Flexible automatic visual inspection based on the separation of detection and analysis

Since the mid-1970s, a large number of visual inspection systems and algorithms for industrial inspection have been developed. To be acceptable in industry, vision systems must be inexpensive, within the speed of the production-line flow, and very accurate. Furthermore the system should be flexible enough to accommodate changes in products. This flexibility can only be achieved by a modular concept that allows a quick and inexpensive adaption of the inspection process to changes in production. This paper presents a concept for visual inspection where the detection of primitives is separated from the model-based analysis process. Existing pattern recognition software is re-used in the detection stage and therefore the use of any detection algorithm is possible without changing the analysis process. The visual inspection of analog display measuring instruments serves as a demonstration of this concept. Results concerning time, accuracy, and reliability for the specific inspection task are given at the end of the paper