通过对DEM数据进行分块傅里叶变换和频谱分析，结合人类视觉系统和DEM数据特征，自适应地确定水印嵌入位置，将水印信息以加性法则嵌入到傅里叶低频系数的幅值上，然后对DEM数据进行分块傅里叶逆变换，得到含水印信息的DEM数据。实验结果表明，该算法不仅具有很好的透明性，而且对DEM数据的精度影响较小，能够满足一定的应用要求，具有良好的抗噪能力。

This paper introduces an adaptive watermarking algorithm for DEM. This proposed method can utilize human visual system(HVS), features of DEM data and discrete Fourier transform(DFT) to determine adaptively the location where the watermark can be hidden. And then, the watermark information is added to the lowness frequency of the texture region DFT. Experimental results show that the novel watermarking scheme for DEM has good imperceptibility, little effect on DEM accuracy and is robust to noise attack.