RAPID CALCULATION OF IMAGE MOMENTS USING OPTICAL PROJECTIONS.

The geometrical moments of a two-dimensional (2-D) image scene are often desired because they can be combined to produce image features that have attractive invariance properties (e. g. invariance to translation, rotation and spatial scale). The authors present a novel architecture for the calculation of the 2-D geometrical moments. The key attributes of the approach are speed (calculation of all moments can occur in a time on the order of 10 mu m) and flexibility (the system operates on an incoherently illuminated scene without requiring any kind of spatial light modulation or 2-D detector). The method is based on the measurement of several image projections (i. e. , line integrals), digital calculation of the 1-D moments of these projections and combination of the values of these 1-D moments to calculate the values of the 2-D image moments.