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.

Abstract: The invention concerns an apparatus for determining the degree of variation 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 unit (3) for providing the complex valued signals (8) within the region and complex valued multiplication factor signals (9) corresponding to the complex valued signals. In a first summation unit (4), a first sum signal is generated by the magnitude products of the signals (8) and corresponding multiplication factor signals (9), and a second sum signal is generated by the complex valued scalar products of the signals (8) and corresponding complex conjugate of the multiplication factor signals.

Abstract: The invention concerns an apparatus for determining the degree of consistency of a feature in a region of an image that is divided into discrete picture elements, the feature being represented by vector valued signals, one for each picture element, the vector direction describing the feature class and the vector magnitude describing the certainty in the feature assertion. The invention is characterized by a first unit (4) for weighted summation of the vectors in the region after predetermined rotations thereof, a second unit (5) for weighted summation of the magnitudes of the vectors in the region, and a norming unit (6) for norming the output signal from the first summation unit with respect to the sum of the output signal from the second summation unit and a reference signal (FIG. 2).