• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.9
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• pp.1032-1041
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• 2004

In this study we decompose the 3-dimensional velocity field of isotropic turbulent flow into the coherent and the incoherent structure using the discrete wavelet. It is shown that the coherent structure, 3% wavelet modes, has 98% energy and 88% enstrophy and its statistical characteristics are almost same as the original turbulence structure. And it is confirmed that the role of the coherent structure is that it produces the turbulent kinetic energy at the inertia range then transfers energy to the dissipation range. The incoherent structure, with residual wavelet modes, is uncorrelated and has the Gaussian probability density function but it dissipates the kinetic energy in dissipation range. On the procedure, we propose a new but easy way to get the threshold by applying the energy partition percentage concept about coherent structure. The vorticity field extracted from the wavelet-decomposed velocity field has the same structure as the result of the precedent studies which decomposed vorticity field directly using wavelet. Therefore it has been shown that velocity and vorticity field are on the interactive condition.

• Journal of IKEEE
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• v.6 no.1 s.10
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• pp.80-86
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• 2002

This paper presents a fast hardware architecture to implement a 2-D DWT(Discrete Wavelet Transform) computed by lifting scheme framework. The conventional 2-D DWT hardware architecture has problem in internal memory, hardware resource, and latency. The proposed architecture was based on the 4-way partitioned data set. This architecture is configured with a pipelining parallel architecture for 4-way partitioning method. Due to the use of this architecture, total latency was improved by 50%, and memory size was reduced by using lifting scheme.

• Journal of the Korean Society of Clothing and Textiles
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• v.26 no.2
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• pp.355-363
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• 2002

The purpose of this study was to investigate how the weave type, yarn twist fabric count and fiber content of the worsted fabrics affect the subjective sensation of the hand. Thirty worsted fabrics that were mainly used for the spring and fall ladies'suits at national brands were selected. Variables were such as four different kinds of weave types, plain, twill, satin and decorative; two levels of yarn twist, normal and high; various fabric counts; two different fiber contents, pure wool and Lycra contained. Image analysis and wavelet transform techniques were used to quantify the surface fiber, For surface characteristics, MIU, MMD and SMD were measured by KES-FB system. The Questionnaires with 23 adjectives were used for the subjective hand evaluation. Panels were So specialists of fashion or fabric designers and merchandizers. By Factor Analysis, six factors that represent the subjective hand were extracted. The relationship between these factors and structural variables were analyzed. Yarn twist was significantly related to the surface characteristics and resilience. Weave structure affected surface characteristics, volume/warm-cool feeling and resilience. Fabric counts showed relations with volume/warm-cool feeling and the fiber contents with volume/warm-cool feeling, resilience and elastic properties. MIU, MMD and SMD showed no relations with the surface fibers. Subjective sensation of surface characteristics was affected by SMD and surface fibers.

• Proceedings of the Korea Contents Association Conference
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• 2005.11a
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• pp.181-185
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• 2005

In this paper, the DWT(Discrete Wavelet Transform) based watermarking method for authentication and detection of image modification was proposed. The proposed algorithm inserts watermark into high frequency domain after 1-level wavelet transform by exchanging wavelet coefficients and embeds the characteristic values of high frequency domain of original image into the LSB part of watermarked image. Therefore, By extracting LSB values and watermark in the high frequency domain from the watermarked image, we can authenticate the image and detect modified positions.

• Proceedings of the Korea Contents Association Conference
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• 2005.11a
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• pp.480-484
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• 2005

In this paper, the multiwatermarking method to make it possible to the authentication, modification detection and copyright protection of the digital image was proposed. After the original image is transformed by the DWT(Discrete Wavelet Transform), the encrypted watermark information is embedded into the LSB(Least Significant Bit) of LL band on the low frequence domain for authenticating and detecting modified position in the image. And watermark information is embedded by exchanging the wavelet coefficient for the copyright protection. Thereby, we can authenticate the modification and detect the modified location by extracting the values of LSB on the low frequence domain. And we can perceive the copyright information of original image by extracting the embedded watermark on the high frequence domain.

• Journal of Korea Multimedia Society
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• v.5 no.5
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• pp.505-514
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• 2002

In this Paper, we propose a method of content-based image classification using neural network. The images for classification ate object images that can be divided into foreground and background. To deal with the object images efficiently, object region is extracted with a region segmentation technique in the preprocessing step. Features for the classification are texture and shape features extracted from wavelet transformed image. The neural network classifier is constructed with the extracted features and the back-propagation learning algorithm. Among the various texture features, the diagonal moment was more effective. A test with 300 training data and 300 test data composed of 10 images from each of 30 classes shows correct classification rates of 72.3% and 67%, respectively.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.7
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• pp.1437-1446
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• 2012

In this paper we propose a new stereo matching algorithm which is suitable for application to obtain depth information with high-speed in stereoscopic camera environment. For satisfying these condition we propose a new adaptive stereo matching technique using frequency information in discrete wavelet (DWT) domain and variable matching window. The size of the matching window is selected by analysis of the local property of the image in spatial domain and the feature and scaling factor of the matching window is selected by the frequency property in the frequency domain. For using frequency information we use local DWT and global DWT. We identified that the proposed technique has better peak noise to signal ratio (PSNR) than the fixed matching techniques with similar complexity.

• The Transactions of the Korea Information Processing Society
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• v.7 no.2S
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• pp.701-710
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• 2000

This paper presents a new method for an efficient coding of very low bit-rate color video based on adaptive wavelet transform. Our approach reveals that the coding process works more efficiently if the quantized wavelet coefficients are preprocessed by a mechanism exploiting the redundancies in the wavelet subband structure. Thus, we focuses optimized activity of coding part, and exhaustive overlapped block motion compensation is utilized to ensure coherency in motion compensated error frames, and raised cosine window is applied. The horizontal and vertical components of motion vectors are encoded separately using adaptive arithmetic coding while significant wavelet coefficients are encoded in bit-plane order using adaptive arithmetic coding. On average the proposed codec exceeds H.263 and ZTE in peak signal-to-noise ratio by as much as 2.07 and 1.38dB at 28 kbits, respectively. Fore entire sequence coding, 3DWCVC method is superior to H.263 and ZTE by 0.35 and 0.71dB on average, respectively.

• The Journal of the Korea Contents Association
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• v.6 no.1
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• pp.170-178
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• 2006

In this paper, the hybrid-watermarking method to make it possible to the authentication, modification detection and copyright protection of the digital image was proposed. After the original image is transformed by the DWT(Discrete Wavelet Transform), the encrypted watermark information is embedded into the LSB(Least Significant Bit) of LL band on the low frequence domain for authenticating and detecting modified position in the image. And watermark information is embedded by exchanging the wavelet coefficient for the copyright protection. Thereby, we can authenticate the modification and detect the modified location by extracting the values of LSB on the low frequence domain. And we can perceive the copyright information of original image by extracting the embedded watermark on the high frequence domain.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.1 s.106
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• pp.27-33
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• 2006

Fault diagnosis and condition monitoring for rotating machines are important for efficiency and accident prevention. The process of fault diagnosis is to extract the feature of signals and to classify each state. Conventionally, fault diagnosis has been developed by combining signal processing techniques for spectral analysis and pattern recognition, however these methods are not able to diagnose correctly for certain rotating machines and some faulty phenomena. In this paper, we add a minimum detection error algorithm to the previous method to reduce detection error rate. Vibration signals of the induction motor are measured and divided into subband signals. Each subband signal is processed to obtain the RMS, standard deviation and the statistic data for constructing the feature extraction vectors. We make a study of the fault diagnosis system that the feature extraction vectors are applied to K-means clustering algorithm and minimum detection error algorithm.