Methods, apparatus, and systems for adaptive point cloud filtering for an autonomous vehicle are disclosed. At least one processor receives multiple LiDAR points from a LiDAR system. The multiple LiDAR points represent at least one object in an environment traveled by the vehicle. The at least one processor determines a Euclidean distance of each LiDAR point. The at least one processor compares the Euclidean distance of each LiDAR point with a respective sampled Euclidean distance from a standard normal distribution of Euclidean distances. Responsive to the Euclidean distance of a LiDAR point being less than the respective sampled Euclidean distance, the at least one processor removes the LiDAR point from the multiple LiDAR points to generate a point cloud. The at least one processor operates the vehicle based on the point cloud.

A system for detecting objects using ultrasonic waves and methods for making and using the same are provided. The object detection system uniquely encodes each of a plurality of ultrasonic waves and transmit each of the uniquely-encoded ultrasonic waves in a respective direction. The object detection system then receives any of the emitted uniquely-encoded ultrasonic waves that are reflected from an object. By decoding the reflected ultrasonic waves, the object detection system distinguishes among the uniquely-encoded ultrasonic waves and detect the existence and location of the object.

An underwater information display device, which transmits an ultrasonic wave, receives an echo reflected by an underwater target, and displays the echo, includes: a transmission signal generation part that forms a transmission signal sequence in which at least two temporally adjacent transmission signals are converted so as to be identifiable at the time of reception and have different intervals; a transmission part that emits a transmission signal as an ultrasonic wave into water; a reception part that receives an echo and outputs a reception signal; a storage part that stores multiple reception signals corresponding to temporally continuous transmission signals; an interpolation part to which reception signals stored in the storage part are supplied and which replaces a ghost component included in the reception signals with an echo of another temporally nearby transmission signal; and a display part that draws reception signals including a signal interpolated by the interpolation part.

A method for measuring a distance to a target in a multi-user environment by means of at least one sensor, comprising: irradiating the environment by means of a series of radiation pulses, wherein series of radiation pulses are emitted at a determined repetition rate and with a determined random delay; collecting pulses that are reflected or scattered from the environment to at least a detector connected to at least one chronometer; assigning a timestamp at every detected pulse on the detector; subtracting the added delay from every registered timestamp coming from the chronometer, the result corresponding to the time of arrival; determining the statistical distribution of said time of arrival; determining the distance to the target from said statistical distribution.

An ultrasonic detecting device may include a transmitter, a receiver, a motor, and processing circuitry. The transmitter may transmit a sequence including a first pulse wave and a second pulse wave separated by a time interval shorter than a time required for an ultrasonic wave to make a round trip underwater to a detection range. The receiver may convert reflection waves of the first and second pulse waves into echo signals. The motor may rotate the receiver. The processing circuitry may acquire, from the echo signals, a first echo signal and a second echo signal, generate first image data based on the first echo signals and second image data based on the second echo signals, and generate synthesized image data based on an angular position of the receiver when the first image data is generated, and an angular position of the receiver when the second image data is generated.

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 device comprises a processor coupled with an ultrasonic transducer which is configured to repeatedly emit ultrasonic pulses during transmit periods which are interspersed with listening windows. Each sequential pair of the transmit periods is separated by a single listening window of the listening windows. During a fixed portion of a listening window of the listening windows the ultrasonic transducer is configured to receive returned signals corresponding to an emitted ultrasonic pulse of the ultrasonic pulses which was transmitted during a transmit period of the transmit periods that immediately preceded the listening window. The processor randomizes an overall length of each listening window of the listening windows. The processor directs filtering of returned signals received during a plurality of the randomized listening windows to achieve filtered returned signals. The processor detects, using the filtered returned signals, a moving object in a field of view of the ultrasonic transducer.

A system for detecting objects using ultrasonic waves and methods for making and using the same are provided. The object detection system uniquely encodes each of a plurality of ultrasonic waves and transmit each of the uniquely-encoded ultrasonic waves in a respective direction. The object detection system then receives any of the emitted uniquely-encoded ultrasonic waves that are reflected from an object. By decoding the reflected ultrasonic waves, the object detection system distinguishes among the uniquely-encoded ultrasonic waves and detect the existence and location of the object.

In an emission process for remote sensing, pulse signals (630) are periodically produced in elementary time windows spaced one pulse period (T) apart, and waves corresponding to those signals are emitted towards remote objects, so as to enable to monitor waves transmitted by those objects upon receiving the emitted waves. The emission of those waves is periodically prevented, according to at least one inhibition period (3T, 5T) proportional to the pulse period and equal to at least three times that pulse period. Parameters are set, suited to producing measurement information on the objects from the wave monitoring, based on at least part of a frequency content of the transmitted waves to which the pulse and inhibition periods contribute. Applications to lidars, radars, active sonars and ultrasound monitoring.

An embodiment provides a method for measuring velocity and depth of fluid flow in a channel, including: transmitting, using a transmitter, directed energy comprising a single energy beam slant-wise toward a surface of a fluid in a fluid channel producing a plurality of reflections, wherein the transmitting comprises modulating a frequency associated with the single energy beam; detecting, at a receiver, received signals from the plurality of reflections; and determining, based upon differences between parameters of the transmitted single energy beam and parameters of the received signals, the velocity of the fluid and the depth of the fluid. Other embodiments are described and claimed.