CLASS OF TRANSFORMS INVARIANT UNDER SHIFT, ROTATION, AND SCALING

We introduce a new class of nonreversible transform that is simultaneously invariant under shift, rotation, and scaling. The algorithm is based on a general transformation where the kernel itself contains the functionto be transformed. Thus the invariances are achieved by a kind of self-mapping. Preprocessing of the inputsignal, such as determination of the centroid or coordinate transformation, is not necessary. The transformcan be used for multidimensional data. Fast implementation is possible by look-up tables. © 1990 Optical Society of America.