Check-actuated control mechanisms – Including means to test validity of check – By testing material composition
Reexamination Certificate
1999-10-22
2001-10-23
Lillis, Eileen D. (Department: 3652)
Check-actuated control mechanisms
Including means to test validity of check
By testing material composition
C174S373000, C174S373000, C174S373000
Reexamination Certificate
active
06305523
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a coin discriminating apparatus capable of determining with high accuracy the denomination and authenticity of a coin by a simple process based on information on surface displacement irregularities of a stamp (strike) pattern on a coin surface. More particularly, the invention relates to a coin discriminating apparatus wherein a histogram of surface displacement irregularities information indicative of a stamp pattern on a surface of a coin is created as feature information and is collated with a histogram obtained beforehand with respect to a true coin (one of coins to be handled), thereby to identify the authenticity and denomination of the coin with high accuracy based on the stamp pattern on the coin surface.
2. Description of the Related Art
In vending machines, automatic teller machines (ATMs), etc., a coin discriminating apparatus is incorporated to determine the denomination and authenticity of coins, as a process preliminary to the calculation of the sum of inserted coins. This type of coin discriminating apparatus is generally designed to measure the outer diameter, thickness and weight of a coin and compare the measured values with previously obtained outer diameter, thickness and weight of a true coin (one of coins of different denominations to be handled) to determine the denomination of the coin, and nonauthentic coins are rejected. Among a diversity of coins, however, there are coins, for example, coins used in foreign countries, that should not be accepted but yet have features (outer diameter, thickness, weight) resembling those of true coins to be accepted, and such coins can be erroneously judged to be authentic.
Attempts have therefore been made to acquire, in the form of an image, information on surface displacement irregularities of a stamp pattern on a coin surface and recognize features of the image, thereby to identify the denomination of the coin. However, in cases where the features (pattern) of an image showing the stamp pattern on a surface of a coin to be discriminated are compared with those (pattern) of an image showing the stamp pattern of a true coin, it is necessary that a matching process be performed following the rotation of the image for comparison, or that an extra process such as Fourier transform be performed as needed. Thus, a complicated process is required for the discrimination of coins and the process consumes much time.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a coin discriminating apparatus wherein, to permit easy and reliable determination of the denomination and authenticity of a coin, information on surface displacement irregularities of a stamp pattern on a surface of a coin is acquired, features of the stamp pattern represented by the surface displacement irregularities information are obtained as a histogram of distribution of surface displacement irregularities over the entire surface of the coin, and the histogram is compared with a previously obtained histogram indicative of distribution of surface displacement irregularities of a true coin, to determine the denomination of the coin.
Specifically, the present invention utilizes the surface displacement irregularities information indicative of features of a stamp pattern on a surface of a coin, and is characterized in that the features of the stamp pattern on a coin surface are acquired exactly as a histogram of frequency distribution of surface displacement irregularities over the entire surface of the coin, thereby permitting easy and high-accuracy determination of the denomination and authenticity of the coin. The present invention is characterized in particular in that the denomination of a coin can be discriminated without the need to perform a complicated process such as rotation of the stamp pattern (image information) on the coin surface represented by the surface displacement irregularities information or complex mechanical manipulation of the coin for coin image registration with the stored image orientation.
According to one embodiment of the present invention, a sensor for obtaining information on surface displacement irregularities of a stamp pattern on a coin surface comprises a plurality of eddy current induction coils for respectively locally applying high-frequency electromagnetic field to a coin and collectively covering the entire surface thereof to induce eddy current in the coin, and impedance measuring means for detecting impedances of the eddy current induction coils that vary depending on the eddy current induced in the coin. Using the detected impedances as surface displacement irregularities information, distribution of the impedances over the entire surface of the coin is plotted in the form of a histogram showing the impedance along the abscissa and the numbers of eddy current induction coils along the ordinate, thereby acquiring features of the surface displacement irregularities.
Preferably, the eddy current induction coils are arranged on a plane in a rectangular grid form to constitute a coil array, and the coil array is arranged so as to face a surface of a coin.
According to another embodiment of the present invention, the sensor for obtaining information on surface displacement irregularities of a stamp pattern on a coin surface comprises a light source for diffusely illuminating a surface of a coin with light, and a plurality of optical sensors for detecting light rays which are reflected from the surface of the coin after being emitted from the light source. Using the intensities of the reflected light rays obtained by the optical sensors as the surface displacement irregularities information, distribution of the intensities of the reflected light rays over the entire surface of the coin is plotted in the form of a histogram showing the reflected light intensity along the abscissa and the numbers of optical sensors with a response in a specified range along the ordinate.
According to still another embodiment of the present invention, the aforementioned sensor comprises a light source for illuminating a surface of a coin with light, and an image sensor for acquiring an image of the surface of the coin illuminated by the light source. Using luminance signals in image signals obtained by the image sensor as the surface displacement irregularities information, distribution of the luminance signal levels over the entire surface of the coin is plotted in the form of a histogram showing the luminance signal level along the abscissa and the numbers of pixels with luminance levels in a specified range along the ordinate.
A coin discriminating apparatus according to a preferred embodiment of the present invention further comprises an eddy current induction coil for applying low-frequency electromagnetic field to a coin to induce eddy current therein, impedance measuring means for detecting an impedance of the eddy current induction coil that varies depending on the eddy current induced in the coin, and material determining means for comparing the detected impedance of the eddy current induction coil with an impedance obtained beforehand with respect to a true coin, to determine the material of the coin. The use of the material determining means makes it possible to further enhance the coin discrimination accuracy.
According to a preferred embodiment of the present invention, the coin discriminating apparatus may further comprise coin diameter measuring means for measuring the diameter of a coin based on the impedances of the eddy current induction coils detected when the coils are excited at high frequency, and/or coin thickness measuring means for measuring the thickness of the coin based on the impedances of the eddy current induction coils excited at high frequency. The coin diameter measuring means and the coin thickness measuring means each serve to enhance the coin discrimination accuracy.
Further, according to a preferred embodiment of the present invention, specified coils in the eddy current induction coil grid that
Davis Richard J.
House Larry J.
Japan Tobacco Inc.
Lillis Eileen D.
Tran Thuy V.
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