WATERMARKING OF AN IMAGE MOTION SIGNAL

摘要

The present invention relates to a method for embedding a watermark (w) in an image motion signal (55). The invention describes a method for embedding a watermark (w) in a motion image signal (55) in the optical domain in several steps. Initially, the watermark, i.e. the information for embedding, is represented by a sequence of watermark samples. During embedding sharpness changing means (10) are applied to change the sharpness in response to the watermark samples, and thereby embedding the watermark in the motion image signal (55) in a simple and efficient manner in the optical domain. The sharpness changing can be implemented by various ways, e.g. by displacing a lens (10) slightly. A particular embodiment exploits a variable focus lens having a liquid lens operated by electro-wetting. Further, the present invention relates to a corresponding apparatus for embedding the watermark.