Abstract : in this paper , a variety of encryption methods for optical image security are comparatively studied . according to the different method , the encrypted image can be transformed into white or color noise . the encryption phase can be the random phase or the chaotic sequence as well as the calculated result by used of the phase retrieval algorithm . the image quality and the correlative recognition ability of decrypted image are affected by the different part of the decryption phase and the amount of high frequency or low frequency used in the process of decryption 文摘:本文分析比较了多种实现光学图象相位加密的方法，发现不同方法获得的加密图象有不同类型的噪音分布.无论加密相位是随机相位模板、浑沌序列的相位列阵，还是用相位重构迭代算法计算的结果，它们都能起到加密图象的功能.解密图象的质量或被相关识别的能力与解密过程中所使用正确解密相位的不同部分以及高低频分量多少有关，且其依赖程度是由不同的加密方法自身决定
In the introduction , we briefly introduce the history of symbolic dynamics development , the research of the symbolic dynamical system of an finite number of sym - bols , the research of the general symbolic dynamical system , the research of chaotic properties of shift and subshift of symbolic dynamical system and lists main conclusions in the paper 在引言部分，简要介绍了符号动力学发展的历史；有限个符号的符号动力系统与一般符号动力系统研究；符号动力系统移位及子移位的浑沌性质研究，并叙述了本文的主要结论。
If we take the idea of unity between subject and object by way of returning to chaos put forward by zhuangzi as the major tradition , then , the minor tradition might include such devices and purposes of poetic creation and criticism as tropes and emotional expressions , which are not thoroughly the above - mentioned oneness 在中国诗学中，如果把庄子所倡经由“齐物”向“浑沌”回归的主客一体的经验视为大传统，那么做诗和评诗的手段和目的即比兴和缘情，定位于物感或感兴，并非彻底的天人合一，因而都只能算是小传统。
