New patents are issued by the USPTO on Tuesdays. Both of today's Spotlight Patents concern aspects of digital watermarking and both are assigned to Thomson (FR). The first of today's patents addresses techniques for watermarking a three-dimensional object. Today's second patent addresses techniques for increasing the strength of phase-based watermarking of an audio signal.
9,922,392, "Method for watermarking a three-dimensional object," assigned to Thomson Licensing (FR).
A method for watermarking a three-dimensional object is disclosed. The three-dimensional object is represented by a mesh. A mesh comprises a plurality of vertices. The method further comprises computing an original thickness signature for said mesh from a plurality of thickness values, wherein a thickness value is computed for a vertex of the mesh; determining a target thickness signature, wherein the target thickness signature is a function of a watermark payload and of the original thickness signature; and modifying a position of at least one vertex of the mesh wherein a thickness signature computed for the modified mesh reaches the target thickness signature and wherein a distortion constraint between the mesh and the modified mesh is satisfied. A method for detecting a watermark in a three-dimensional object, a three-dimensional object carrying a watermark and, devices for implementing the methods are further disclosed.
9,922,658, "Method and apparatus for increasing the strength of phase-based watermarking of an audio signal," assigned to Thomson Licensing (FR).
A challenge of audio watermarking systems in which an acoustic path is involved is the robustness against microphone pickup in case of surrounding noise. The strength of phase-based watermarking is increased by determining a masking threshold for a current frequency bin in a frequency/phase representation changing the phase based on that masking threshold and an allowed phase change value, calculating an allowed magnitude change value for the current frequency bin and calculating from an audio quality level value a magnitude change scaling factor for the magnitude change value, and increasing its magnitude accordingly.