通信專業(yè)文獻(xiàn)及翻譯--基于jpeg2000技術(shù)，融合dsp和fpga的可糾錯圖像傳輸系統(tǒng)

1、中 北 大 學(xué) 2008 屆 畢 業(yè) 設(shè) 計 說 明 書第 1 頁 共 15 頁英文原文 英文原文Mixed DSP /FPGA implementation of an error-resilient image transmission system based on JPEG2000Marco Grangetto,Enrico Magli, Maurizio Martina, Fabrizio VaccaAbstract This

2、 paper describes a demonstrator of an error-resilient image communication system over wireless packet networks, based on the novel JPEG2000 standard. In particular, the decoder implementation is addressed, which is the m

3、ost critical task in terms of complexity and power consumption, in view of use on a wireless portable terminal for cellular applications. The system implementation is based on a mixed DSP/FPGA architecture, which allows

4、to parallelize some computational tasks, thus leading to efficient system operation. 1 Introduction Nowadays, there is a growing interest in the end-to-end transmission of images, especially motivated by the short-term

5、deployment of next generation mobile communication services (UMTS-IMT2000). However, transmission in a networked, tetherless environment provides both opportunities and challenges. The wireless context implies that the d

6、ata may undergo bit errors and packet losses, making it necessary to foresee error recovery modalities. It is thereby necessary that image communication techniques are provided with the ability to recover, or at least co

7、nceal, the effect of such losses. The forthcoming JPEG2000 image com-pression standard has been designed to match these requirements, and embeds some error detection and concealment tools. This paper addresses the develo

8、pment of a demonstrator of an error-resilient JPEG2000 decoder implementation for image communication over a lossy packet network. The robustness to packet erasures is achieved by combining the flexibility of the JPEG200

9、0 framework with the powerfulness of source-channel adaptive, optimized Reed-Solomon codes. The decoder implementation is particularly significant in the context of wireless 中 北 大 學(xué) 2008 屆 畢 業(yè) 設(shè) 計 說 明 書第 3 頁 共 15 頁repres

10、entation of the included code-blocks, organized into packets. In order to form a progressive bitstream, i.e. one that can be only partially decoded with minimal penalty, the layers are formed and ordered in such a way th

11、at the most important information is placed at the beginning of the bitstream. The JPEG2000 decoder performs exactly the same steps (except for rate allocation), in reverse order: syntax parsing, codeblock decoding by EB

12、COT, inverse quantization, inverse DWT, and tile mosaicking; this is sketched in the right-hand-side box of Fig. 1. 2.2 Adaptive Reed-Solomon packet protection Although JPEG2000 embodies advanced error concealment techn

13、iques to mitigate the effect of errors, it does neither contain, nor specify any error correction method, in order to recover lost packets. On the other hand, packet losses are likely to occur in a network potentially su

14、bject to congestion, as is often the case in practice. In order to overcome this problem, a technique has been recently proposed, called Unequal Loss Protection (ULP), and based on the joint use of RS codes and packet in

15、terleaving, as shown in the left-hand-side of Fig. 1. Let us consider a maximum rate allocated to the image transmission, e.g. N packets of size L; the source bitstream is rowwise inserted in the interleaving matrix, fol

16、lowed by a proper amount of parity symbols, say Ti for the i-th row. The packets are read on the columns of the interleaver. The allocation problem consists in finding the optimal partitioning between source and code sym

17、bols for each row of the interleaver, so as to maximize the quality of service at the receiver; see for implementation details. At the decoder, due to the error correction capability of RS codes, the i-th row can be exac