The invention discloses a scanning line
processing based automatic reading method for a pointer instrument. The method comprises the steps of firstly performing illumination
processing on an original image by adopting a single-scale
Retinex algorithm, binarizing the image, then extracting characteristic pixel points by a row scanning line
processing based method, performing Hough conversion on the characteristic pixel points to detect a straight line of a pointer, and finally calculating a read number by adopting an angle method, wherein the row scanning line processing based method refers to a method for scanning each row in the image, extracting continuous segments in the row, searching for the continuous segments with the lengths smaller than or equal to the
line width of the pointer and taking the
line segment midpoints of the continuous segments as the characteristic pixel points. According to the method, due to the adoption of the
Retinex algorithm, the influence of non-uniform illumination on subsequent algorithms can be reduced; and due to the adoption of the row scanning line processing based method, the number of pixel points participating in Hough conversion can be reduced, thereby reducing the calculation amount.