• Korean Journal of Remote Sensing
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• v.25 no.3
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• pp.215-223
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• 2009

The noise removal as a preprocessing was tried with various kinds of wavelet pairs. Wavelet transform for 2D images generally uses the same wavelets as basis functions in horizontal and vertical directions. A method with different wavelets was tried for each direction separately, which gives more precise interpretation of the classification. Total 486 pairs of wavelets from nine basis functions were tried to remove image noises. The classification accuracies before and after the noise removal were compared. Although all kinds of wavelet pairs showed the increased accuracies in classification, there were best and worst wavelet pairs depending on the data sets. Wavelet pairs with low energy percentage of LL band showed the high classification accuracy. A pattern was found in the results that very similar vertical accuracy was distributed for each horizontal ones. Since Haar is the shortest length filter, Haar could be a predictor wavelet to find the good wavelet pairs.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.14 no.4
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• pp.249-255
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• 2014

We present a simple method to watermark three-dimensional (3D) triangular meshes that have been generated from the depth data of the Kinect sensor. In contrast to previous methods, which maintain the shape of 3D triangular meshes and decide the embedding place, requiring calculations of vertices and their neighbors, our method is based on selecting one of the coordinate axes. To maintain shape, we use discrete wavelet transform and constant regularization. We know that the watermarking system needs the information to be embedded; we used a text to provide that information. We used geometry attacks such as rotation, scales, and translation, to test the performance of this watermarking system. Performance parameters in this paper include the vertices error rate (VER) and bit error rate (BER). The results from the VER and BER indicate that using a correction term before the extraction process makes our system robust to geometry attacks.

• Journal of Electrical Engineering and Technology
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• v.8 no.5
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• pp.1188-1193
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• 2013

In content based image retrieval (CBIR) system, the images are represented based upon its feature such as color, texture, shape, and spatial relationship etc. In this paper, we propose a MRI Image Retrieval using wavelet transform with mahalanobis distance measurement. Wavelet transformation can also be easily extended to 2-D (image) or 3-D (volume) data by successively applying 1-D transformation on different dimensions. The proposed algorithm has tested using wavelet transform and performance analysis have done with HH and $H^*$ elimination methods. The retrieval image is the relevance between a query image and any database image, the relevance similarity is ranked according to the closest similar measures computed by the mahalanobis distance measurement. An adaptive similarity synthesis approach based on a linear combination of individual feature level similarities are analyzed and presented in this paper. The feature weights are calculated by considering both the precision and recall rate of the top retrieved relevant images as predicted by our enhanced technique. Hence, to produce effective results the weights are dynamically updated for robust searching process. The experimental results show that the proposed algorithm is easily identifies target object and reduces the influence of background in the image and thus improves the performance of MRI image retrieval.

• Korean Journal of Remote Sensing
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• v.24 no.1
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• pp.57-64
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• 2008

In the previous study, the Haar wavelet was used as the sole basis function for the 3D discrete wavelet transform because the number of bands is too small to decompose a remotely sensed image in band direction with other basis functions. However, it is possible to use other basis functions for wavelet decomposition in horizontal and vertical directions because wavelet decomposition is independently performed in each direction. This study aims to classify a high spatial resolution image with the six types of basis function including the Haar function and to compare those results. The other wavelets are more helpful to classify high resolution imagery than the Haar wavelet. In overall accuracy, the Coif4 wavelet has the best result. The improvement of classification accuracy is different depending on the type of class and the type of wavelet. Using the basis functions with long length could be effective for improving accuracy in classification, especially for the classes of small area. This study is expected to be used as fundamental information for selecting optimal basis function according to the data properties in the 3D DWT based image classification.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.4B
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• pp.763-770
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• 2000

In this paper, a new stereo image compression algorithm is suggested in which the residual image extracted from the stereo image by the disparity-compensated prediction method is compressed using the wavelet transform considering the inter & intra correlation between subbands. The compression performance of the proposed method is significantly improved by comparing with the conventional algorithm such as EPIC, EPWIC & JPEG through the computer simulation and the PSNR is also increased about 3.5dB compared with the EPIC. Finally, the stereo image having a good 3D effect can be reconstructed from the compressed image data by the proposed method.

• Journal of the Semiconductor & Display Technology
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• v.5 no.2 s.15
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• pp.19-25
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• 2006

This paper focuses on lossy medical image compression methods for medical images that operate on three-dimensional(3-D) irreversible integer wavelet transform. We offer an application of unbalanced tree structure algorithm to medical images, using a 3-D unbalanced wavelet decomposition and a 3-D unbalanced spatial dependence tree. The wavelet decomposition is accomplished with integer wavelet filters implemented with the lifting method. We have tested our encoder on volumetric medical images using different integer filters and coding unit sizes. The coding unit sizes of 16 slices save considerable dynamic memory(RAM) and coding delay from full sequence coding units used in previous works. If we allow the formation of trees of different lengths, then we can accomodate more transaxial scales than three. The encoder and decoder can then keep track of the length of the tree in which each pixel resides through the sequence of decompositions. Results show that, even with these small coding units, our algorithm with certain filters performs as well and better in lossy coding than previous coding systems using 3-D integer unbalanced wavelet transforms on volumetric medical images.

• Journal of Korea Multimedia Society
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• v.10 no.6
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• pp.737-744
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• 2007

This paper proposes the blind watermarking algorithm for digital video based on magnitude modulus subband in wavelet transform domain. After transforming each of frames into wavelet domain, the proposed algorithm divides LH, HL, and HH subbands of 2-level into $3{\times}3$ blocks and calculates average magnitude modulus of all blocks. Then the watermark bit is embedded into a target magnitude modulus comparing with an average magnitude modulus within a block. Experimental results were confirmed that the proposed algorithm has the good robustness against MPEG and frame attacks than the conventional algorithm.

• Journal of Broadcast Engineering
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• v.11 no.2 s.31
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• pp.164-173
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• 2006

The data structure of the concentric mosaic can be regarded as a video sequence with a slowly panning camera. We take a concentric mosaic with match or alignment of video sequences. Also the concentric mosaic required for huge memory. Thus, compressing is essential in order to use the concentric mosaic. Therefore we need the algorithm that compressed data structure was maintained and the scene was decoded. In this paper, we used 3D lifting transform to compress concentric mosaic. Lifting transform has a merit of wavelet transform and reduces computation quantities and memory. Because each frame has high correlation, the complexity which a scene is detected form 3D transformed bitstream is increased. Thus, in order to have higher performance and decrease the complexity of detecting of a scene we executed 3D lifting and then transformed data set was sequently compressed with each frame unit. Each frame has a flexible bit rate. Also, we proposed the algorithm that compressed data structure was maintained and the scene was decoded by using property of lifting structure.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.12
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• pp.2313-2327
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• 1994

As the communication environment evolves, there is an increasing need for multiresolution image coding. To meet this need, the entrophy constratined vector quantizer(ECVQ) for coding of image pyramids by spline wavelet transform is introduced in this paper. This paper proposes a new scheme for image compression taking into account psychovisual feature both in the space and frequency domains : this proposed method involves two steps. First we use spline wavelet transform in order to obtain a set of biorthogonal subclasses of images ; the original image is decomposed at different scale using a pyramidal algorithm architecture. The decomposition is along the vertical and horizontal directions and maintains constant the number of pixels required the image. Second, according to Shannon's rate distortion theory, the wavelet coefficients are vectored quantized using a multi-resolution ECVQ(entropy-constrained vector quantizer) codebook. The simulation results showed that the proposed method could achieve higher quality LENA image improved by about 2.0 dB than that of the ECVQ using other wavelet at 0.5 bpp and, by about 0.5 dB at 1.0 bpp, and reduce the block effect and the edge degradation.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.50 no.3
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• pp.120-129
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• 2001

A two-degree-of-freedom quarter-car model is used as the basis for LQ and the proposed controller design for a semi-active suspension. The LQ controller results in the best rms performance trade-offs(as defined by performance index) between ride, handling and packaging requirements. In LQ controller, however, the conflict between road holding and ride comfort remains. The adaptive semi-active suspension control based on the road frequency are introduced in this paper. With this method, the trade-off between road holding and ride comfort can be relaxed. The road frequency is estimated by wavelet transform if rattle space signal. The simulation results show that the proposed controller is superior to the conventional LQ controller.