Patent ID: 8193820

Claim:
An occupant detection system comprising: a capacitive sensor that generates a weak electric field between an electrode arranged inside a vehicle seat and a vehicle body, and that outputs current or voltage according to magnitude or change of the weak electric field; and an electronic control unit that determines an OFF state when value of the current or voltage from the capacitive sensor is lower than a predetermined determination threshold, and that determines an ON state when the value of the current or voltage from the capacitive sensor exceeds the determination threshold, wherein the OFF state prohibits deployment of an air bag, wherein the ON state permits the deployment of the air bag, wherein the electronic control unit includes: an evaluation block that calculates a time ratio of the OFF state and the ON state within a predetermined time period, wherein the OFF state and the ON state are determined by the electronic control unit; and a correction block that changes the determination threshold to a predetermined value according to the time ratio calculated by the evaluation block.