• Title/Summary/Keyword: Visual block

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Adaptive subband vector quantization using motion vector (움직임 벡터를 이용한 적응적 부대역 벡터 양자화)

  • 이성학;이법기;이경환;김덕규
    • Proceedings of the IEEK Conference
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    • 1998.06a
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    • pp.677-680
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    • 1998
  • In this paper, we proposed a lwo bit rate subband coding with adaptive vector quantization using the correlation between motion vector and block energy in subband. In this method, the difference between the input signal and the motion compensated interframe prediction signal is decomposed into several narrow bands using quadrature mirror filter (QMF) structure. The subband signals are then quantized by adaptive vector quantizers. In the codebook generating process, each classified region closer to the block value in the same region after the classification of region by the magnitude of motion vector and the variance values of subband block. Because codebook is genrated considering energy distribution of each region classified by motion vector and variance of subband block, this technique gives a very good visual quality at low bit rate coding.

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Study of Block-formed Retaining Wall for Reducing Construction Waste

  • Kim, Chun-Ho
    • Journal of Environmental Science International
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    • v.11 no.11
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    • pp.1183-1187
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    • 2002
  • Existing retaining walls are usually made from only one cast form and any damage must be promptly repaired. However, when a part of a retaining wall is repaired, a gap can be created between the repaired and existing parts, along with an unpleasing visual effect. As such, the whole structure is often reconstructed, rather than repairing one part, resulting in construction waste and possible contamination of the environment. Accordingly, the current study proposes a construction method for a retaining wall that uses separate blocks to downsize of quantity of construction waste. In addition, by changing the color or modifying the block cover a more environmentally friendly retaining wall construction method is achieved.

Error Concealment based on Extended Block Matching using Gradient Difference (그래디언트 차를 이용한 확장된 블록매칭 기반의 에러은폐기법)

  • 김동욱;김진태
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.28 no.2C
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    • pp.201-208
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    • 2003
  • The error concealment is very useful technique for real-time communication, such as video conference. In this paper. we propose the error concealment technique to minimize discontinuity of block boundary in consideration of the fact that human visual system is sensitive to discontinuity. The error concealment for each loss block is performed by extended block matching method based on gradient difference. In the simulation result, performance improvement for the proposed technique is on the average 1.32㏈ in comparison with the conventional technique.

Automatic Registration between EO and IR Images of KOMPSAT-3A Using Block-based Image Matching

  • Kang, Hyungseok
    • Korean Journal of Remote Sensing
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    • v.36 no.4
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    • pp.545-555
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    • 2020
  • This paper focuses on automatic image registration between EO (Electro-Optical) and IR (InfraRed) satellite images with different spectral properties using block-based approach and simple preprocessing technique to enhance the performance of feature matching. If unpreprocessed EO and IR images from Kompsat-3A satellite were applied to local feature matching algorithms(Scale Invariant Feature Transform, Speed-Up Robust Feature, etc.), image registration algorithm generally failed because of few detected feature points or mismatched pairs despite of many detected feature points. In this paper, we proposed a new image registration method which improved the performance of feature matching with block-based registration process on 9-divided image and pre-processing technique based on adaptive histogram equalization. The proposed method showed better performance than without our proposed technique on visual inspection and I-RMSE. This study can be used for automatic image registration between various images acquired from different sensors.

Color Image Digital Watermarking Using Block Information (블록 정보를 이용한 칼라 정지영상 워터마킹)

  • 김희수;이호영;이호근;하영호
    • Proceedings of the IEEK Conference
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    • 2001.06d
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    • pp.81-84
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    • 2001
  • In this paper, we proposed a digital watermarking for color still image using the characteristics of human visual system and the achromatic block information. We use a binary watermark signal and insert watermark signal in the chromatic component region of YCrCb color space. In order to extract the watermark signal, we extracted the watermark signal by presuming that modified pattern of chromatic saturation without using original an image. Experimental results show that the proposed watermarking method has a good performance to embed watermark signal and extract one.

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Retinotopy of human visual cortex; A Study with 3T fMRI

  • 윤효운;정관진;임동미;조은미;송명성;연은경;박현욱
    • Proceedings of the KSMRM Conference
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    • 2002.11a
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    • pp.109-109
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    • 2002
  • Purpose: The aim of the study is to see the representation patterns of human visual cortex by perceiving some geometrical shapes. Method: 3 humans as subjects for the fMRI experiment. A classical block or box car design was used as experimental paradigm. 3 different types of fan shapes and concentric circles were presented.

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A meta-analysis on advantages of peripheral nerve block post-total knee arthroplasty

  • You, Di;Qin, Lu;Li, Kai;Li, Di;Zhao, Guoqing;Li, Longyun
    • The Korean Journal of Pain
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    • v.34 no.3
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    • pp.271-287
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    • 2021
  • Background: Postoperative pain management is crucial for patients undergoing total knee arthroplasty (TKA). There have been many recent clinical trials on post-TKA peripheral nerve block; however, they have reported inconsistent findings. In this meta-analysis, we aimed to comprehensively analyze studies on post-TKA analgesia to provide evidence-based clinical suggestions. Methods: We performed a computer-based query of PubMed, Embase, the Cochrane Library, and the Web of Science to retrieve related articles using neurothe following search terms: nerve block, nerve blockade, chemodenervation, chemical neurolysis, peridural block, epidural anesthesia, extradural anesthesia, total knee arthroplasty, total knee replacement, partial knee replacement, and others. After quality evaluation and data extraction, we analyzed the complications, visual analogue scale (VAS) score, patient satisfaction, perioperative opioid dosage, and rehabilitation indices. Evidence was rated using the Grading of Recommendations Assessment, Development, and Evaluation approach. Results: We included 16 randomized controlled trials involving 981 patients (511 receiving peripheral nerve block and 470 receiving epidural block) in the final analysis. Compared with an epidural block, a peripheral nerve block significantly reduced complications. There were no significant between-group differences in the postoperative VAS score, patient satisfaction, perioperative opioid dosage, and rehabilitation indices. Conclusions: Our findings demonstrate that the peripheral nerve block is superior to the epidural block in reducing complications without compromising the analgesic effect and patient satisfaction. Therefore, a peripheral nerve block is a safe and effective postoperative analgesic method with encouraging clinical prospects.

Post-processing Technique based on POCS for visual Enhancement (POCS를 이용한 효과적인 블록 현상 제거 기법)

  • Kim, Yoon;Jung, Jae-Han;Kim, Jae-Won;Ko, Sung-Jea
    • Proceedings of the IEEK Conference
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    • 2001.09a
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    • pp.755-758
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    • 2001
  • In this paper. Ive propose a postprocessing technique based on the theory of projection on convex sets(POCS) to reduce the blocking artifacts in HDTV decoded images. In BDCT of HDTV. the image is divided into a grid of non-overlapped 8 ${\times}$ 8 blocks. and then each block is coded separately. A block which is located one pixel apart from the grid of BDCT will include the boundary of the original 8 ${\times}$ 8 block. If the blocking artifact is Introduced alone the block boundary. this block will have different frequency characteristic from that of the original block. Thus, a comparison of frequency characteristics of these two overlapping blocks can detect the undesired high-frequency components mainly caused by the blocking artifact. By eliminating these undesired high-frequency components adaptively, robust smoothing projection operator can be obtained. Simulation results with real image sequences indicate that the proposed method performs better than conventional algorithms.

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Effect of treatment with S.O.T block on musculoskeletal pain caused by Traffic Accident (교통사고 환자를 대상으로 한 S.O.T block의 치료 효과)

  • Liu, Chi-Cheng;Oh, Min-Seok
    • Journal of Haehwa Medicine
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    • v.20 no.1
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    • pp.127-135
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    • 2011
  • Objectives : The purpose of this study was to investigate the effect of treatment with Sacro-Occipital Technique block on musculoskeletal pain caused by traffic accident by analysis of the Visual Analogue Scale(VAS), Neck Disability Index(NDI), Pain Disability Index(PDI), Oswestry Low back Pain Disability Index(ODI) and Short Form - McGill Pain Qusetionnaire (SF-MPQ). Methods : This study carried out on 18 patients who have received hospital treatment in Daejeon Univ. Dun-San Oriental Hospital. Control group got acupunture-therapy, herbal medication, physical therapy and Experimental group got all the therapies and treatment with Sacro-Occipital Technique block. We measured VAS, NDI, PDI, ODI and SF-MPQ on 1st day and 7 days later. Results : After being treated by our methods, Both group were improved in VAS, NDI, PDI, ODI, and SF-MPQ. Especially, Experimental group was significantly meaningful improved in VAS, PDI, and ODI. Control group was significantly meaningful improved in VAS and SF-MPQ. But, differences between control and experimental group were nonsignificant. Conclusions : The results suggest that treatment with Sacro-Occipital Technique block is not significantly meaningful but gives a positive impact on musculoskeletal pain caused by traffic accident. But further long term study in a large scale is needed.

Performance Comparison of BCS-SPL Techniques Against a Variety of Restoring Block Sizes (복원 블록 크기 변화에 따른 BCS-SPL기법의 이미지 복원 성능 비교)

  • Ryu, Joong-seon;Kim, Jin-soo
    • Journal of Korea Society of Industrial Information Systems
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    • v.21 no.3
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    • pp.21-28
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    • 2016
  • Compressed sensing is a signal processing technique for efficiently acquiring and reconstructing in an under-sampled (i.e., under Nyquist rate) representation. Specially, a block compressed sensing with Smoothed Projected Landweber (BCS-SPL) framework is one of the most widely used schemes. Currently, a variety of BCS-SPL schemes have been actively studied. However, when restoring, block sizes have effects on the reconstructed visual qualities, and in this paper, both a basic scheme of BCS-SPL and several modified schemes of BCS-SPL with structured measurement matrix are analyzed for the effects of the block sizes on the performances of reconstructed image qualities. Through several experiments, it is shown that a basic scheme of BCS-SPL provides superior performance in block size 4.