精度可控的倾斜摄影三维模型可逆水印算法

Precision-Controlled Reversible Watermarking Algorithm for 3D Model of Oblique Photography

现有倾斜摄影三维模型可逆水印算法大部分只能恢复单一精度数据,难以满足不同用户需求。该文提出一种恢复数据精度可控的倾斜摄影三维模型可逆水印算法。首先,利用顶点法向量夹角均值具有全局稳定性的特点,对三维模型特征点与非特征点进行划分;其次,以每个特征点为中心,以其与非特征点距离的比值为索引进行分组;最后,将每组中的唯一特征点作为原点,构建球面坐标系,以坐标系的半径作为水印信息的载体,在不同位置嵌入水印信息。实验表明,该算法在提取水印时,可实现恢复数据的精度可控,且对倾斜摄影三维模型常规攻击具有良好的鲁棒性。

The existing reversible watermarking algorithms for the 3D model of oblique photography can only restore single-pre cision data,which makes it difficult to meet the needs of different users.This paper proposes a reversible watermarking algo-rithm for 3D model of oblique photography that allows for controlled data precision recovery.Firstly,taking the advantage of the global stability of the mean angle between vertex normals,the feature points and non-feature points are divided for the 3D mod-el.Secondly,each feature point is taken as the center and grouped based on the ratio of its distance to non-feature points.Final-ly,the unique feature point in each group is taken as the origin to construct a spherical coordinate system,with the radius of the coordinate system serving as the carrier of the watermark information.Watermark information is embedded at different positions in the coordinate system.The experimental results show that watermarks can be extracted from different positions to recover data with different precision,so as to achieve controllable precision of data,and have good robustness to conventional attacks on oblique photography 3D models.