Digital Watermark Detection in Visual Multimedia Content

Digital watermarking has been proposed as a technology to ensure copyright protection by embedding an imperceptible, yet detectable signal in visual multimedia content such as images or video. Watermark detection is an integral component of a watermarking system. This cumulative thesis addresses watermark detection problems in important application domains such as scalable multimedia, raw/demosaicked digital camera images, and 2D vector graphics with a distortion constraint. Generally, we rely on spread-spectrum watermark embedding and aim to improve performance of the system on the receiving side by taking into account peculiarities of the embedding domain and host signal modelling. A watermarked, scalable multimedia bitstream can be decoded in several quality and resolution layers to meet the demand of different devices. The watermark should be detectable in each layer, with increased detection performance in higher layers, yet without impairing the coding efficiency. We investigate watermarking of scalable JPEG2000, H.264/SVC and MZ-EZBC bit streams. A system for watermarking the raw image sensor data is constrained by the processing resources of the camera. We implement a spatial-domain embedding in camera firmware and propose a watermark detector exploiting the structure of the interpolated, demosaicked image. The computational effort for blind, spread-spectrum watermark detection is analyzed including the determination of the detection threshold and accuracy versus runtime trade-offs for the parameter estimation of the host signal model. We propose two novel detectors with runtime efficiency in mind that show competitive detection performance with state-of-the-art blind watermarking detection approaches. A novel watermark detector based on a joint statistical model for color images is proposed. Further, we investigate watermarking in the dual-tree complex wavelet domain and study the security of several quantization-based watermarking schemes. Digitale Wasserzeichen wurden als eine technische Lösung zum Schutz von Urheberrechten vorgeschlagen. Dabei wird ein nicht wahrnehmbares, jedoch detektierbares Signal in visuelle