Obstacle warning apparatus

1. An obstacle warning apparatus used in a vehicle, cooperating with an obstacle sensor that detects an obstacle around the vehicle, the obstacle warning apparatus comprising:

an obstacle position specification section that specifies a position of an obstacle with respect to the vehicle based on a detection result by the obstacle sensor;

a warning determination section that determines whether a warning that reports an existence of the obstacle needs to be executed, based on the position of the obstacle specified by the obstacle position specification section;

a warning processing section that causes the warning to be executed to a driver when the warning determination section determines that the warning needs to be executed;

an overlap determination section that determines whether a vehicle range where the vehicle exists overlaps with a range where the obstacle exists, based on the position of the obstacle specified by the obstacle position specification section; and

a variation specification section that specifies a variation amount of the position of the vehicle,

wherein:

the position of the obstacle specified by the obstacle position specification section indicates a position of a detection point that is one point included in the obstacle;

the obstacle position specification section stores in a memory the position of the detection point with respect to the vehicle specified based on the detection result by the obstacle sensor, while updating the position of the detection point stored in the memory depending on the variation amount of the position of the vehicle to successively specify a relative position of the obstacle with respect to the vehicle;

the overlap determination section determines that the vehicle range overlaps with the range where the obstacle exists, when the position of the detection point stored in the memory exists within the vehicle range, the position of the detection point being updated in the memory depending on the variation amount of the position of the vehicle; and

the warning determination section determines that the warning about the obstacle does not need to be executed when the overlap determination section determines that the vehicle range overlaps with the range where the obstacle exists.

2. The obstacle warning apparatus according to claim 1 , wherein:

the overlap determination section estimates an error between the position of the obstacle specified by the obstacle position specification section and a position where the obstacle actually exists; and

the overlap determination section determines that the vehicle range overlaps with the range where the obstacle exists when a vehicle-width direction or a vehicle-back-and-forth direction of an overlap portion is equal to or greater than the error, the overlap portion in which the vehicle range overlaps with the range where the obstacle exists, the range where the obstacle exists.

3. The obstacle warning apparatus according to claim 1 , wherein:

the overlap determination section calculates a detection error range that is a range where the obstacle can exist actually against, as a basis, the position of the obstacle specified by the obstacle position specification section; and

when the vehicle range overlaps with a whole of the detection error range, the overlap determination section determines that the vehicle range overlaps with the range where the obstacle exists.

4. The obstacle warning apparatus according to claim 1 , wherein

when the position of the detection point specified by the obstacle position specification section is located within the vehicle range and separated from an outline of the vehicle range by a predetermined distance or greater, the overlap determination section determines that the vehicle range overlaps with the range where the obstacle exists.

5. The obstacle warning apparatus according to claim 1 , wherein:

the obstacle position specification section determines whether the a plurality of detection points stored in the memory are detection results that are each with respect to an identical obstacle;

when determining that the plurality of detection points stored in the memory are detection results that are each with respect to the identical obstacle, the obstacle position specification section stores the detection points to be associated with each other;

when a position of a detection point, which is stored in the memory and relative to the vehicle, satisfies a warning condition to determine that the warning needs to be executed, the warning determination section determines that the warning about the detection point needs to be executed; and

when the overlap determination section determines that the vehicle range overlaps with the range where the obstacle exists, based on at least one of the plurality of detection points associated with each other, the warning determination section determines the warning does not need to be executed with respect to all of the detection points associated with each other.

6. The obstacle warning apparatus according to claim 1 , wherein:

the obstacle sensor detects the obstacle which exists in a lateral region relative to the vehicle; and

the obstacle position specification section specifies the position of the obstacle that exists in the lateral region based on the detection result by the obstacle sensor.