摘要
文中定义了图像块的数字压缩技术(DCT)频域内积,并证明了该内积等于时域内积,从而可根据频域内积大小来作为分形编码中最佳匹配块的判断,并推导出DCT域上恒等变换与其余7种对称变换的关系。本文将值域块分为平稳、中间和活跃三类,研究对于不同类型的值域块,求频域内积时,保留低频系数个数和解码图像质量之间的关系,并提出了基于DCT域内积和方差的分形图像编码算法。在实验中,将本文算法分别同文献[2]、[3]中方法进行了比较,结果表明,本文算法能在基本保证解码图像质量的同时,大大提高编码速度。
The inner product of digital compressing technique(DCT) coefficients is defined which is equal to the inner product of spatial coefficients.It can be judged as close matches.The relationship is induced between indentity transformation and the rest transformations on DCT domain.The range block is separated into three classes∶steady,middle and active.The relationship between the nubmer of low frequency coefficients and the quality of decoded image is analyzed.The algorthm of fractal image encoding is proposed based on the inner product of DCT coefficients and local variance.The algorithm is compared with that in literature[2] and [3].Experiments show that the speed can be improved greatly with the ensurance of the decoded image quality.
出处
《激光与红外》
CAS
CSCD
北大核心
2005年第4期303-306,共4页
Laser & Infrared
关键词
分形编码
DCT
内积
fractal coding
DCT
inner product
