【作者】 王战盟；

【导师】 谷爱昱；

【作者基本信息】 广东工业大学 ， 系统工程， 2007， 硕士

【摘要】 JPEG标准是当前在静态图像编解码领域中应用最为广泛的一种图像编解码技术，被广泛应用于图像的存储和传输。随着嵌入式技术的发展，JPEG图像编解码技术被用到了许多嵌入式系统中，产生了如数码相机、多媒体手机、掌上电脑等许多嵌入式产品。目前JPEG编解码多采用专用集成电路ASIC来实现，这种方法集成度较高，实现起来相对容易，但成本较高，升级拓展困难。一种更加灵活的方案是基于高性能的处理器，如ARM、DSP等，通过采用各种优化算法实现JPEG编解码功能，该方案使系统功能拓展和升级可以通过软件升级来实现，具有高度的灵活性和适应性，而且通过软件来实现系统功能的扩展和升级成本也较硬件升级低。本文的研究题目：“基于ARM的嵌入式静态图像显示系统的研究与实现”，研究了在ARM硬件平台上采用软件编程的方法来实现JPEG图像解码和显示。本文首先介绍了JPEG静态图像编码解标准的基本原理，然后基于SAMSUNG公司的ARM处理器S3C4480X设计出用于静态图像解码和显示的硬件平台，并根据该硬件平台设计了相关的引导程序、驱动程序和显示模块的显示程序，为最终实现一个嵌入式的图像处理系统做好了软硬件基础。接着进一步分析和研究了JPEG基本系统的解码过程，JPEG解码过程主要由头文件信息处理、熵解码、反量化、反离散余弦变换和色度空间转换五个部分组成。在对解码过程中运算量最大，耗时最多的反离散余弦变换IDCT部分，结合S3C4480X的特点和反离散余弦变换原理，将二维8×8矩阵的反离散余弦变换运算转换成16次的一维8点反离散余弦变换运算，并对一维8点的反离散余弦变换采用一种快速算法，高效快速地实现了反离散余弦变换。最后实现了基于ARM平台的JPEG静态图像的解码显示系统，并且从S3C4480X的硬件特性和C程序结构方面对解码程序做了的优化。通过从解码的图像质量和速度两个方面进行测试，系统能够达到图像重构的要求和实时解码显示的目标。更多还原

【Abstract】 JPEG is a kind of image encoding and decoding technique used mostwidely in the still image field to save and transmit the image informationnowadays. With the development of embedded technique, JPEG imageencoding and decoding technique has been used in many embedded systems,accordingly many embedded products appear, such as multimedia digitalcamera, and palmtop computer etc. At present the special integrated circuitASIC is often adopted to implement JPEG image encoding and decoding.The integrated level of this method is high and easy to realize, but its cost ishigh and it is difficult to upgrade and develop. Another more flexiblescheme is based on a high-performance processor such as ARM, DSP and soon, and all kinds of optimization algorithm are used to implement JPEGimage encoding and decoding. The method makes the system upgrading andfunction expanding realized through the software, which has lower cost thanhardware upgrade and has high flexibility and adaptability. The researchtopic of this article is "The Research and Realization of Still Image DisplaySystem Based on ARM" in which based on ARM hardware platform, thesoftware program is adopted to implement JPEG image decoding anddisplay.JPEG standard is introduced firstly in the paper then based on ARMprocessor S3C44BOX which come from SAMSUNG, a hardware processingplatform used to finish still image decoding and display has been designed.According to the hardware platform, bottom driver program and displaymodule program have been designed, which provide the software andhardware foundation for realizing the embedded image processing systemfinally. Further analyses and investigations have been done on the decoding process of JPEG Baseline system. The process of JPEG image decoding ismade up of five parts: tag code information processing, entropy decoding,dequantization, inversed discrete cosine transform and color spaceconverter. Because of inversed discrete cosine transform costing the mostquantity of time in the process of decoding, we adopt at row and columnmethod and convert 8×8 two-dimensional inversed discrete cosine transforminto 8 point one-dimensional inversed discrete cosine transform, whichrealizes inversed discrete cosine transform algorithm with high efficiencyand speed. Finally JPEG still image decoding and display processing systemhas been realized based on this hardware platform. In the end the fartheroptimization has been done to the decoding program from the aspects ofhardware characteristic of S3C44B0X and C program structure. Through thetest of decoding result to image quality and speed, the system can reach therequirement of image reconfiguration and the target of real-time decodingand display.更多还原