载体独立的抗屏摄信息膜叠加水印算法

Carrier-independent screen-shooting resistant watermarking based on information overlay superimposition

金融安全作为国家安全的重要组成部分,是经济平稳健康发展的重要基础。数字图像水印技术在金融信息安全方面发挥着巨大作用,其中,抗屏幕拍摄水印算法成为数字图像水印技术新的研究重点。如何兼顾水印图像的视觉质量和鲁棒性是抗屏幕拍摄鲁棒水印算法需要解决的重要问题。现有的水印方案一般通过对载体图像进行修改来实现水印不可见的目的,这种水印嵌入方式不具有普适性。为此,提出了一种新的基于深度学习的端到端抗屏幕拍摄鲁棒水印算法。作为端到端网络架构的一部分,编码器网络的输入是随机二进制字符串,经过网络训练后根据输入的水印信息生成相应的水印信息膜,可以附加在任意的载体图像上。使用数学方法模拟了屏幕拍摄过程中可能产生的失真,使得经过网络学习后的模型具有抵抗屏幕拍摄噪声的能力。增加了基于图像的恰可察觉差损失来进一步提升水印图像的视觉质量。此外,为了更灵活地平衡水印图像的视觉质量和鲁棒性,在训练阶段设计了一个嵌入超参数,通过改变嵌入超参数的大小,就可以得到适合不同场景的模型。为了验证所提算法的有效性,针对视觉质量和鲁棒性做了多种实验。实验结果表明,与目前的主流算法相比,使用所提算法生成的水印图像具有更好的视觉质量,并且在不同距离、不同角度、不同光照条件和不同设备的鲁棒性实验中均可以准确还原原始水印信息。

Financial security,an important part of national security,is critical for the stable and healthy development of the economy.Digital image watermarking technology plays a crucial role in the field of financial information security,and the anti-screen watermarking algorithm has become a new research focus of digital image watermarking technology.The common way to achieve an invisible watermark in existing watermarking schemes is to modify the carrier image,which is not suitable for all types of images.To solve this problem,an end-to-end robust watermarking scheme based on deep learning was proposed.The algorithm achieved both visual quality and robustness of the watermark image.A random binary string served as the input of the encoder network in the proposed end-to-end network architecture.The encoder can generate the watermark information overlay,which can be attached to any carrier image after training.The ability to resist screen shooting noise was learned by the model through mathematical methods incorporated in the network to simulate the distortion generated during screen shooting.The visual quality of the watermark image was further improved by adding the image JND loss based on just perceptible difference.Moreover,an embedding hyperparameter was introduced in the training phase to balance the visual quality and robustness of the watermarked image adaptively.A watermark model suitable for different scenarios can be obtained by changing the size of the embedding hyperparameter.The visual quality and robustness performance of the proposed scheme and the current state-of-the-art algorithms were evaluated to verify the effectiveness of the proposed scheme.The results show that the watermark image generated by the proposed scheme has better visual quality and can accurately restore the embedded watermark information in robustness experiments under different distances,angles,lighting conditions,display devices,and shooting devices.