Watermark systems and methods
A number of novel watermarking applications, and improvements to watermarking methods, are disclosed. Included are techniques for encoding printed circuit boards and street signs with watermarks, deterring credit card fraud and controlling software licensing using watermarks, registering collectibles via watermarks, encoding the margins of printed pages with watermarks, and using watermarks to convey extra information in video by which fidelity of the rendered video may be improved.One particular arrangement is a method in which a PDA, wristwatch, or other portable device with a display screen presents an image that depicts a proprietor of the device, and also includes a machine-readable identifier (e.g., a watermark or barcode). This image is sensed by a separate device, such as a webcam or a camera-equipped cell phone. The sensing device can then take an action based on the identifier (e.g., linking to an email account or to a web site that corresponds to the person depicted on the display screen).
1. A method, employing an image sensor apparatus, and a separate portable device with a display screen, comprising using the image sensor apparatus to capture a representation of a graphic presented on the display screen of the portable device, and decoding said captured representation to obtain plural-bit data steganographically encoded in said graphic.
2. The method of claim 1 wherein the graphic comprises an image of a person.
3. The method of claim 2 wherein the graphic comprises an image of a proprietor of the portable device.
4. The method of claim 1 wherein the screen of the portable device is also used to display the current time.
5. The method of claim 4 wherein the portable device is a wristwatch.
6. A method, employing an image sensor apparatus, and a separate portable device with a display screen, comprising using the image sensor apparatus to capture a representation of a graphic presented on the display screen of the portable device, the graphic including a depiction of a proprietor of the portable device, and decoding plural-bit machine readable information also represented on the display screen.
7. A method of conveying plural bit information to a first device from a second, portable device, comprising:
receiving a steganographically encoded graphic, said steganographic encoding representing plural bit information;
displaying said encoded graphic on an electronic display screen of the second device; and
presenting said display screen to the first device for optical capture.
8. The method of claim 7 that includes generating optical capture data in the first device, and decoding the plural bit information therefrom.
9. The method of claim 7 , wherein the graphic comprises an image of a proprietor of the second device.