基于DCT的图像压缩编码算法毕业论文.doc

基于DCT的图像压缩编码算法及其MATLAB实现 摘 要 在信息爆炸的当今社会，图像压缩技术是促进多媒体技术进一步发展的关键技术之一。对于图像来说, 如果需要进行快速或实时传输, 就要对图像进行压缩。离散余弦变换(DCT)由于在图像压缩编码方面的独有优势，被广泛推广和应用。 本文首先说明了图像压缩在现代通信中的必要性和可行性以及MATLAB图像处理工具箱的相关知识，然后重点介绍了JPEG压缩编码的具体过程和方法，详细介绍了编码中DCT变换、量化、熵编码和霍夫曼编码等模块的原理。并对JPEG和JPEG2000进行了比较。最后分析了图像经过不同压缩比时，图像质量的变化情况。 实验结果表明基于DCT变换的图像压缩方法简单，方便，即能保证有较高的压缩比，又能保证较好的图像质量，应用MATLAB仿真出来的结果比较好的反应了其编码原理。 关键词：图像压缩技术， DCT变换，JPEG图像， MATLAB图像处理工具箱 IMAGE COMPRESSION CODING TECHNOLOGY ALGORITHM BASED ON DCT AND REALIZATION BASED ON MATLAB Abstract In the age of information explosion nowadays，image compression is one of the key technologies to promote the further development of multimedia technology．For images,if necessary for fast or real- time transmission,it has to compress the image.Due to the unique advantage of discrete cosine transform(DCT)in image compression and coding，it is widely extended and applied． The outset that the image compression in the modern communications and the necessity and feasibility of MATLAB image processing toolbox of knowledge, and then focuses on the specific process of JPEG compression and methods described in detail in the DCT transform coding, quantization, entropy coding and the principle of Huffman coding and other modules. Performance between JPEG2000 and JPEG are compared .Finally after a different compression ratio of the image, the image quality changes. Experimental results show that the results table DCT-based image compression method is simple and convenient, not only guarantee a higher compression ratio, but also to ensure both better image quality, MATLAB simulation results reflect a better algorithm principle. KEY WORDS: image compression technology,DCT transform,JPEG image,MATLAB Image Processing Toolbox 目录 第一章 绪论 1 1.1 数字图像压缩编码的可能性 1 1.2 图像压缩技术 1 1.2.1 图像编码技术的发展和现状 1 1.2.2 离散余弦变换（DCT） 2 1.3 MATLAB 及其图像处理工具箱 3 第二章 常见的图像压缩方法 4 2.1 RLE(Run Length Encoding)压缩算法 4 2.2 LZW编码 5 2.3哈夫曼(Huffman)编码 5 2.4基于小波的图像压缩技术 6 2.5变换编码 6 2.6基于分形的图像压缩与编码 7 第三章 基于DCT的图像压缩编码算法 8 3.1