研究了频率域上的分形图象编码，与空间域上的分形图象编码相比，它有两个突出的特点：分阶的亮度变换和几何变换的简化与合并。本文的理论分析和实验数据都表明，无论是在编码时间和压缩比方面，还是在解码的收敛性和图象保真度方面，频率域上的分形图象编码都要优于相应的空间域上的分形图象编码。

This paper presents a new scheme of fractal coding in the frequency domain. Compared with fractal coding in the spatial domain,the proposed scheme has two features: segmented luminance transform, simplification and combination of geometrical transform. Theory analysis and experiment show that this scheme is superior in encoding time and decoder contractility. Meanwhile, it shares alittle higher compression ratio and higher image fidelity.