第二代Bandelets变换定码率图像压缩

Fixed bitrate image compression based on second generation Bandelets transform

由于第二代Bandelets变换是由量化步长来控制最佳Bandelet化过程,难以实现定码率图像压缩。为了解决这个问题,提出了一种通过非线性逼近来控制最佳Bandelet化过程的方法。同时采用了沿几何流的方向小波变换方法,直接把JPEG2000的编解码器应用到Bandelets变换系数上进行有效的图像压缩,而无需重新构造上下文模型。实验表明,提出的压缩方法具有很好的边缘和纹理保护能力,特别对于直线纹理图像,压缩性能优于JPEG2000标准。

Image compression based on the second generation Bandelets transform,whose optimized bandeletization is controlled by quantization step,cannot realize fixed bitrate image compression.To overcome this problem,the paper presents a non-linear approximation method to control the optimized bandeletization.Then,the oriented wavelet transform along geometric flow is adopted. The JPEG2000 eodec is directly employed on bandelets coefficients to implement effective image compression without changing context model.Experiments show that the proposed compression method exceeds JPEG2000 standard in compression performance and ability of image edges and texture preservation.