A constant false alarm rate (CFAR) device for a signal detection system is disclosed herein. The CFAR device includes a first signal selection unit and a second signal selection unit. The first signal selection unit receives a last signal of a lagging sorting array and signals of one or more lagging guard cells, selects any one of the last signal of the lagging sorting array and the signals of the one or more lagging guard cell as a test signal based on a received guard cell size, and outputs the test signal. The second signal selection unit receives the test signal and signals of one or more leading guard cells, selects any one of the test signal and the signals of the one or more leading guard cells based on the guard cell size, and transfers this selected signal to the leading sorting array.

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 obstacle detection apparatus for vehicles includes: a first ultrasonic sensor for detecting a distance to an obstacle; a second ultrasonic sensor at a position of the vehicle for receiving a reflection wave from the obstacle of an ultrasonic wave from the first ultrasonic wave; a notifier that gives a notification of detecting the obstacle present within a preset distance in one or more of predetermined notification areas including a first notification area for the first ultrasonic sensor, and a second notification area for the second ultrasonic sensor detects the obstacle for the vehicle; and a controller that controls contents to be notified by the notifier. Furthermore, the controller determines whether a first indirect wave distance and a second indirect wave distance are used to determine whether to give the notification of detecting the obstacle in the first notification area.

An object detection device equipped at a predetermined height includes a waveform obtaining portion obtaining a wave height value of a reflected wave, a reference value calculation portion calculating a wave height value of a wave reflected from a reference obstacle present at the predetermined height as reference value, a detection value calculation portion calculating a wave height value of a wave reflected from a detection object as detection value, a reference distance calculation portion calculating a reference distance between the reference obstacle and the distance measuring sensor, a detection distance calculation portion calculating a detection distance between the detection object and the distance measuring sensor, a correction portion correcting the reference value and the detection value, and a height calculation portion calculating a height of the detection object relative to the predetermined height according to a relative comparison result of the corrected reference value and the corrected detection value.

An object recognition device for vehicles, including a sensor, a filter device and an analysis device. Signals from an object are detectable by the sensor. The detected signals are filterable by the filter device and then feedable to the analysis device. The analysis device is configured to recognize the object by analyzing the filtered signals. The filter device includes an averaging unit, which averages the profile of the amplitudes of the detected signals, and a non-linear filter unit, which is provided based on a linear low-pass filter with a variable time constant and filters the detected signals. A value profile corresponding to the difference between the averaged amplitude profile and the filtered signals is feedable to the analysis device for analyzing and recognizing the object. The variable time constant is establishable based on the difference between the filtered signals and the detected signals and based on the averaged amplitude profile.

A method and system for inspecting casings in a wellbore to determine a mechanical or sealing quality of casing connections. Casing connections may become mechanically weak or start to leak after some period of use in harsh conditions. A radial array of ultrasound transducers images the casing in-situ to create an ultrasound image, which is analyzed to detect the casing connector then analyzed a sealing band of the connector. Machine learning and image processing methods may be used to analyze the images.

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.

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.