A system and method are provided for uncued discrimination of a bated spatial pattern in an image electronically rendered as a frame of image data points. A reference unit establishes a general dictionary of predefined multi-dimensional reference functions, and a candidate detection unit pre-screens the frame of image data points to identify therein at least one candidate grouping of image data points collectively indicative of a predetermined spatial pattern. A sparse approximation unit coupled to the candidate detection and reference units computes for each candidate grouping an optimal reference function defined with respect to the general dictionary. The optimal reference function of each candidate grouping is projected onto a corresponding portion of the image data frame defined thereby. Each projected portion is extracted from the image data frame to leave a residual image data frame which, during iterative execution, provides the image data frame for the immediately succeeding iteration.