79 research outputs found
High speed VLSI architectures for DWT in biometric image compression: A study
AbstractBiometrics is a field that navigates through a vast database and extracts only the qualifying data to accelerate the processes of biometric authentication/recognition. Image compression is a vital part of the process. Various Very Large Scale Integration (VLSI) architectures have emerged to satisfy the real time requirements of the online processing of the applications. This paper studies various techniques that help in realizing the fast operation of the transform stage of the image compression processes. Various parameters that may involve in optimizations for high speed like computing time, silicon area, memory size etc are considered in the survey
Two Dimensional Dual-Mode Lifting Based Discrete Wavelet Transform
Hardware Simplicity, Multiplier-less architecture is proposed which is applicable for both lossy and lossless coding
New memory-efficient hardware architecture of 2-D dual-mode lifting-based discrete wavelet transform for JPEG2000
[[abstract]]This work presents new algorithms and hardware architectures to improve the critical issues of the 2-D dual-mode (supporting 5/3 lossless and 9/7 lossy coding) lifting-based discrete wavelet transform (LDWT). The proposed 2-D dual-mode LDWT architecture has the advantages of low-transpose memory, low latency, and regular signal flow, which is suitable for VLSI implementation. The transpose memory requirement of the N ?? N 2-D 5/3 mode LDWT is 2N, and that of 2-D 9/7 mode LDWT is 4N. According to the comparison results, the proposed hardware architecture surpasses previous architectures in the aspects of lifting-based low-transpose memory size. It can be applied to real-time visual operations such as JPEG2000, MPEG-4 still texture object decoding, and wavelet-based scalable video coding.[[notice]]需補會議日期、性質、主辦單位[[conferencedate]]20081119~2008112
Modified Lifting Scheme for DWT along with Parallel scanning Architecture 1
Abstract To overcome the inefficiencies in the JPEG standard and serve emerging areas of mobile and Internet communications, the new Lifting Scheme and processing element has been developed based on the principles of DWT. Previous DWT architectures are mostly based on the lift ing scheme/flipping structure where at least four pipelining stages were required for each multiplier or a large temporal buffer is needed. In this brief, modifications are made to the lifting scheme, and the intermediate results are recombined in the processing element and stored to get three number of pipelining stages and with reduced design complexity, computational time and to get the result in 2Dimensional image. Through optimizing the lifting scheme, Wu and Lin [10] implemented the parallel 2-D DWT. The design is a pipelined two-input/two-output architecture, and a 2×2 transposing module with four registers was developed. In addition, the critical path delay is one Tm. Nevertheless, it needs eight pipelining stages to complete the 1-D DWT and makes the total number of registers reach 22. The flipping structure is another important DWT architecture that was proposed by Huang et al. In this brief, further optimization on the processing element is proposed to overcome shortages in previous works and minimize sizes of the logic units and the memory without loss of the throughput. By recombining the intermediate results of the row and column transforms, the number of pipelining stages and registers is reduced, while keeping the critical path delay as Tm. In addition, a novel architecture is developed to implement the 2-D DWT based on the above modified scheme. The parallel scanning method is employed to reduce the computational time. As a result, our design achieves higher efficiency. The rest of this brief is organized as follows. Section II reviews the lifting scheme of the DWT in and Section III presents the proposed architecture for the 2-D DWT, and Section IV provides implementation results and comparisons with previous architectures. Conclusion is drawn in Section
Development of Lifting-based VLSI Architectures for Two-Dimensional Discrete Wavelet Transform
Two-dimensional discrete wavelet transform (2-D DWT) has evolved as an essential
part of a modem compression system. It offers superior compression with good image
quality and overcomes disadvantage of the discrete cosine transform, which suffers
from blocks artifacts that reduces the quality of the inage. The amount of
computations involve in 2-D DWT is enormous and cannot be processed by generalpurpose
processors when real-time processing is required. Th·"efore, high speed and
low power VLSI architecture that computes 2-D DWT effectively is needed. In this
research, several VLSI architectures have been developed that meets real-time
requirements for 2-D DWT applications. This research iaitially started off by
implementing a software simulation program that decorrelates the original image and
reconstructs the original image from the decorrelated image. Then, based on the
information gained from implementing the simulation program, a new approach for
designing lifting-based VLSI architectures for 2-D forward DWT is introduced. As a
result, two high performance VLSI architectures that perform 2-D DWT for 5/3 and
9/7 filters are developed based on overlapped and nonoverlapped scan methods. Then,
the intermediate architecture is developed, which aim a·: reducing the power
consumption of the overlapped areas without using the expensive line buffer. In order
to best meet real-time applications of 2-D DWT with demanding requirements in
terms of speed and throughput parallelism is explored. The single pipelined
intermediate and overlapped architectures are extended to 2-, 3-, and 4-parallel
architectures to achieve speed factors of 2, 3, and 4, respectively. To further
demonstrate the effectiveness of the approach single and para.llel VLSI architectures
for 2-D inverse discrete wavelet transform (2-D IDWT) are developed. Furthermore,
2-D DWT memory architectures, which have been overlooked in the literature, are
also developed. Finally, to show the architectural models developed for 2-D DWT are
simple to control, the control algorithms for 4-parallel architecture based on the first
scan method is developed. To validate architectures develcped in this work five
architectures are implemented and simulated on Altera FPGA.
In compliance with the terms of the Copyright Act 1987 and the IP Policy of the
university, the copyright of this thesis has been reassigned by the author to the legal
entity of the university,
Institute of Technology PETRONAS Sdn bhd.
Due acknowledgement shall always be made of the use of any material contained
in, or derived from, this thesis
Discrete wavelet transform realisation using run-time reconfiguration of field programmable gate array (FPGA)s
Abstract: Designing a universal embedded hardware architecture for discrete wavelet transform is a challenging problem because of the diversity among wavelet kernel filters. In this work, the authors present three different hardware architectures for implementing multiple wavelet kernels. The first scheme utilises fixed, parallel hardware for all the required wavelet kernels, whereas the second scheme employs a processing element (PE)-based datapath that can be configured for multiple wavelet filters during run-time. The third scheme makes use of partial run-time configuration of FPGA units for dynamically programming any desired wavelet filter. As a case study, the authors present FPGA synthesis results for simultaneous implementation of six different wavelets for the proposed methods. Performance analysis and comparison of area, timing and power results are presented for the Virtex-II Pro FPGA implementations
DESIGN AND IMPLEMENTATION OF LIFTING BASED DAUBECHIES WAVELET TRANSFORMS USING ALGEBRAIC INTEGERS
Over the past few decades, the demand for digital information has increased drastically. This enormous demand poses serious difficulties on the storage and transmission bandwidth of the current technologies. One possible solution to overcome this approach is to compress the amount of information by discarding all the redundancies. In multimedia technology, various lossy compression techniques are used to compress the raw image data to facilitate storage and to fit the transmission bandwidth.
In this thesis, we propose a new approach using algebraic integers to reduce the complexity of the Daubechies-4 (D4) and Daubechies-6 (D6) Lifting based Discrete Wavelet Transforms. The resulting architecture is completely integer based, which is free from the round-off error that is caused in floating point calculations. The filter coefficients of the two transforms of Daubechies family are individually converted to integers by multiplying it with value of 2x, where, x is a random value selected at a point where the quantity of losses is negligible. The wavelet coefficients are then quantized using the proposed iterative individual-subband coding algorithm. The proposed coding algorithm is adopted from the well-known Embedded Zerotree Wavelet (EZW) coding. The results obtained from simulation shows that the proposed coding algorithm proves to be much faster than its predecessor, and at the same time, produces good Peak Signal to Noise Ratio (PSNR) at very low bit rates.
Finally, the two proposed transform architectures are implemented on Virtex-E Field Programmable Gate Array (FPGA) to test the hardware cost (in terms of multipliers, adders and registers) and throughput rate. From the synthesis results, we see that the proposed algorithm has low hardware cost and a high throughput rate
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