Patent ID: 8620613

Claim:
A sensor diagnostic apparatus for diagnosing a sensor among a plurality of sensors, each of said plurality of sensors identifying an object and outputting acquired identification data of the identified object, said sensor diagnostic apparatus comprising: a moving object counter counting, in accordance with identification data acquired by the plurality of sensors in a predefined time period, a first local number of moving objects of which the identification data are acquired by a first sensor and a second sensor near the first sensor, and a second local number of moving objects of which the identification data are acquired by the first sensor and a third sensor near the first sensor, the first, second and third sensors being stationary; a reference value storage storing a first preset reference value for the first sensor and the second sensor; and a second preset reference value for the first sensor and the third sensor; and a comparator comparing a first value derived from the first local number to the first preset reference value, and a second value derived from the second local number to the second preset reference value, to determine that the first sensor is in error when a first difference between the first value and the first preset reference value exceeds a first predefined threshold value, and a second difference between the second value and the second preset reference value exceeds a second predefined threshold value.