Method for automatically reading numerical value of universal single-pointer instrument of transformer substation

The invention provides an automatic numerical value reading method for a universal single-pointer instrument of a transformer substation, which belongs to the field of image processing, is a universal numerical value reading method for the single-pointer instrument, is simple and practical, and comprises the following steps of: 1, modeling a pointer image of the single-pointer instrument, constructing a preset bit template image and providing priori knowledge; step 2, inputting a to-be-recognized image, performing instrument positioning, realizing alignment of the to-be-recognized image and the preset bit template image, positioning the to-be-recognized image to a dial plate, and generating a mask image of the dial plate; step 3, performing rotation and size correction on the generated mask image, and adaptively adjusting the size on the premise of ensuring that the mask image has no pixel loss, so that the pointer is always matched at the 0 scale position; 4, the pointer is positioned, the approximate positi