• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.10
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• pp.1155-1166
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• 2016

In this paper, we propose a new embedded video compression scheme which uses three-dimensional rate-distortion optimization based block coder. After the proposed scheme removes temporal redundancy by applying the motion compensated temporal filtering(MCTF) on input video frames, two dimensional discrete wavelet transform is applied on video frames to remove spatial redundancy. The three-dimensional wavelet coefficients generated in this way are sorted according to their expected rate-distortion slope and encoded by using the three-dimensional block partition coding method. The proposed scheme also uses both the effective color video coding method which maintains embedded features, and the efficient bit-rate control method. Experimental results demonstrate that the proposed scheme not only produces embedded bit-streams, but also outperforms existing video compression schemes.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 1999.10a
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• pp.159-173
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• 1999

본 논문은 교차로에 설치된 영상검지기로부터 들어온 교통정보 중 공간교통정보에 해당하는 차량 대기길이를 측정을 하는 방법으로 각 차선(lane)별 검지영역에 대하여 웨이브렛 변형(Wavelet Transforms)을 하여 차량을 검지하고, 검지영역 내에서 차량의 대기길이를 측정하는 알고리즘을 제안한다. 기존의 방법으로는 차량 윤곽선 추출(edge detection)을 이용한 대기길이 측정 방법이나 배경(background)정보를 사전에 입수한 후 임계값 이상의 변화가 있을 때 차량을 검지하여 대기길이를 측정하는 방법 등이 연구되어 왔으나 이러한 방법들은 영상의 노이즈에 대하여 크게 영향을 받는다는 문제점이 있다. 그러나 본 알고리즘은 영상의 노이즈에 대하여 크게 영향을 받지 않을 뿐만 아니라 시간대 변화에 따른 도로의 명암값(intensity or gray level)을 추정할 필요가 없다는 특징이 있다. 특히, 야간 영상인 경우 차량 헤드라이트로 인한 검지오류도 감소할 수가 있다. 본 논문에서 실험은 주간, 야간 각각 1개 차선의 80개 표본크기로 실험을 하였으며, 대기길이는 정지 대기길이(standing queue length)와 이동 대기길이(moving queue length)로 나누어 측정을 하였다. 그 결과 주간, 야간의 경우 정지 대기길이는 2.14%, 2.24%, 이동 대기길이는 2.59%, 2.74%의 오차율로 측정이 되었다.

• Proceedings of the IEEK Conference
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• 2001.06c
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• pp.73-76
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• 2001

We propose a new method for image coding that it is based on highly related property between a spatial image and wavelet transform image. The characteristics have an important role in the design of proposed algorithm. This algorithm for image coding is to obtain high compression rate at low bit rate. The other side, the high activity regions are related to significant coefficients which give much influence to image reconstruction, because they mean the important factor to represent the appearance of images such as edge or boundary. For some images with low activity, we can obtain the reconstructed image with near to 30 dB at 150: 1 compression ratio.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.33B no.11
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• pp.62-71
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• 1996

In this paper we propose a method that improves PSNR at low bit rate and reduces computational complexity in fractal image coding based on discrete wavelet transform. The proposed method, which uses significant coefficient tree, improves PSNR of the reconstructed image and reduces computational comlexity of mapping domain block onto range block by matching only the significant coefficients of range block to coefficients of domain block. Also, the proposed method reduces error propagation form lower resolution subbands to higher resolution subbands by correcting error of lower resolution subbands. Some experimental results confirm that the proposed method reduces encoding and decoding time significantly and has fine reconstructed images having no blocking effect and clear edges at low bit rate.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.51 no.5
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• pp.247-254
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• 2002

This paper describes a fault location algorithm in real combined transmission systems with underground power cable. The algorithm to calculate the fault location was developed using DWT wavelet transform and travelling wave occurred at fault point. And the proposed algorithm is also used the transient signal of one end in stead of the signal information of two ends. On the other hand, in this papers, the method to discriminate fault point between overhead line and cable section is also Proposed. Variety simulations were carried out to verify the accuracy and effectiveness of the proposed algorithm using EMTP/ATFDraw and Matlab. Simulation results show that the proposed method has the excellent ability for discrimination of fault section and fault location in combined transmission systems with power cables.

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.959-962
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• 1998

In this paper, we propose an efficient vehicle detection and classification algorithm for an electronic toll collection, which is based on shadow robust vehicle presence test. In order to improve the performance of vehicle presence test, we use correlation coefficients between wavelet transformed input and reference images, which takes advanage of textural similarity. We compare the performance of the vehicle presence test with those of some conventional approaches that use variance of frame difference. Experimental results from field test show that the proposed vehicl detection and classification algorithm performs well even under abrupt intensity change due to the characteristics of sensor and occurrence of shadow.

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.1101-1104
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• 1998

The modern multimedia applications which are video processor, video conference or video phone and so forth require real time processing. Because of a large amount of image data, those require high compression performance. In this paper, the prosposed image processing encoder was designed by using wavelet transform encoding. The proposed filter block can process imae data on the high speed because of composing individual function blocks by parallel and compute both highpass and lowpass coefficient in the same clock cycle. When image data is decomposed into multiresolution, the proposed scheme needs external memory and controller to save intermediate results and it can operate within 33MHz.

• Proceedings of the IEEK Conference
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• 2000.06c
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• pp.113-116
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• 2000

In this paper, we present new scheme for image coding which efficiently use the relationship between the properties of spatial image and its wavelet transform. Firstly an original image is decomposed into several layers by the wavelet transform, and simultaneously decomposed into 2$\^$n/ ${\times}$ 2$\^$n/ blocks. Each block is classified into 3 regions according to their property, i.e., low activity region(LAR), midrange activity region(MAR), high activity region(HAR). Secondly we are applied texture modeling technique to LAR, MAR and HAR are encoded by Stack-Run coding technique. Finally our scheme Is superior to the Zerotree method in both reconstructed image Quality and transmitted bit rates.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.211-214
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• 2002

The detection of tool wear is very important in an automated manufacturing system. This paper presents a tool condition monitoring system based on the wavelet transform analysis of the AC servo motor current in a milling process. The current measurement is relatively simple and does not affect machining operations. The discrete wavelet transform was used to decompose the current of a spindle AC servo motor in the time and frequency domain. The feature vectors were extracted from the decomposed signals and compared to clarity normal and wear conditions. The results show the feasibility of the wavelet transform analysis for the tool condition monitoring.

• Proceedings of the KAIS Fall Conference
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• 2009.12a
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• pp.961-964
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• 2009

본 논문은 복합재료로부터 얻어진 C-scan영상에서의 효과적인 잡음 제거에 관한 연구 내용이다. 복합재료에서의 결함을 검출하는 것은 여러 실용, 응용분야에서 관심을 가지는 주제이다. 초음파 영상은 대부분이 육안으로 정확한 판단을 하기에는 어렵고, 잡음의 영향으로 정확한 결함에 대한 영역을 파악하는데 문제를 발생시킨다. 결함의 정확한 판별을 위해서는 물체의 영역을 정확히 판별하는 것이 중요하지만 영상에서 잡음에 대한 문제를 우선 해결해야 한다. C-scan 영상에서의 배경과 결함의 경계영역을 보존하면서 잡음 제거를 위해 웨이브렛(Wavelet) 변환을 이용하는 방법을 제안한다. 특히, C-scan 영상에서 Filtering을 적용하는데에 있어 드비시(Daubechies) Wavelet Filtering이 결함영역에 대한 좀 더 명확한 분석이 가능하게 함을 얘기하고자 한다.