A method of operating electro-acoustical transducers such as PMUTs involves applying to the transducer an excitation signal over an excitation interval, acquiring at the transducer a ring-down signal indicative of the ring-down behavior of the transducer after the end of the excitation interval, and calculating, as a function of said ring-down signal, a resonance frequency of the electro-acoustical transducer. A bias voltage of the electro-acoustical transducer can be controlled as a function of the resonance frequency. An acoustical signal received can be transduced into an electrical reception signal and a damping parameter of the electro-acoustical transducer can be calculated as a function of the ring-down signal so that a cross-correlation reference signal can be synthesized as a function of the resonance frequency and the damping ratio of the electro-acoustical transducer. Such a cross-correlation reference signal can be used for cross-correlation with the electrical reception signal to improve the reception quality.

An object detection apparatus detects an object in a vicinity of a moving body in a state of being mounted to the moving body. The object detection apparatus measures a reverberation frequency that is a frequency of a reverberation signal that is generated in a transceiver that externally transmits a transmission wave that is an ultrasonic wave and receives a reception wave that includes a reflected wave of the transmission wave from the object. The object detection apparatus detects a specific segment that is an occurrence segment in which occurrence of beat that is attributed to a plurality of reverberation frequency components is confirmed in the reverberation signal, or a non-occurrence segment in which the occurrence of beat does not significantly occur. The object detection apparatus sets a measurement segment in which the reverberation frequency is measured in the non-occurrence segment based on a detection result of the specific segment.

Ultrasonic ranging systems and methods that emit coded bursts and correlate transduced acoustical echoes of the bursts with a receive template characterizing a burst code to determine time-of-flight information use receive templates of time-variable length to improve short-range object detection. The template length is based on a time index measured from the start of the burst emission. The detection can account for a dead zone of transducer ringing following a burst. A time-variable gain that is also based on the time index can be applied to the correlated signal. The length and gain can be adjusted with reduced temporal frequency to reduce computation cost.

A system is provided for imaging an underwater environment. The system includes one or more arrays of transducer elements. Each array is operated at a fixed phase shift and varies in frequency so as to beamform multiple sonar return beams of a first range of angles and a second range of angles. The arrays can be oriented to cover the gap in sonar coverage for other arrays to create a continuous arc of sonar coverage. Accordingly, a 2D live sonar image can be formed. One or more of the multiple sonar return beams facing downwardly can be selected and used to form downward sonar images that anglers are used to, without requiring separate transducer elements. Fish arches formed using multiple sonar return beams can be positioned appropriately within a high resolution downward sonar image to form a desirable combined sonar image.

A system is provided for imaging an underwater environment. The system includes one or more arrays of transducer elements. Each array is operated at a fixed phase shift and varies in frequency so as to beamform multiple sonar return beams of a first range of angles and a second range of angles. The arrays can be oriented to cover the gap in sonar coverage for other arrays to create a continuous arc of sonar coverage. Accordingly, a 2D live sonar image can be formed. One or more of the multiple sonar return beams facing downwardly can be selected and used to form downward sonar images that anglers are used to, without requiring separate transducer elements. Fish arches formed using multiple sonar return beams can be positioned appropriately within a high resolution downward sonar image to form a desirable combined sonar image.

An ultrasonic type object detection apparatus sequentially detects a distance between an ultrasonic sensor and an object in a coverage of a transmission wave at a predetermined detection cycle based on a time taken for the ultrasonic sensor to transmit the transmission wave and then to receive a reflection wave. The apparatus includes: a storage storing the distance to the object; a vehicle information acquisition device acquiring vehicle information for calculating a movement distance; a detection distance predictor predicting a next detected distance to the object based on a past detection result and the vehicle information; and a short range determinator determining whether the object is present in a short range area in which the distance between the object and the ultrasonic sensor is equal to or shorter than a short range threshold.

An ultrasonic type object detection apparatus sequentially detects a distance between an ultrasonic sensor and an object in a coverage of a transmission wave at a predetermined detection cycle based on a time taken for the ultrasonic sensor to transmit the transmission wave and then to receive a reflection wave. The apparatus includes: a storage storing the distance to the object; a vehicle information acquisition device acquiring vehicle information for calculating a movement distance; a detection distance predictor predicting a next detected distance to the object based on a past detection result and the vehicle information; and a short range determinator determining whether the object is present in a short range area in which the distance between the object and the ultrasonic sensor is equal to or shorter than a short range threshold.

Provided are a sonar system and transducer assembly for producing a 3D image of an underwater environment. The sonar system may include a housing mountable to a watercraft having a transmit transducer that may transmit sonar pulses into the water. The system may include at least one sidescan transducer array in the housing that receives first and second sonar returns with first and second transducer elements and converts the first and second returns into first and second sonar return data. A sonar signal processor may then generate a 3D mesh data using the first and second sonar return data and at least a predetermined distance between the transducer elements. An associated method of using the sonar system is also provided.

A transmission/reception control device is configured to control transmission and reception in an ultrasonic sensor. The ultrasonic sensor includes an ultrasonic transducer. The ultrasonic transducer is configured to transmit a probe wave as an ultrasonic wave and receive a reception wave. The reception wave includes a reflected wave of the probe wave. The transmission/reception control device includes a transmission frequency setting unit, a reception signal processing unit, and an object detection unit. The transmission frequency setting unit sets a frequency of the probe wave to a transmission frequency different from a resonance frequency of the ultrasonic transducer. The reception signal processing unit processes a reception result of the reception wave based on the probe wave transmitted with the transmission frequency. The object detection unit detects the object based on a result of processing by the reception signal processing unit.

A sensor device, including a sensor having a sound transducer to emit sonic waves and convert received sonic waves to electrical signals. A sensor evaluation unit carries out surrounding-area monitoring during a normal operation of the sensor, by evaluating electrical signals of the sound transducer. During a monitoring mode of the sensor, a monitoring unit of the sensor device measures an impedance of the sound transducer for different excitation frequencies of excitation signals produced with a signal generator of the sensor device. The sensor device includes a first and a second signal path, which are each connected to the sound transducer and are connectable to the signal generator. To reset the sensor from normal operation to the monitoring mode, a first control unit of the sensor device is configured to decouple the signal generator from the first signal path and to connect it to the second signal path.