Image data is processed by a low level feature detection processor that extractslow level features from an image. This is accomplished by converting a matrix of image data into a matrix of orthogonalicons that symbolically represent the image scene using a predetermined set of attributes. The orthogonal icons serve as the basis of processing by means of a high level graph matching processor which employs symbolicscene segmentation, description, and recognition processing that is performed subsequent to the low level feature detection. This processing generates attribute graphs representative of target objects present in the image scene. High level graph matching compares predetermined attributed reference graphs to the sensed graphs to produce a best common subgraph between the two based on the degree of similarity between the two graphs. The high level graph matching generates a recognition decision based on the value of the degree of similarity and a predetermined threshold. The output of the high level graph matching provides data from which a target aimpoint is determined, and this aimpoint is coupled as an input to a missile guidance system that tracks identified targets.
SCENE RECOGNITION SYSTEM AND METHOD EMPLOYING LOW AND HIGH LEVEL FEATURE PROCESSING