Research on Machine Vision-based Reading Method for Pointer Meters

Because industrial wireless technology has been widely used today, using image information to read traditional pointer meters accurately has a wide range of practical significance. Although there are many image processing methods to achieve the automatic measurement of the meter, these methods have varying degrees of impairment in terms of reading speed, accuracy and robustness. This paper proposes a novel method on the calibration of the meter center, because the grayscale images has an obvious difference of gray value inside and outside the instrument dial, based on energy minimization principle, the center and radius information that leads the energy function down to its minimum can be iterated to strike. This method takes full advantage of the image gray level information of the instrument, and takes small disturbances by local area noise so that it gives accurate results of calibration.