A Novel Scale Recognition Method for Pointer Meters Adapted to Different Types and Shapes

Nowadays plenty of pointer meters are used in the field of chemical industry and electrical power system. To avoid reading their indication manually, many algorithms based on computer vision have been proposed to read pointer meters automatically. These methods, however, are limited to meters whose scales are uniform, and their accuracy is vulnerable to the error in the recognition of a meter's center. In this paper, a novel automatic reading algorithm of pointer meters based on scale seeking is proposed to overcome the weaknesses of the existing methods. Differing from the popular angle-based methods, we obtain the indication of the meter by comparing the distances between the peak of pointer and its nearest scales. The position and values of all scales can be automatically acquired and inferred by using our scale seeking and value inference algorithms, which is independent of any prior information in a database. Experiments prove that the algorithm can be applied to both meters with uniform or non-uniform scales effectively.