Object detection device, object detection method, and program

An object detection device comprising:

• an acquisition unit that acquires intensity of a direct wave at a second transmission and reception unit among a plurality of transmission and reception units that allow transmission and reception of an ultrasonic wave, the direct wave being directly received by the second transmission and reception unit and being an ultrasonic wave transmitted by a first transmission and reception unit among the plurality of transmission and reception units, and intensity of a reflected wave received by the first transmission and reception unit, the reflected wave being a reflected wave that is the ultrasonic wave transmitted from the first the transmission and reception unit being reflected from an object;
• and
• a detection unit that calculates an air-absorption attenuation coefficient using the ultrasonic wave on the basis of the intensity of the direct wave, and detects the object on the basis of the air-absorption attenuation coefficient and the intensity of the reflected wave,
• wherein
• in a case where the intensity of the direct wave is equal to or less than a second threshold value, the detection unit does not determine whether or not the object is present, and
• the second threshold value is not changed even if the air-absorption attenuation coefficient is changed.

An object detection method executed in an object detection device, the object detection method comprising:

• a step of acquiring intensity of a direct wave at a second transmission and reception unit among a plurality of transmission and reception units that allow transmission and reception of an ultrasonic wave, the direct wave being directly received by the second transmission and reception unit and being an ultrasonic wave transmitted by a first transmission and reception unit among the plurality of transmission and reception units, and intensity of a reflected wave received by the first transmission and reception unit, the reflected wave being a reflected wave that is the ultrasonic wave transmitted from the first the transmission and reception unit being reflected from an object;
• and
• a step of calculating an air-absorption attenuation coefficient using the ultrasonic wave on the basis of the intensity of the direct wave, and detecting the object on the basis of the air-absorption attenuation coefficient and the intensity of the reflected wave,
• wherein
• the step of acquiring acquires the intensity of the direct wave for each of the plurality of the transmission and reception units, and
• the step of calculating calculates an average value of the intensities of a plurality of the direct waves, and calculates the air-absorption attenuation coefficient on the basis of the average value.

A program stored on a non-transitory computer readable medium that causes a computer to function as

• an acquisition unit that acquires intensity of a direct wave at a second transmission and reception unit among a plurality of transmission and reception units that allow transmission and reception of an ultrasonic wave, the direct wave being directly received by the second transmission and reception unit and being an ultrasonic wave transmitted by a first transmission and reception unit among the plurality of transmission and reception units, and intensity of the reflected wave received by the first transmission and reception unit, the reflected wave being a reflected wave that is the ultrasonic wave transmitted from the first the transmission and reception unit being reflected from an object, and
• a detection unit that calculates an air-absorption attenuation coefficient using the ultrasonic wave on the basis of the intensity of the direct wave, and detects the object on the basis of the air-absorption attenuation coefficient and the intensity of the reflected wave,
• wherein
• the acquisition unit acquires the intensity of the direct wave for each of the plurality of the transmission and reception units, and
• the detection unit calculates an average value of the intensities of a plurality of the direct waves, and calculates the air-absorption attenuation coefficient on the basis of the average value.