Application constraints in the design of an automatic reading device for analog display instruments

An analysis system design based on experience with a successful application in the field of inspection and calibration of an analog display measuring instrument is presented in this paper. First the measuring instrument is divided into its primitiva, defining the a priori known parameter of the primitiva: shape, relative position and size. According to the shape of the primitiva pattern recognition algorithms are used to detect the primitiva in intensity images. These independent detection algorithms are then grouped into a detecting order with respect to efficiency. Following a discussion of the general design of the detecting algorithm, specific constraints of the application and the industrial environment are considered in order to refine the general design to an applicable and efficient device by modifying both hardware and software configuration depending on the given constraints. Finally, results of the implementation of the algorithm and the constructed image acquisition device are discussed