A new metric for measuring the visual quality of video watermarks

In this paper we present an extension to the video watermarking scheme that we introduced in our previous work as well as a new objective quality metric for video watermarks. As the amount of data that today's video watermarks can embed into a single video frame still is too small for many practical applications, our watermarking scheme provides a method for splitting the watermark message and spreading it over the complete video. This way we were able to overcome the capacity limitations, but we also encountered a new kind of distortions that effects the visual quality of the video watermark, the so-called "flickering" effect. However we found that the existing video quality metrics were unable to capture the "flickering" effect. The extension of our watermarking scheme that is presented in this paper is able to reduce the "flickering" effect and thus improves the visual quality of the video watermark by using scene detection techniques. Further on we introduce a new quality metric for measuring the "flickering" effect, which is based on the well-known SSIM metric for still images and which we call "Double SSIM Difference". Finally we present our results of the evaluation of the proposed extension of the watermark embedding process, which was applied using the "Double SSIM Difference" metric.