This peper presents an improving algorithm of grayscale morphological operations based on the definition by umbra. The main idea of the algorithm is to represent grayscale structure element by its top-surface-set, iusted of its umbra. This greatly reduces the binary neibourhood connection numbers. An optical binary morphological architecture of an incoherent correlator with threshold device is used for optical implementation, while spatial digital coding method is used to extend the 2D system to limited 3D operations.