Abstract: A method and apparatus for data encoding and optical recognition of encoded data includes generating symbols that represent data using angles (rather than linear dimensions as used for conventional bar codes). One embodiment uses spirals isocurves. Another uses parabolas isocurves. Methods for visually depicting such symbols, including symbols having gray values are disclosed. Methods for machine-based detection and decoding of such symbols regardless of their orientation relative to the machine is also disclosed.

Abstract: A method and apparatus for data encoding and optical recognition of encoded data includes generating symbols that represent data using angles (rather than linear dimensions as used for conventional bar codes). One embodiment uses spirals isocurves. Another uses parabolas isocurves. Methods for visually depicting such symbols, including symbols having gray values are disclosed. Methods for machine-based detection and decoding of such symbols regardless of their orientation relative to the machine is also disclosed.

Abstract: The invention concerns an apparatus for detecting sudden changes of a feature in a region of an image that is divided into discrete picture elements, the feature being represented by complex valued signals, one for each picture element, the signal phase representing the feature class and the signal magnitude representing the certainty in the feature assertion. The apparatus includes a first unit (3) for providing the complex valued signals (10) within the region and at least a second unit for providing at least two collections of complex valued multiplication factor signals (11, 12, 13) that corresponds to the complex valued signals.