Object detection device, object detection method, and recording medium
An object detection device includes an acquisition circuit, a calculation circuit, and an estimation circuit. The acquisition circuit acquires elapsed times from when an ultrasonic wave is transmitted from a transmission microphone to when reception microphones each receive the ultrasonic wave. The calculation circuit calculates a wind speed on the basis of the elapsed times acquired by the acquisition circuit. The estimation circuit estimates a vehicle state on the basis of the wind speed calculated by the calculation circuit.
1 . An object detection device configured to be mounted on a vehicle, the object detection device comprising:
an acquisition circuit which, in operation, acquires elapsed times from when an ultrasonic wave is transmitted from a transmission microphone to when reception microphones each receive the ultrasonic wave;
a calculation circuit which, in operation, calculates a wind speed based on the elapsed times acquired by the acquisition circuit; and
an estimation circuit which, in operation, estimates a traveling direction of the vehicle based on the wind speed calculated by the calculation circuit.
2 . The object detection device according to claim 1 , wherein a number of the reception microphones is a multiple of 2.
3 . The object detection device according to claim 1 , wherein the reception microphones are provided on a side face of a vehicle, the reception microphones being arranged in a horizontal direction of the vehicle while interposing the transmission microphone between the reception microphones.
4 . The object detection device according to claim 1 , wherein the reception microphones are provided on a front face of a vehicle, the reception microphones being arranged in a vertical direction of the vehicle while interposing the transmission microphone between the reception microphones.
5 . The object detection device according to claim 1 , wherein
a number of the reception microphones is a multiple of 4, and
the reception microphones are disposed to surround the transmission microphone.
6 . The object detection device according to claim 1 , wherein the calculation circuit which, in operation, performs calculation of the wind speed by using a time difference between the elapsed times acquired by the acquisition circuit.
7 . The object detection device according to claim 1 , further comprising a transmission control circuit which, in operation, controls transmission of ultrasonic wave performed by the transmission microphone in accordance with the traveling direction of the vehicle estimated by the estimation circuit.
8 . The object detection device according to claim 1 , further comprising a reception control circuit which, in operation, controls reception of ultrasonic wave performed by the reception microphones in accordance with the traveling direction of the vehicle estimated by the estimation circuit.
9 . An object detection method by an object detection device configured to be mounted on a vehicle, the method comprising:
acquiring elapsed times from when an ultrasonic wave is transmitted from a transmission microphone to when reception microphones each receive the ultrasonic wave;
calculating a wind speed based on the elapsed times acquired by the acquiring; and
estimating a traveling direction of the vehicle based on the wind speed calculated by the calculating.
10 . The object detection method according to claim 9 , wherein a number of the reception microphones is a multiple of 2.
11 . The object detection method according to claim 9 , wherein the reception microphones are provided on a side face of a vehicle, the reception microphones being arranged in a horizontal direction of the vehicle while interposing the transmission microphone between the reception microphones.
12 . The object detection method according to claim 9 , wherein the reception microphones are provided on a front face of a vehicle, the reception microphones being arranged in a vertical direction of the vehicle while interposing the transmission microphone between the reception microphones.
13 . The object detection method according to claim 9 , wherein
a number of the reception microphones is a multiple of 4, and
the reception microphones are disposed to surround the transmission microphone.
14 . The object detection method according to claim 9 , wherein the calculating of the wind speed is performed by using a time difference between the elapsed times acquired by the acquiring.
15 . The object detection method according to claim 9 , further comprising controlling transmission of ultrasonic wave performed by the transmission microphone in accordance with the traveling direction of the vehicle estimated by the estimating.
16 . The object detection method according to claim 9 , further comprising controlling reception of ultrasonic wave performed by the reception microphones in accordance with the traveling direction of the vehicle estimated by the estimating.
17 . A non-transitory computer-readable recording medium on which programmed instructions are recorded, the programmed instructions causing a computer configured to be mounted on a vehicle to execute processing, the processing comprising:
acquiring elapsed times from when an ultrasonic wave is transmitted from a transmission microphone to when reception microphones each receive the ultrasonic wave;
calculating a wind speed based on the elapsed times acquired by the acquiring; and
estimating a traveling direction of the vehicle based on the wind speed calculated by the calculating.
18 . The object detection device according to claim 7 , wherein:
the estimation circuit, in operation, further estimates a speed of the vehicle based on the wind speed calculated by the calculation circuit;
in a case that the traveling direction of the vehicle estimated by the estimation circuit is forward and the speed of the vehicle estimated by the estimation circuit is lower than a predetermined value, a transmission control circuit, in operation, reduces a wave number of the ultrasonic wave transmitted from the transmission microphone and reduces an output level of the ultrasonic wave; and
in a case that the traveling direction of the vehicle estimated by the estimation circuit is forward and the speed of the vehicle estimated by the estimation circuit is not less than the predetermined value, the transmission control circuit, in operation, increases the wave number of the ultrasonic wave transmitted from the transmission microphone and increases the output level of the ultrasonic wave.
19 . The object detection method according to claim 9 , further comprising:
estimating a speed of the vehicle based on the wind speed calculated by the calculating;
reducing a wave number of the ultrasonic wave transmitted from the transmission microphone and an output level of the ultrasonic wave, in a case that the traveling direction of the vehicle by the estimating is forward and the speed of the vehicle by the estimating is lower than a predetermined value; and
increasing the wave number of the ultrasonic wave transmitted from the transmission microphone and the output level of the ultrasonic wave, in a case that the traveling direction of the vehicle by the estimating is forward and the speed of the vehicle by the estimating is not less than the predetermined value.