| 摘要 |
An optical character reader distinguishes between black and white image signals by comparing a center reader with readings from surrounding areas. Variations on the surface of a paper bearing the image can add or subtract values so that the comparison may be in error. The invention overcomes the problem by using logic circuits to add, subtract and compare signals out of a mask in order to improve the accuracy of the comparison between the center reading and the readings from the surrounding areas. |
