Image Type Water Meter Readings Identification Method

With the development of information society, image processing and machine vision is widely applied to all walks of life. All trades and professions management tool converts to automation or semi- automation from manual work. In this paper, we propose a method for water meter reading recognition, that is to say, computer reading substituting for manual reading in the past, can improve efficiency and save labor cost, and it has extensive academic and utility value.The work including:(1) This paper introduces arithmetic for image pre-processing. First, because of illumination, the image intensity is not uniform. The classic binarization algorithms such as Ostu algorithm and Bersen algorithm can not extract object well, so we use S.D.Yanowitz algorithm which interpolates the image grey by gradient imformation. Then it can get water meter frame information by horizontal and vertical projection, and extract line by improved Hough transform. Finally, the image can be corrected by affine transform.(2) This paper presents a step wise refinement strategy for digit character location. First, it can use a priori knowledge for approximate location. Second, morphologic enhancement and connected component filter make location more precisely. At last, the tangent rectangle can be solved by projection method, and can be differentiated between complete character and half character.(3) This paper researches on a digit character recognition method that is gliding template matching based on improved Hausdorff distance. Using Hausdorff distance in multi-fractal theory calculates the similarity between image and template, and improves the arithmetic's stability. In the process of the half digit character recognitions, the paper proposes sliding template concept, solves the problem that it has no uniqueness shape. Experiment proves the recognition rate of the arithmetic meets the practical need.