Patent ID: 7209582

Claim:
A coin discriminating method comprising steps of irradiating a surface of a coin with light, photoelectrically detecting light reflected by the surface of the coin, producing detected pattern data of the surface of the coin, binarizing corresponding reference pattern data so that “1” is assigned to pixel data having a signal intensity level equal to or higher than a predetermined signal intensity level and “0” is assigned to pixel data having a signal intensity level lower than the predetermined signal intensity level to produce reference bright portion pattern data consisting of “1” pixel data and reference dark portion pattern data consisting of “0” pixel data, extracting, based on the thus produced reference bright portion pattern data and reference dark portion pattern data, bright portion pattern data consisting of pixels corresponding to pixels included in the reference bright portion pattern data and dark portion pattern data consisting of pixels corresponding to pixels included in the reference dark portion pattern data from the detected pattern data, averaging signal intensity levels of the pixels included in the bright portion pattern data to calculate a bright portion data signal intensity average value, averaging signal intensity levels of the pixels included in the dark portion pattern data to calculate a dark portion data signal intensity average value, calculating a difference between the bright portion data signal intensity average value and dark portion data signal intensity average value, comparing it with a threshold value of coins of a corresponding denomination among threshold values defined for each denomination, and discriminating that a damage level of the surface of the coin is equal to or lower than a predetermined level when the difference between the bright portion data signal intensity average value and dark portion data signal intensity average value is equal to or larger than the threshold value and discriminating that the surface of the coin is damaged to higher than the predetermined level when the difference between the bright portion data signal intensity average value and dark portion data signal intensity average value is smaller than the threshold value.