Patent ID: 7557907

Claim:
An object-detection device for a vehicle comprising: a transmission-and-reception device which irradiates electromagnetic waves across specified angles along the horizontal and vertical directions around a present vehicle at predetermined intervals and receives reflected electromagnetic waves from an object which exists around the present vehicle; a reflection point calculation device which calculates reflection points on the surface of the object where the electromagnetic waves irradiated from the transmission-and-reception device are reflected; a segment setting device which recognizes that mutual reflection points whose distance of each electromagnetic wave is less than a first predetermined value are exist on the same segment; a median point calculation device which calculates a median point of the segment; and a relative speed calculation device which calculates a relative speed of the present vehicle to the object based on the median point, wherein the relative speed calculation device eliminates a calculation result of the relative speed in the car width direction, with respect to the reflection points calculated based on the electromagnetic waves which are irradiated to the most downward direction in the specified angle in the vertical direction, in case that the number of difference between the reflection points in the current processing and the reflection points in the previous processing is equal to or greater than a predetermined number.