基于整型DCT变换的图象编码研究

为了既能保证图象无失真压缩，又能提高编码效率，给出了一种新的基于整型可逆DCT变换的嵌入式编码方法，并实现了基于DCT的无失真编码和有失真编码方案的完美结合，该算法是首先通过计算DCT浮点变换的整数可逆矩阵分解，从而得到可以整数实现的可逆矩阵变换，然后再利用得到的分解矩阵依次对图象样本进行变换；最后将变换得到的系数用多种高效编码方法进行编码，实验结果表明，该新方法用于无损压缩编码时，整型DCT明显好于浮点DCT，而且没有残差的编码问题；用于有损压缩编码时，两者的编码效果相近。

Image Coding Research Based on Integer DCT

In this paper the authors present a novel integer reversible DCT based embedded image coding scheme, which can integrate lossy and lossless coding schemes perfectly. Image coding is of great interest in applications where efficiency with respect to data storage or transmission bandwidth is sought. The discrete cosine transform(DCT) has been applied extensively to the area of image coding. It has nice decorrelation and excellent energy compaction properties and it can be easily implemented by hardware. In this paper the integer DCT transform is implemented by factoring the float DCT transform matrix into integer reversible transform series. Then the authors apply the series of matrices to image samples, and encode the coefficients by several effective coding algorithms. The simulation results illustrate that the integer DCT coding scheme is superior to the float DCT coding method in lossless coding, and the coding performance of integer DCT is close to that of float DCT in lossy coding.