Object recognition in visually complex environments: an architecture for locating address blocks on mail pieces

A method of recognizing an object of interest in a complex visual environment is described. Motivated by the problem of finding the destination address block on a piece of mail, a general framework for coordinating a collection of specialized image analysis tools is described. The resulting system can deal with a wide range of environments: from those having a high degree of global spatial structure (e.g. mail envelopes which conform to specifications) to those with no structure (e.g. magazines with randomly pasted address labels). The problem-solving architecture accounts for uncertainty in the imaging environment by using the blackboard model. The system consists of several specialized tools and a control structure so that the tools are opportunistically invoked and coordinated. Its performance on an image database of difficult cases is described