An object detection apparatus includes distance measuring devices and a hardware processor. The distance measuring devices are provided in a vehicle and emit ultrasonic waves. The distance measuring devices detect an object around the vehicle and obtain distance information indicating a distance to the detected object. The hardware processor determines a scene in which the vehicle is placed. The determination is performed on the basis of the distance information, vehicle speed information, an image of surroundings of the vehicle, and/or a location of the vehicle on a map. The hardware processor performs, on the basis of a scene determination result, setting of a high-sensitivity area where sensitivity for detecting the reflected waves is temporarily increased, a change of an emission interval of the ultrasonic waves, and/or a change of an emission sequence of the ultrasonic waves.

An object detection apparatus includes distance measuring devices and a hardware processor. The distance measuring devices are provided in a vehicle and emit ultrasonic waves. The distance measuring devices detect an object around the vehicle and obtain distance information indicating a distance to the detected object. The hardware processor determines a scene in which the vehicle is placed. The determination is performed on the basis of the distance information, vehicle speed information, an image of surroundings of the vehicle, and/or a location of the vehicle on a map. The hardware processor performs, on the basis of a scene determination result, setting of a high-sensitivity area where sensitivity for detecting the reflected waves is temporarily increased, a change of an emission interval of the ultrasonic waves, and/or a change of an emission sequence of the ultrasonic waves.

A wideband sonar receiver is provided that includes: a selectable bandpass filter adapted to filter a received sonar signal to produce a filtered signal and a correlator adapted to correlate the baseband samples with baseband replica samples to provide a correlated signal. In addition, the wideband sonar receiver may include a shaping filter to shape unshaped received pulses. Finally, a variety of sonar processing algorithms are described with regard to reducing clutter and interference, target detection, and bottom detection.

A wideband sonar receiver is provided that includes: a selectable bandpass filter adapted to filter a received sonar signal to produce a filtered signal and a correlator adapted to correlate the baseband samples with baseband replica samples to provide a correlated signal. In addition, the wideband sonar receiver may include a shaping filter to shape unshaped received pulses. Finally, a variety of sonar processing algorithms are described with regard to reducing clutter and interference, target detection, and bottom detection.

A distance measuring device includes a calculating section configured to calculate, based on phase information acquired by a first device and a second device, at least one of which is movable, a distance between the first device and the second device. The first device includes a first reference signal source and a first transceiver configured to transmit two or more first carrier signals and receives two or more second carrier signals using an output of the first reference signal source. The second device includes a second reference signal source configured to operate independently from the first reference signal source and a second transceiver configured to transmit the second carrier signals and receives the first carrier signals using an output of the second reference signal source. The calculating section calculates the distance based on a phase detection result obtained by reception of the first and second carrier signals.

A distance measuring device includes a calculating section configured to calculate, based on phase information acquired by a first device and a second device, at least one of which is movable, a distance between the first device and the second device. The first device includes a first reference signal source and a first transceiver configured to transmit two or more first carrier signals and receives two or more second carrier signals using an output of the first reference signal source. The second device includes a second reference signal source configured to operate independently from the first reference signal source and a second transceiver configured to transmit the second carrier signals and receives the first carrier signals using an output of the second reference signal source. The calculating section calculates the distance based on a phase detection result obtained by reception of the first and second carrier signals.

A distance measuring device includes a calculating section configured to calculate, based on phase information acquired by a first device and a second device, at least one of which is movable, a distance between the first device and the second device. The first device includes a first reference signal source and a first transceiver configured to transmit two or more first carrier signals and receives two or more second carrier signals using an output of the first reference signal source. The second device includes a second reference signal source configured to operate independently from the first reference signal source and a second transceiver configured to transmit the second carrier signals and receives the first carrier signals using an output of the second reference signal source. The calculating section calculates the distance based on a phase detection result obtained by reception of the first and second carrier signals.

Methods and apparatus to detect proximity of objects to computing devices using near ultrasonic sound waves are disclosed. An example apparatus includes a frequency analyzer to determine power levels of noise in different frequency bands associated with sound waves sensed by a microphone of a computing device. The example apparatus further includes a signal generator to cause a speaker to produce a series of acoustic pulses. A central frequency of the pulses is defined based on the power levels of noise in the different frequency bands. The sound waves are sensed by the microphone to include the pulses and echoes of the pulses reflected off objects in a vicinity of the computing device. The example apparatus also includes an object detection analyzer to determine whether a first object is within an activation region associated with the computing device based on the pulses and the echoes sensed by the microphone.

Methods and apparatus to detect proximity of objects to computing devices using near ultrasonic sound waves are disclosed. An example apparatus includes a frequency analyzer to determine power levels of noise in different frequency bands associated with sound waves sensed by a microphone of a computing device. The example apparatus further includes a signal generator to cause a speaker to produce a series of acoustic pulses. A central frequency of the pulses is defined based on the power levels of noise in the different frequency bands. The sound waves are sensed by the microphone to include the pulses and echoes of the pulses reflected off objects in a vicinity of the computing device. The example apparatus also includes an object detection analyzer to determine whether a first object is within an activation region associated with the computing device based on the pulses and the echoes sensed by the microphone.

A method and apparatus to measure the fluid depth in a well or borehole is described. The approach reduces the effects of acoustic noise occurring near the top of the well or borehole that can interfere with the fluid depth measurement. A resonant acoustic structure between an acoustic transducer and the well or borehole provides efficient coupling of spectrally narrow acoustic signals into the well or borehole, as well as providing a bandpass acoustic filter on the returning signal, to improve the signal to noise ratio of the desired acoustic reflection.