用于头戴式虚拟现实眼镜的视频水印

头戴式虚拟现实眼镜可以将人对外界的视觉封闭,使观看者产生沉浸于虚拟环境中的感觉。为了实现这一效果,头戴式虚拟现实眼镜会将广角镜片放置在使用者的眼睛前,使得视频画面聚焦。由于广角镜片的使用会对画面产生枕形畸变,从而影响观看的效果;因此播放的视频画面要先经过桶形变换以抵消广角镜片的影响。此时使用者可以拷贝经过桶形变换的视频,从而盗版该视频。在这种情况下,视频的版权信息不仅需要在原始视频中验证,还需要在经过桶形变换后的视频中验证。提出了一种用于头戴式虚拟现实眼镜的视频水印方案;该方案使用基于扩频的水印嵌入方法,将数字水印模板嵌入到视频帧的中频中。对于遭受了桶形变换的视频帧而言,首先提出了一种桶形变换参数估计方法;然后对遭受了桶形变换的视频进行枕形变换以期恢复出桶形变换,前的画面;最后,对恢复的视频帧和水印模板进行相关性计算,以检测该视频中是否含有水印。实验结果表明,可以正确地从遭受桶形变换的视频帧中检测出已嵌入的水印,说明可以用于头戴式虚拟现实眼镜中的视频的版权保护。

Video Watermarking for Virtual Reality Head-mounted Glasses

Head-mounted virtual reality glasses (HMCRG) closure the outside vision. It makes the viewer immerse in the virtual environment. To achieve this effect, the HMCRG will place a wide-angle lens in front of the viewer"s eyes, making the video into focus. The pincushion distortion will be introduced by wide-angle lens. Therefore, the video must be pre-warped with barrel distortion to cancel this distortion. Noting that the viewer might record the distorted video and misuse this content. In such a scenario, the ownership of the video should be verified not only on the original views, but also on the distorted view. In this paper, a video watermarking scheme for HMCRG is proposed. A spread spectrum based method is used to embedding watermark into the original video frame. In order to detect watermark from the warped frame with barrel distortion, an estimation method of the barrel distortion is proposed. Then, pincushion distortion is used to restore the pre-warped frame to original frame. Finally, a correlation computing is used to detect whether the frame has been watermarked. The encouraging experimental results demonstrate that the proposed watermarking scheme can be used to protect the copyright of the video for HMCRG.