点云投影采样及新型大容量三维信息隐藏方法
Projection Sampling of Point Clouds and a Novel High-Capacity 3D Information Hiding Method
-
摘要: 针对现有三维信息隐藏算法中顶点同步时间长和不稳定的问题, 提出一种三维点云投影采样策略. 将所有顶点垂直投影至 XOY 平面, 通过调节投影面分辨率控制采样顶点数, 规则存取采样点达到顶点同步. 利用该点云投影采样策略, 提出了一种新型三维点云信息隐藏方法, 可以同时将秘密数据嵌入到顶点的 Z 坐标和 3 个彩色分量中.由于在嵌入时不改变 X 和 Y 轴坐标值, 能够在大容量嵌入的同时保证顶点同步的稳定性. 该隐藏方法在秘密数据提取时不需要载体模型, 是一种盲提取方法. 在 Matlab 软件环境下, 利用公开的几种常用动物模型和一种人脸的三维模型数据为载体进行了大量仿真实验. 实验结果表明, 所提方法是一种大容量隐藏方法, 嵌入容量高达 5 bpv; 其不可感知性好, 最大嵌入容量时 PSNR 最低为 51 dB; 可以完全抵抗重排序攻击; 单独或同时对 X 和 Y 轴进行坐标平移、尺度缩放时提取水印的相关系数都几乎为 1; 能够抵抗剪切比例小于 15%的剪切攻击(相关系数大于 0.75); 对加性噪声也有一定的抵抗能力.Abstract: Aiming at the problems of long synchronization time and instability issues in the existing 3D information hiding algorithms, a novel 3D projection sampling strategy for 3D point cloud data is proposed. Projecting all vertices onto the XOY plane, and the number of sampled vertex is controlled by adjusting the resolution of the projection surface, and the vertex synchronization is realized by regular access to the sampled points. Based on this strategy, a novel information hiding approach is proposed for 3D point cloud data. Secret data is embedded into the Z-axis coordinate and the three color components at the same time. Due to the fixed X and Y-axis coordinates, the stability of vertex synchronization is ensured when large-capacity data is embedded. The host model is not needed when extracting the secret data, so it is a blind extraction. Substantial simulation experiments are conducted through Matlab by using public 3D data, such as several animals and a human face. The experimental results show that the proposed 3D information hiding method based on projection sampling is a high-capacity hiding technique with the embedding capacity of up to 5 bits per vertex (bpv). The method exhibits excellent imperceptibility, with a minimum PSNR of 51 dB at maximum embedding capacity. It can completely resist to reordering attacks. The correlation coefficients are nearly 1 for extracting watermarks from individual or simultaneous coordinate translations and scale changes along the X and Y axes. It can resist cropping attacks with cropping ratios less than 15% (correlation coefficient greater than 0.75), and exhibits a certain level of resilience to additive noise.