• 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 Korea Academia-Industrial cooperation Society
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• v.4 no.3
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• pp.263-269
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• 2003

This paper focuses on lossy medical image compression methods for medical images that operate on three-dimensional(3D) irreversible integer wavelet transform. We offer an application of the Set Partitioning in Hierarchical Trees(SPIHT) algorithm〔l-3〕to medical images, using a 3-D wavelet decomposition and a 3-D spatial dependence tree. The wavelet decomposition is accomplished with integer wavelet filters implemented with the lifting method, where careful scaling and truncations keep the integer precision small and the transform unitary. As the compression rate increases, the boundaries between adjacent coding units become increasingly visible. Unlike video, the volume image is examined under static condition, and must not exhibit such boundary artifacts. In order to eliminate them, we utilize overlapping at axial boundaries between adjacent coding units. We have tested our encoder on medical images using different integer filters. Results show that our algorithm with certain filters performs as well. The improvement is visibly manifested as fewer ringing artifacts and noticeably better reconstruction of low contrast.

• Journal of Information Processing Systems
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• v.14 no.5
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• pp.1293-1300
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• 2018

For the disadvantages of multi-scale geometric analysis methods such as loss of definition and complex selection of rules in image fusion, an improved multi-focus image fusion method is proposed. First, the initial fused image is quickly obtained based on the lifting stationary wavelet transform, and a simple normalized cut is performed on the initial fused image to obtain different segmented regions. Then, the original image is subjected to NSCT transformation and the absolute value of the high frequency component coefficient in each segmented region is calculated. At last, the region with the largest absolute value is selected as the postfusion region, and the fused multi-focus image is obtained by traversing each segment region. Numerical experiments show that the proposed algorithm can not only simplify the selection of fusion rules, but also overcome loss of definition and has validity.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.8 s.179
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• pp.2100-2107
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• 2000

The wavelet theory is relatively a new development and now acquires popularity and much interest in many areas including mathematics and engineering. This work presents an adaptive wavelet method for a numerical solution of partial differential equations in a collocation sense. Due to the multi-resolution nature of wavelets, an adaptive strategy can be easily realized it is easy to add or delete the wavelet coefficients as resolution levels progress. Typical wavelet-collocation methods use interpolating wavelets having no vanishing moment, but we propose a new wavelet-collocation method on modified interpolating wavelets having 2 vanishing moments. The use of the modified interpolating wavelets obtained by the lifting scheme requires a smaller number of wavelet coefficients as well as a smaller condition number of system matrices. The latter property makes a preconditioned conjugate gradient solver more useful for efficient analysis.

• 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.

• Journal of Korea Multimedia Society
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• v.13 no.7
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• pp.943-949
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• 2010

This paper presents some improvements on VLSI implementation of lifting-based 9/7 wavelet transform by optimization hardware multiplication. The proposed solution requires less logic area and power consumption without performance loss compared to previous wavelet filter structure based on lifting scheme. This paper proposes a better approach to the hardware implementation using Lefevre algorithm based on extensions of Pattern search methods. To compare the proposed structure to the previous solutions on full multiplier blocks, we implemented them using Verilog HDL. For a hardware implementation of the two solutions, the logical synthesis on 0.18 um standard cells technology show that area, maximum delay and power consumption of the proposed architecture can be reduced up to 51%, 43% and 30%, respectively, compared to previous solutions for a 200 MHz target clock frequency. Our evaluation show that when design VLSI chip of lifting-based 9/7 wavelet filter, our solution is better suited for standard-cell application-specific integrated circuits than prior works on complete multiplier blocks.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1996.06a
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• pp.159-163
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• 1996

In this paper, a new image compression technique, which uses lifting scheme and pyramid vector quantization, is proposed. Lifting scheme is a new technique to generate wavelets and to perform wavelet transform, and pyramid vector quantization is a kind of vector quantization which dose not have codebook neither codebook generation algorithm. For the purpose of realizing more compression rate, an arithmetic entropy coder is used. Proposed algorithm is compared with other wavelet based image coder and with JPEG which uses DCT and adaptive Huffman entropy coder. Simulation results showed that the performance of proposed algorithm is much better than that of others in point of PSNR and bpp.

• Structural Engineering and Mechanics
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• v.35 no.2
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• pp.175-190
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• 2010

One of the intractable problems in multiresolution structural analysis is the decoupling computation between scales, which can be realized by the operator-orthogonal wavelets based on the lifting scheme. The multiresolution finite element space is described and the formulation of multiresolution finite element models for structural problems is discussed. Various operator-orthogonal wavelets are constructed by the lifting scheme according to the operators of multiresolution finite element models. A dynamic multiresolution algorithm using operator-orthogonal wavelets is proposed to solve structural problems. Numerical examples demonstrate that the lifting scheme is a flexible and efficient tool to construct operator-orthogonal wavelets for multiresolution structural analysis with high convergence rate.

• Proceedings of the IEEK Conference
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• 2003.07e
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• pp.1731-1734
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• 2003

In this paper, we describe an approach for image denoising using the lifting construction, with the spatial adaptive wavelet transform. The adaptive lifting scheme is implemented in spatial domain to be adjusted thresholds to reduce noise. In this approach we represent adaptive characteristics of biorthogonal wavelets for choosing predictors effectively. Predict filter is changed from sample to sample according to local signal features with their vanishing moments. We in this approach have implemented and applied to image denoising by finding a relevant minimax threshold. Experimental results show that the adaptive method of denoising process is compared with existing ones, such as non-adaptive wavelet, CRF(13, 7) and SWE(13, 7) wavelets used by JPEG2000.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.43 no.6 s.312
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• pp.76-82
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• 2006

In this paper, the biomedical signal compression method, which is combined with the multi-stage vector quantization and wavelet lifting scheme, is proposed. It utilizes the property of wavelet coefficients that give emphasis on approximation coefficients. The transmitted codebook index consists of the code vectors obtained by wavelet lifting coefficients of ECG and error signals from the 1024 block length, respectively. Each codebook is adaptively updated by the method comparing to the distance of input codevectors with candidate codevectors by using an pre-defined threshold value. The proposed compression method showed blow 3% in term of PRD and 276.62 bits/sec in term of CDR.