• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.4B
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• pp.715-724
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• 2000

This Paper presents 3-D subband filter banks which are effective for progressive and lossless compression of volumetric images. For such a purpose, ORT(Overlapping Rounding Transform), applied so far to 1-D losslesssubband filter banks, is now used to implement two types of 3-D lossless subband filter banks: separable andnon-separable types. Separable fiter banks are implemented form applying 1-D lossless filter banks consecutively.Non-separable later banks are developed by expanding the 1-D ORT into 3-D one. In particular, the proposed ORT based 3-D non-separable filter banks generalizes the 3-D HINT(Hierarchical INTerpolation) algorithm.Through the experiment comparisons on various volumetric medical images, we prove that the proposedseparablefnon-separable filter banks perform better, in terms of compression ratio (first order entropy), than theother lossless compression techniques such as block based transform and conventional 3-D HINT.

• Proceedings of the KIEE Conference
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• 2008.04a
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• pp.105-106
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• 2008

영상을 이용한 물체인식은 컴퓨터 비젼분야의 주요한 관심분야중 하나이다. 이중 특정기반 물체인식은 영상이 가지고 있는 특징점을 이용하는 방법으로 입력영상과 물체에 대한 질의 영상의 특징점을 검출하고 매칭을 수행하여 물체를 인식하게 된다. 특징점은 스케일, 회전, 어파인 변화 등에 변하지 않는 특징을 가지고 있는 점을 말한다. 이러한 특징점을 구하기 위하여 사용하는 방범으로는 SIFT(Scale Invariant Feature Transform)가 있다. SIFT는 스케일, 회선, 어파인 변화에 우수한 성능을 보여주기는 하나 많은 연산으로 인하여 처리속도가 느리다는 단점이 존재한다. 이에 본 논문에서는 SIFT를 사용한 특징기반 물체인식에서 속도 개선 방법에 대하여 제안하였다. 제안한 방법을 사용하였을 경우 물체인식을 위한 특징점을 검출하고 매칭을 수행하는데 소모된 시간이 줄어드는 것을 실험을 통하여 확인 하였다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.1C
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• pp.92-101
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• 2004

This paper proposes a algorithm to extract the variety region (object) from video for the real-time encoding of MPEG-4 based. The previous object segmentation methods cannot used the videophone or videoconference required by real-time processing. It is difficult to transfer a video to real-time because it increased complexity for the operation of each pixel on the spatial segmentation and temporal segmentation method proposed by MPEG-4 Working Group. But algorithm proposed for this thesis not operates a pixel unit but operates a macro block unit. Thus this enables real-time transfer. But this algorithm cannot extract several object for a image using proposed algorithm as previous algorithm. On system constructed by encoder and decoder. A proposed algorithm inserted for encoder as pre-process.

• Journal of Biomedical Engineering Research
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• v.21 no.4
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• pp.433-439
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• 2000

Volume rendering is a powerful tool for visualizing sampled scalar values from 3D data without modeling geometric primitives to the data. The volume rendering can describe the surface-detail of a complex object. Owing to this characteristic. volume rendering has been used to visualize medical data. The size of volume data is usually too big to handle in real time. Recently, various volume rendering algorithms have been proposed in order to reduce the rendering time. However, most of the proposed algorithms are not proper for fast rendering of large non-coded volume data. In this paper, we propose a block-based fast volume rendering algorithm using a shear-warp factorization for non-coded volume data. The algorithm performs volume rendering by using the organ segmentation data as well as block-based 3D volume data, and increases the rendering speed for large non-coded volume data. The proposed algorithm is evaluated by rendering 3D X-ray CT body images and MR head images.

• Journal of Korea Multimedia Society
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• v.6 no.5
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• pp.805-815
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• 2003

In this paper, we present the development of document compression codec using segmentation, wavelet lifting and bitplane coding. We use the segmentation to preserve the text appearance. We performed integer-to-integer wavelet lifting and also performed bitplane subblock coding for document compression. We acquired a high compression ratio and an efficient compression by encoding only the significant subblocks in the bitplane subblock coding. We also implemented scalar quantization by subband-oriented bit shifting. The system performs color conversion and downsampling before wavelet lifting and also performs graycode conversion and quantization before subblock coding. In the experiment, we show the performances of the system by presenting the high compression ratios and high PSNR values.

• Journal of Broadcast Engineering
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• v.8 no.3
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• pp.297-305
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• 2003

In this paper, we propose a wavelet based fast motion estimation algorithm for video sequence encoding with very low bit-rate. By using one of properties oi wavelet transform, multi-resolution analysis(MRA) property and spatial Interpolation of an image, we are able to reduce both prediction error and computational complexity at the same time. Especially, by defining a significant block(SB) based on the differential information of wavelet coefficients between successive frames, the proposed algorithm makes up a defect of multi-resolution motion estimation(MRME) algorithm of increasing the number of motion vectors. As experimental results. we can reduce the computational load up to 70% but also improve PSNR up to about 0.1 ∼ 1.2 dB comparing with the MRME algorithm.

• Journal of Broadcast Engineering
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• v.7 no.1
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• pp.37-44
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• 2002

In this paper. we propose a new video coding scheme with multi-resolution motion compensation and residual quantization. The main functional blocks of the proposed scheme include multi-level wavelet decomposition. motion estimation and motion compensation. raster scanning within each subband. formation of block trees and blocking partitioning. and adaptive arithmetic coding. Although the proposed ceding scheme is simple and requires low computational complexity, it produces bitstreams tilth good features. such as the embedded structure and SNR scalability. Experimental results demonstrate that the proposed coding scheme is quote competitive to and often outperforms other wavelet-based video coding schemes in the literature.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2016.06a
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• pp.253-255
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• 2016

본 논문에서는 다중 지역 이진 패턴(Multi-scale Bock LBP, MB-LBP) 특징과 랜덤 포레스트에 기반한 새로운 기법의 머리 방향 분류 기법을 제안한다. 제안 기법에서는 occlusion 과 조명의 변화에 강인한 분류 정확도를 얻기 위해서 랜덤화된 트리를 학습하는 것을 목표로 한다. 우선, 얼굴 이미지로부터 많은 MB-LBP 특징을 추출하고, 얼굴 영상들을 랜덤하게 입력하고 MB-LBP 크기 파라미터와 같은 랜덤 특징과 블록 좌표들을 사용하여 트리를 생성한다. 게다가 각 노드에서 정보 이득을 최대화 하는 트리의 내부 노드를 생성하기 위해서 uniform LBP 의 특성을 고려한 분할 함수를 개발한다. 랜덤화된 트리는 랜덤 포레스트에 포함되어 있으며 마지막 결정단계에서 Maximum-A-Posteriori criterion 으로 최종 결정을 한다. 실험 결과는 제안 기법이 다양한 조명, 자세, 표현, occlusion 상황에서 기존의 방법보다 개선된 성능으로 머리 방향을 분류 할 수 있음을 보여준다.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.275-276
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• 2006

본 논문에서는 내용기반 영상검색을 보다 효과적인 알고리즘 설계를 위해 칼라 RGB 특징정보 추출에 median 필터링을 이용한 영상검색의 성능을 분석하였다. 칼라영상에서 각각의 R,G,B칼라영상으로 나눈 후 일정크기의 블록으로 분할하여 R,G,B 각각의 중간값을 추출하고 크기순과 레벨의 특징자를 이용한 영상검색 기법을 제안한다.

• The Transactions of the Korea Information Processing Society
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• v.7 no.5
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• pp.1587-1598
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• 2000

For the object-based video compression at very low bit rate, vieo segmentation is an essential part. In this paper, we propose a temporal video segmentation algorithms for motion pictures which is based on blocks. The algorithm is composed of three steps: (1) the change-detection, (2) the block merging, and (3) the block segmentation. The first step separates the change-detected region from background. Here, a new method for removing the uncovered region without motion estimation is presented. The second step, which is further divided into three substeps, estimates motions for the change-detected region and merges blocks with similar motions. The merging conditions for each substep as criteria are also given. The final step, the block segmentation, segments the boundary block that is excluded from the second step on a pixel basis. After describing our algorithm in detail, several experimental results along the processing order are shown step by step. The results demonstrate that the proposed algorithm removes the uncovered region effectively and produced objects that are segmented well.