Abstract: More accurate location of a buried utility conveyance (10) is obtained by first detecting, via a detector (34) the actual pattern of radiation (26, 28) of a locating signal impressed on the conveyance. The actual pattern of radiation is compared, by a processor (36) to each of a plurality of reference patterns stored in a database (38), each pattern representing the radiation for a conveyance having a known location. The processor selects the reference pattern that most closely the actual pattern and then provides an indication of the conveyance location associated with the selected reference pattern.

Abstract: A digital image signal is watermarked by locally changing geometric features of the image. The watermark consists of a pseudo-random, dense subset of image pixels, e.g., a pattern of lines (20). A number of significant image pixels (21,22,23), i.e., pixels which give the highest response to a predetermined processing operation, is determined and then moved (24) to the vicinity (&dgr;) of the line pattern. As a result of this “warping”, the majority of significant image pixels (21,22) is eventually located within the vicinity of the line pattern. At the receiver end, the most significant pixels of an input image are again determined. The image is a watermarked image if a statistically high percentage lies within the vicinity of the line pattern.

Abstract: A system for creating copy restrictive media is disclosed. The system comprises printing a first pattern of microdots (80) on a first set of documents and printing a second pattern of microdots (82) on a second set of documents. A first key code is associated with the first microdot pattern (80), which allows a copy machine to copy the first set of documents, and a second key code is associated with the second microdot pattern (82), which allows a copy machine to copy the second set of documents. This system allows individual copyright owner to insure that no one else is able to reproduce their copyrighted documents.

Abstract: An image processing apparatus and method for identifying a safe landing location on the surface of the moon or planets calculates local average brightness and brightness variance in a neighborhood of each image pixel based on a digital image data obtained with a camera and determines whether each pixel represents a level and flat area based on the local average brightness and brightness variance calculated for each pixel, thereby extracting a desirable landing site.