臺灣博碩士論文加值系統

JPWL 是由以JPEG2000為基礎所延伸過來的新圖檔格式，除了在容易發生錯誤的網路仍具有高效率傳輸外，特別的是JPWL提供了許多工具與方法針對資料的防錯保護與更正，例如: 前饋式錯誤更正編碼(Forward Error Correcting codes)，不等量錯誤保護 (Unequal Error Protection)及資料分割(partition)與交錯排列(interleaving)。
在本篇文章中，我們以JPWL為基礎提出新的保護方式讓標準的JPEG2000檔案格式適用於容易發生錯誤的網路。想要廣泛地將彩色圖應用在無線通訊上，JPEG2000 必須強化傳輸錯誤恢復能力。首先，我們用錯誤保護區段(Error Protection Block)來保護最敏感的主要檔頭(main header)及塊狀檔頭(tile header)，其次，在資料串(codestream)中插入不等量錯誤保護，這個方式可以讓比較重要的資料得到較多的保護，然後，以交錯(interleaving)及解開交錯(de-interleaving)資料排列處理來強化錯誤恢復能力，最後，加入一些特殊的記號段(marker segment)以減少錯誤的繼續傳播。
而實際上，任何的錯誤更正碼對網路而言也是一種冗餘資訊，我們的主要目標是讓網路維持在有效率的狀況下並保證最重要的部分資料能安全傳輸，在一般的無線通訊系統約有10-3 的位元錯誤率(bit error rate)，在本篇文章中所提到的方法可傳送JPEG2000彩色圖案讓品質保持在PSNR=30 dB以上且網路中的損耗少於5dB, 這是當冗餘資訊量等於7%時的條件。

JPWL (JPEG2000 part 11) is an extension of the JPEG2000 baseline specification in order to enable the efficient transmission of JPEG2000 codestream over an error-prone network. In particular, JPWL supports a set of tools and methods for error protection and correction such as Forward Error Correcting (FEC) codes, Unequal Error Protection (UEP), and data partitioning and interleaving.
In this thesis, based on JPWL specification, we propose a new error protection scheme for JPEG2000 standard image over an error prone network. To be widely adopted for wireless color image applications, JPEG2000 has to improve error-resilience. Therefore, we develop a tool by adopted follow approaches. First, EPB (Error Protection Block) marker segment is used to protect most sensitivity of main header and tile header. Second, the Unequal Error Protection (UEP) is inserted to protect whole codestream. In UEP algorithm, more channel protecting codes are assigned to more sensitive parts of the codestream. Third, the interleaving and de-interleaving process is used for improved error resilience. Last, some extra marker segments are added to reduce the error propagation.
Actually, any error correction codes are also redundancy codes for network. Our major goal is to keep the network as an efficient transmission system and guarantee the most important data are transmitting safely. In a wireless transmission system, the typical Bit Error Rate (BER) is 10-3, the proposed scheme in this thesis can transmit the JPEG2000 color image and maintain the quality of image with at least PSNR=30 dB and less than 5 dB loss in the network as the redundancy is 7%.

ABSTRACT (in Chinese)...I
ABSTRACT (in English)...II
ACKNOWLEGMENT...III
CONTENTS...IV
LIST OF FIGURES...VI
LIST OF TABLES...VIII
CHAPTER 1 INTRODUCTION...1
1.1 Motivation...1
1.2 Objective...1
1.3 Approaches...2
1.4 Organization of this thesis...4
CHAPTER 2 BRIEF INTRODUCTION TO JPWL...4
2.1 JPEG2000 Overview...5
2.2 JPWL Overview...5
2.3 JPWL Marker Segments...10
2.3.1 Error Protection Block (EPC)...13
2.3.2 Error Protection Block (EPB)...14
2.3.3 Error Sensitivity Descriptor (ESD)...15
2.3.4 Residual Errors Descriptor (RED)...15
2.4 JPWL Coding Procedure and RA Registration Process...16
2.4.1 Encoding Procedure...17
2.4.2 Decoding Procedure...19
2.4.3 JPWL RA Registration Process...21
CHAPTER 3 THE PROPOSED IMAGE CODEC...23
3.1 Forward Error Correction...23
3.2 Unequal Error Protection...25
3.3 Error Sensitivity Computation...28
3.3.1 Relative contribution of each packet...29
3.3.2 Relative penalty of each packet...32
3.3.3 Use UEP to protect the most sensitivity of packet...36
3.4 Redundancy FEC Trade Off Error Correction...36
3.5 Error Concealment with Weighted Interpolation...38
3.5.1 Interleaving against burst noise...38
3.5.2 Weighted interpolation...39
CHAPTER 4 SIMULATION RESULTS...41
4.1 Flow Chart of Source- channel Coding Algorithm...41
4.2 Simulation Tools...42
4.3 Experiment Results...44
4.3.1 Bit Error Rate vs. JPWL error protection...44
4.3.2 Redundancy FEC vs. JPWL error protection...46
4.3.3 Reconstructed sample image by simulation tools...47
CHAPTER 5 CONCLUSIONS...52
REFERENCES...53

[1] A. Leon-Garcia and I. Widjaja, Communication Networks, McGraw-Hill Higher Education, p. 153, 2000.
[2] ISO/IEC JTC1/SC29/WG1 (ITU-T SG16), “JPEG 2000 image coding system – Part 11: Wireless JPEG 2000 – Final Committee Draft,” Mar. 2005.
[3] ISO/IEC JTC1/SC29/WG1 (ITU-T SG8), “JPEG 2000 Part I Final Committee Draft Version 1.0,” Apr. 2000.
[4] H. Zhang and J. Fritts, “EBCOT coprocessing architecture for JPEG2000,” Dept. of Computer Science and Engineering, Washington University, 2004.
[5] F. Dufaux and D. Nicholson, “JPWL: JPEG 2000 for Wireless Applications,” 2004.
[6] http://www.jpeg.org
[7]http://en.wikipedia.org/wiki/Forward_error_correction
[8]http://www.altera.com/products/ip/dsp/error_detection_correction/ipm-index.jsp
[9] http://www.4i2i.com/reed_solomon_codes.htm
[10] H. Lee, Master Thesis, “Robust Color Image Transmission Over Noisy Channels,” Institute of Communication Engineering, Tatung University, p. 15, July 2004.
[11] M. Marka and J. E. Fowler, “Object-Based Unequal Error Protection,” Engineering Research Center, Mississippi State University, Feb. 2002.
[12] http://www.openjpeg.org/