waves and is sampled at a high sampling frequency in general. By using the feature of periodic ECG signals, maximizing compression efficiency while minimizing the loss of important information for diagnosis is required. However, the periodic characteristics of such amplitude and period is not constant by measuring time and patients. Even though measured at the same time, the patient's characteristics display different periodic intervals. In this paper, an adaptive multi-level coding is provided by coding adaptively the dominant and non-dominant signal interval of the ECG signal. The proposed method can maximize the compression efficiency by using a multi-level code that applies different compression ratios considering information loss associated with the dominant signal intervals and non-dominant signal intervals. For the case of long time measurement, this method has a merit of maximizing compression ratio compared with existing compression methods that do not use the periodicity of the ECG signal and for the lossless compression coding of non-dominant signal intervals, the method has an advantage that can be stored without loss of information. The effectiveness of the ECG signal compression is proved throughout the experiment on ECG signal of MIT-BIH arrhythmia database.

• Journal of Internet Computing and Services
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• v.23 no.1
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• pp.31-38
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• 2022

An electrocardiogram(ECG) is a recoding of electrical signals of the heart's cyclic activity and an important body information for diagnosing myocardial rhythm. Large amount of information are generated continuously and a significant period of cumulative signal is required for the purpose of diagnosing a specific disease. Therefore, research on compression including clinically acceptable lossy technique has been developed to reduce the amount of information significantly. Recently, wearable smart heart monitoring devices that can transmit electrocardiogram(ECG) are being developed. The use of electrocardiogram, an important personal information for healthcare service, is rapidly increasing. However, devices generally have limited capability and power consumption for user convenience, and it is often difficult to apply the existing compression method directly. It is essential to develop techniques that can process and transmit a large volume of signals in limited resources. A method for compressing and transmitting the ECG signals efficiently by using the cumulative average (template) of the unit waveform is proposed in the paper. The ECG is coded lovelessly using template matching. It is analyzed that the proposed method is superior to the existing compression methods at high compression ratio, and its complexity is not relatively high. And it is also possible to apply compression methods to template matching values.

• Proceedings of the KIEE Conference
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• 2008.04a
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• pp.107-108
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• 2008

본 논문에서는 8-bits의 그레이레벨 영상에서 그레이레벨(gray-level) 값들의 발생 빈도(frequency)에 따른 순위 변환(Ranking-Transformation)을 이용한 효율적인 무손실 압축을 제안한다. 제안한 기법은 서로 인접한 픽셀의 그레이레벨의 쌍에 대한 발생 빈도를 토대로 원 영상의 그레이레벨 값을 이에 대응하는 순위 값으로 변환시킨다. 이때 부가정보가 발생하지 않도록 입력영상의 픽셀들에 대하여 한 픽셀씩 순차적으로 지정한 순위로 재구성한다. 실험결과, 부가 정보 없이 입력 영상을 압축하게 되어 엔트로피 부호화기를 통한 디지털 영상들의 효율적인 압축 성능 향상을 기대할 수 있다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.11a
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• pp.107-110
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• 2009

본 논문에서는 무손실 위성 영상 압축의 효율을 높이기 위해 H.264/AVC의 무손실 화면내 부호화에 기반한 새로운 문맥기반 적응적 가변 길이 부호화 (CAVLC) 방법을 제안한다. 기존의 H.264/AVC의 CAVLC는 손실 압축에 적합하게 설계되었기 때문에, 변환과 양자화 과정을 수행하지 않는 무손실 압축에서 최적의 압축 성능을 제공하지 못한다. 본 논문에서는 손실 압축과 무손실 압축 환경에서 잔여 영상 신호의 통계적 차이가 있음을 확인하고, 무손실 위성 영상 압축 환경에서 잔여 신호의 통계적 특성을 고려하여 향상된 CAVLC 기반의 무손실 위성 영상 압축 방법을 제안한다. 제안한 방법을 사용하여 위성 영상을 압축한 결과 기존의 대표적인 무손실 영상 압축 방법인 JPEG-LS와 CALIC 보다 약 12% 정도 비트 수를 감소시켰다.