To automatically read a value that an analog meter indicates by image processing and to provide digital signals suitable for computer management.

Initialization (setting of the rotation center of a pointer, a needle movable area and the scale information of a dial) is performed, the images of the needle movable area are respectively extracted from a reference image and a measurement image and the two extracted images are transformed by using polar coordinates with the rotation center as a reference and respectively transformed to the images linearly indicating the rotation angle of the pointer. The rotation angle of the pointer is obtained on the basis of the two images after polar coordinate transformation, and the obtained rotation angle is correlated to the scale information to obtain the indication value of the pointer of the measurement image.

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