Abstract: In this paper，an image multi-watermark algorithm based on the combination of Logistic chaotic mapping and Turbo code is proposed.After that，difference information can be represented by binary images embedded in an image through the spread spectrum technology.By the excellent error-correcting of Turbo code and spread spectrum communication technology，the watermark is embedded in the DCT coefficients mid-frequency，which is encrypted by chaotic，coded by Turbo code and spread spectrum by difference Chaotic sequences，in accordance with the visual characteristics of the human eye.At the same time，the algorithm under several attack has been simulated in the paper.The experimental results show that the algorithm is good at invisibility and robust on implementating the watermark.

Key words: Turbo-codes, chaotic, spread spectrum, Discrete Cosine Transform（DCT） transform

摘要： 提出了一种基于logistic混沌映射和Turbo码相结合的多水印算法，利用扩频技术在一个图像上嵌入多个二值图像来代表不同信息。该算法利用Turbo码优异的纠错性能和扩频通信的多址技术，并根据人眼视觉特性，将经过混沌加密、Turbo码编码并使用不同的混沌序列扩频的水印嵌入到DCT变换系数的中频中。对算法在多种攻击下进行了仿真。实验结果表明，利用该算法实现的水印具有良好的不可见性和鲁棒性。

关键词: Turbo码, 混沌, 扩频, 离散余弦变换