视频中的扩频嵌入是一种典型的隐写方法，能够抵抗视频压缩、噪声添加等多种攻击。为了有效检测利用该方法嵌入的隐藏信息，将隐写过程建模为加性高斯噪声的叠加过程，分析了噪声叠加对视频序列的时间相关性和空间相关性的影响，提出了基于时空相关性的隐写分析算法。该算法利用视频序列中各帧的四方向差分直方图度量隐写对空间相关性的影响，同时利用相邻帧帧间差分的直方图度量隐写对时间相关性的影响。与现有算法相比，本文算法实现简单，实验结果表明本文算法具有更好的检测性能。

Spread-spectrum embedding for video, which can resist many attacks such as video compression and noise addition, is a representative steganography method. In order to effectively detect the hidden information embedded by the method, the steganography procedure is modeled as the addition of additive Gaussian noise. By analyzing the influence on temporal correlation and spatial correlation of video owing to noise addition, a steganalysis algorithm based on spatial-temporal correlation is proposed. The algorithm uses a difference image histogram of four directions to measure the influence of spatial correlation, and temporal correlation is measured by the histogram of frame difference. Experimental results show the algorithm is easier to implement and better in detection performance than other methods.