Abstract: A method for ultrasound imaging utilizes microbeamforming within a transducer probe in electrical communication with a base ultrasound system. The transducer elements are arranged in sub-arrays or subsets, and the transducer includes a cross-point/summation switch in communication with each sub-array, and the base ultrasound system. In the microbeamforming operation, the signals received at the receiving elements comprising a sub-array are summed to generate a composite sub-array signal for same sub-array, and a set of composite sub-array signals corresponding to a particular receive beamforming pattern is defined using a signal controlling the output of the cross-point switch.

Abstract: The present information comprises the stages of: applying frequency analysis to positional information on a platform, generating virtual positional information on the platform based on a frequency analysis result; extracting a signal based on the generated virtual positional information; and performing a synthetic aperture processing based on the extracted signal, and in this manner, even if the positional information lacking in precision and inaccurate is used, the shake compensation of the platform in the synthetic aperture processing system can be effectively performed.

Abstract: A target tracking arrangement predicts the state of a target. The predictor may be a Kalman filter. In the presence of a target which is maneuvering, the prediction may be in error. A maneuver detector is coupled to receive residuals representing the difference between the predictions and the target state. The maneuver detector is matched to the predictor or Kalman filter to thereby tend to reduce the undesirable effects of system noise. The matching may be of the frequency response.

Abstract: An area is established by positioning a string of boundary objects that are reflective to a range of ultrasonic frequencies. Tracking objects may be placed inside the area which also are reflective to the range of ultrasonic frequencies. An array of transducers insonify the area and the reflected signals are received by each transducer, digitized and stored as digital data. The digital data is read out in time reverse order and time reversal signals are generated that are coupled to each corresponding transducer. The time reversed signals focus energy on the reflective sources. The reflected signals resulting from the time reversed signals are analyzed to generate a reference signature indicating relative locations of boundary and tracking objects. The time reversed signals are sent intervals to generate new signatures which are compared to the reference signature to determine if tracking objects have been moved outside the area.

Abstract: In the present invention a refiner (108) of a mechanical pulping line is supplied with a controllable acoustic source (14), arranged for emitting acoustic signals into the pulp fluid. The controllable acoustic signal is allowed to interact with the fibres in the pulp, and the acoustic (pressure) signals resulting from such an interaction is measured. At least one spectral component is measured. The measured spectral component is used to predict properties, content and/or size of the fibres. These properties may then be used to control the refiner (108) process. The used acoustic signal has preferably a wavelength that is large compared with a typical site of the particles.

Abstract: One preferred embodiment of the present invention provides a system and method for suppressing motion artifacts introduced by movement of a radar detection system. Briefly described, in architecture, one embodiment of the system, among others, can be implemented as follows. The system includes a Doppler radar module configured to transmit a microwave signal directed towards an object and receive the reflected microwave signals from the object and a living subject positioned behind the object. Also, the system includes a reference module configured to transmit a reference signal towards the object and receive the reflected reference signal from the object. By comparing the two reflected signals from the Doppler radar module and the reference device, a signal processor suppresses motion artifacts generated by movement of the Doppler radar module to identify the presence of the living subject behind the object. Other systems and methods are also provided.

Abstract: An ultrasonic distance-measuring method and device using variable-length transmitted pulses. For this purpose, the length of each of the transmitted pulses is adjusted such that it is approximately proportional to the measured time interval of a transmitted pulse between the transmitter and an obstruction or object. The method can be used in particular for measuring the distance between the rear panel of a utility vehicle and a loading platform.

Abstract: A range finding audio system automatically modifies the audio output of an audio source based on the distance of a listener from the speakers. A speaker in an audio system may include a range device coupled with a controller. The range device may utilize infrared, laser, or acoustic technology to determine the distance between the speaker and the listener. The controller may transfer distance information to an audio interface of a processor unit. The audio interface may include a positioning routine to modify the audio output according to the distance from the speaker to the listener. Alternatively, the controller may perform the functions ascribed to the positioning routine making the necessary modifications to the audio output based on the distance information.

Abstract: The present invention relates to a system for using signals scattered by targets to determine position and velocity for each of the targets and comprises a set of transmitters and receivers of electromagnetic or acoustic signals, said transmitters and receivers dispersed to known points. Each pair of transmitter and receiver, monostatic or bistatic, is named a measuring facility. The ranges of the transmitters are chosen so that a target at an arbitrary point within the position space can be measured via scattering in the target by at least four measuring facilities. For each measuring facility, target detection occurs with constant false alarm rate in the form of probabilities over resolution cells with regards to range and Doppler velocity and conceivable targets are placed in a 2-dimensional linear space belonging to the measuring facility.

Abstract: A vehicle object detection system is disclosed that audibly conveys to the vehicle operator the direction of the detected object relative to the vehicle through the vehicle's audio system. The system includes a sensor array, a processor, and a speaker arrangement. The sensor array detects an object remote from the vehicle and generates a signal when an object has been detected. The processor receives and processes the sensor array signal. Then, the processor transmits the processed signal to the speaker arrangement. The speaker arrangement audibly conveys the processed signal over multiple audio channels. The method of detecting an object remote from the vehicle is also disclosed.

Abstract: A method and apparatus for reducing sonar measurement error in noisy environment, by monitoring environmental noise spectrum over the range of operable sonar frequencies, and automatically changing the system sonar transmission frequency and its dependent components in order to avoid the detected interference frequencies. A wide band transceiver and a digital signal processor (DSP) can be used as a Frequency Server, and to monitor the environmental noise spectrum continuously through the use of Fast Fourier Transform (FFT) algorithm to produce noise frequency database for the Frequency Server. Each transmission cycle, the DSP dynamically getting frequency from the Frequency Server were noise is below a certain level for sonar transmission and adjust its dependent components accordingly. Thus, continuously maintains reliable measurements even in the presence of sporadic interference.

Abstract: The invention relates to the detection of the position of an object which can be moved along an acoustic-signal conductor of ferromagnetic material, in which an acoustic signal is incoupled in a clocked manner into the acoustic-signal conductor by means of a signal input coupler connected to a signal transmitter, extracted by means of a signal output coupler and the extracted signal is evaluated by an evaluating circuit for generating a signal representative of the instantaneous position of the object, wherein an opposite magnetic field for the magnetic field generated by the acoustic signal is incoupled in each case after the incouplion of the acoustic signal.

Abstract: A method and a device for detecting if an object is in proximity to the device, wherein sound (audio) transducers already found in the device are used to realize the proximity detection function, along with digital signal processing or equivalent means. The audio transducers are preferably those designed for use with human hearing and speaking capabilities in the range of about 20 Hz to about 20 kHz, and need not be specially designed transducers. The method includes steps of generating a measurement signal; driving an output acoustic transducer of the device with the measurement signal; monitoring an input acoustic transducer of the device to detect the measurement signal; and determining that an object is in proximity to the device based on a detected alteration of the measurement signal. The device may comprise a mobile telephone, such as a cellular telephone, or a personal communicator.

Abstract: An apparatus for detecting a fluid level is disclosed, which includes a coaxial sensor having a pair of conducting tubes positioned with respect to each other in spaced coaxial arrangement, a coaxial transmission line connected to the sensor, a means for injecting a standing wave into the coaxial sensor, a summer for summing the injected wave and a reflected wave connected to the sensor, a means for adjusting the frequency of the injected wave in response to the voltage and phase of the summed signal, and a processor for processing and displaying the frequency as a representation of the level of the fluid. A method for detecting the fluid level is also disclosed.

Abstract: A method for improving ROP and reducing hazards in drilling subterranean wells by using an acoustical system 15 to look ahead of the drill bit 14, detects and analyzes geologic features ahead of the bit 14 which may be qualified as drilling hazards 17. Detection of such hazards 17 may facilitate use of more aggressively penetrating bits 14 such as PDC bits as opposed to roller cone bits. In addition, other drilling parameters may be adjusted to improve ROP due to the ability to timely respond to identified hazards 17 before they may be detrimentally encountered by the bit 14. The acoustic system 15 may look ahead of the bit 14 by at least 100 meters, using propagated acoustic waves 19 to locate changes in acoustic impedance which may represent drilling hazards 17. In addition, bulk resistivity ahead of the bit 14 may also be measured and used to locate drilling hazards 17.

Abstract: A device for measuring a fill level of a liquid includes an ultrasonic sensor with two sensor elements. One of the sensor elements determines the echo time of an ultrasonic wave to a float which follows the liquid level. The other of the sensor elements determines the echo time of the ultrasonic wave up to a measuring reflector arranged at a known distance from the other of the sensor elements. An evaluation unit compares the echo times and determines the fill level of the liquid from the ratio of echo times and from the known distance to the measuring reflector.

Abstract: A radar device for use in backing up a vehicle is disclosed herein. A plurality of wave sensors is installed on a rear portion of a vehicle for detecting an obstacle therebehind. A master controller has a plurality of transceiver circuits and a microprocessor connected to the plurality of transceiver circuits. Each transceiver circuit corresponds to one of the plurality of wave sensors. The microprocessor activates the plurality of transceiver circuits to drive the plurality of wave sensors for transmitting and receiving ultrasound wave signals thereby determining the location of the obstacle. A location display device is connected to the master controller for receiving and decoding data related to the location of the obstacle thereby indicating the direction of the obstacle and displaying in numerical form the distance between the obstacle and the vehicle.

Abstract: An apparatus for protecting a keyboard and includes a sound transformer placed in the keyboard and a sound receiver placed outside the keyboard to receive a signal radiated from the sound transformer. The signal is then analyzed to determine if the power of the radiated signal has dropped below a threshold value, indicating potential tampering of the keyboard.

Abstract: A vehicle alarm comprises of a control unit (2) coupled to a message center (22) and an ultrasonic movement sensor (20). The ultrasonic movement sensor (20) is automatically activated when the vehicle ignition is switched off. If movement is not detected in the time period between switching the ignition off and the driver's door being closed, then the ultrasonic movement sensor (20) is deemed to have failed. A count of such failures is kept and when a predetermined number of such failures has occurred, a warning message is displayed on the message center (22). If movement is detected in the time period, the count is reset to zero. In this way, the alarm can automatically determine whether or not the ultrasonic movement sensor (20) is functioning correctly.

Abstract: A system and a method for directing a torpedo toward a submerged or surface arget by transmitting steering information to the torpedo via sonic pulses. A suitable underwater surveillance system, such as the Correlation Sonobuoy System, provides an observer with the necessary information regarding the relative bearings of both the torpedo and the target. Using sonic signals generated by one of a variety of suitable sources, the torpedo is steered into the general vicinity of the target while the positions of both torpedo and target are tracked on the underwater surveillance system display. Once directed to the general area of the target by this technique, the torpedo's internal target homing system is activated either automatically or by additional sonic pulses to complete the attack on the target.

Abstract: A method and device for ultrasonic ranging. As in prior art devices, ultrasound pulses are transmitted by the device towards a target, and echo pulses from the target are received. The timing of the maximum of the amplitude envelope of the echo pulses is picked and used as a measure of the return time of these pulses. This maximum envelope time is relatively independent of the speed of sound between the device and the target. Preferably, the duration of the echo pulses is less than the response time of the receiving circuit, to enable an accurate pick of the amplitude envelope maximum.

Abstract: A dispensing system includes a robot that controls the positional location of a dispenser that dispenses a bead of material, such an adhesive, onto a substrate and wherein a sensor monitors the geometric configuration of the material dispensed. The dispensing system also includes a control circuit which receives information from the sensor so as to monitor geometric characteristics such as height, width and cross sectional area in such a manner that statistical process data can be gathered and also to provide alarm indications whenever the height or width of the bead do not comply with predetermined characteristics. The control circuit also provides a closed loop feedback system so that the supply of material and the nozzle can be controlled in such a manner to modify the flow of bead material whenever a discrepancy or error is detected by the control circuit.

Abstract: A novel system and method for treating an object with sonic waveforms. A traveling broad-band sonic waveform containing a broad-band of sonic frequencies is radiated at the object. A traveling reflected sonic waveform containing sonic frequencies reflected by the object is received in response to the traveling broad-band sonic waveform. A traveling transmitted sonic waveform containing sonic frequencies transmitted through the object is also received in response to the traveling broad-band sonic waveform. In a resonance mode, the frequency spectra of the broad-band and reflected sonic waveforms is analyzed so as to select one or more sonic frequencies that cause the object to resonate. An electrical resonance treatment sonic waveform containing the sonic frequencies that cause the object to resonate is then radiated at the object so as to treat the object.

Abstract: A non-invasive, synthesizing array of "N" reciprocal transducers is driven by "N" linearly independent inputs for three-dimensional sound field specification at "N" locations either within, or on, an isotropic or anisotropic acoustic/elastodynamic medium. Towards these ends, the impulse response, or Dyadic Green's Function Matrix, characteristic of the medium is determined, and the desired sound field response at "N" locations either within, or on, the surface of the medium is specified. This results in a system of "N" equations, which can be solved to obtain the "N" linearly independent inputs required to create the "N" desired, three-dimensional sound field responses. This permits precise focusing and spatial manipulation of sound intensity, as well as amplitude control within a specific volume or region of convergence within, or on, the medium.

Abstract: An acoustic ranging and detection system comprises an acoustic transmitter for producing an acoustic ranging signal and first and second acoustic receivers positioned on either side of the acoustic transmitter. A support mounts the acoustic transmitter and both acoustic receivers for concurrent rotation about a central axis passing through the acoustic transmitter. A first motor is connected to the first acoustic receiver and is adapted to impart independent rotative movement thereto. A second motor is connected to the second acoustic receiver and is adapted to impart independent rotative movement thereto. A control system is responsive to echo signals from a target that are received by the first and second acoustic receivers to rotate the support to point the transmitter at the target and further operates the first and second motors to cause the respective acoustic receivers to be repositioned so as to manifest receiving beam patterns which exhibit central axes that intersect in the region of the target.

Abstract: A method and apparatus is provided to detect the position of an object, such as a container, within a multidimensional target space above which is a dispensing spigot to dispense water, ice, or other beverage. The dispenser control is also applicable to other applications, for example, dispensing soap in response to the detecting of human hands. The system has a transceiver emitting pulses of ultrasonic waves, a portion of which are reflected by the object in the target space and detected by the transceiver, and a processing circuit for determining the relative strength of the reflected signals and the time it takes an ultrasonic wave to be emitted, reflected, and received by a transceiver. The received signal is checked to determine if the amplitude of the reflected ultrasonic wave is consistent with an object occupying the target space. A timer circuit creates a timing window which further defines the target space.

Abstract: When operating adjacent ultrasonic proximity switches, faulty output states can occur due to mutual interference (e.g., the incorrect allocation of echo signals). To solve this problem, it is known to adhere to standard mounting specifications as well as to apply parallel or serial synchronization. Ultrasonic proximity switches with an enabling output and a microprocessor are improved by inserting a circuit arrangement between these two elements, which, based on synchronizing pulses, produces a change in potential from high to low at the enabling output. By connecting the enabling outputs of several proximity switches constructed in this manner and operated adjacent to one another through a shared line, an improved operation with parallel and serial synchronization is possible without external control (i.e., automatically). The low potential state produced by an ultrasonic proximity switch at its enabling output is supplied via the line to the remaining connected ultrasonic proximity switches.

Abstract: A system for producing reliable navigation data for a mobile vehicle, such as a robot, combines multiple range samples to increase the "confidence" of the algorithm in the existence of an obstacle. At higher vehicle speed, it is crucial to sample each sensor quickly and repeatedly to gather multiple samples in time to avoid a collision. Erroneous data is rejected by delaying the issuance of an ultrasonic energy pulse by a predetermined wait-period, which may be different during alternate ultrasonic firing cycles. Consecutive readings are compared, and the corresponding data is rejected if the readings differ by more than a predetermined amount. The rejection rate for the data is monitored and the operating speed of the navigation system is reduced if the data rejection rate is increased. This is useful to distinguish and eliminate noise from the data which truly represents the existence of an article in the field of operation of the vehicle.

Abstract: An ultrasonic non-contact motion monitoring system, useful for monitoring motional activities and such activities as respiration rate and heart beat rate. Using dual ultrasonic transducers, coherent sound waves are directed toward a moving subject. The phase frequency relationship of the reflected waves are compared to the transmitted sound waves in-phase and in phase-quadrature. The derived information, containing movement activity, is either displayed locally or sent to remote station(s) for display, processing and storage.

Abstract: A device for selectively detecting in real time a moving object progressing on a path in a multidimensional space, the device comprising first means determining an efficiency, corresponding to the ratio of net displacement to total distance travelled, and for selecting moving objects on the basis of this ratio. To account for objects making half turns in an otherwise efficient path, from the data constituted by the measurements of displacements of the moving object, an average of the efficiency of motion is used. The device is useful, for example, for real-time image sequence processing in conjunction with the tracking of moving objects.

Abstract: The transmitting pulse required to operate an ultrasonic proximity switch is usually generated externally in separate evaluation electronics. This requires additional circuitry, either analog or digital circuits, or a microprocessor and associated software. In the case of ultrasonic proximity switches, which have an integrated circuit with transmitting oscillator, the generation of the transmitting pulse is performed by additional means provided on the integrated circuit for generating a transmitting clock pulse. By means of a control signal, it is possible to select between the operation with this transmitting clock pulse and a transmitting clock pulse supplied externally by the evaluation electronics.

Abstract: An ultrasonic level detector includes a transducer for generating and receiving bursts of sonic energy at a surface to locate the position of the surface. In response to receiving a burst of energy reflected from the surface, the transducer generates an electrical signal, which is then supplied to a variable gain amplifier. After amplification, the electrical signal is supplied to a comparator and a peak detector. The comparator generates a timing signal upon the electrical signal exceeding a threshold. A window generator circuit generates a receive window that controls whether the electrical signal is supplied to the comparator and the magnitude of the threshold on the comparator. The peak detector determines the maximum amplitude of the electrical signal, which may be used to vary the amplifier gain and the number of pulses included in an excitation signal which drives the transducer. Upon receipt of the timing signal, a microprocessor determines the distance between the transducer and the detected surface.

Abstract: Articles, moving along a delivery path, are counted by directing a stream of pressurized air toward one major surface of the passing articles, the direction of the air stream being transverse to the direction of travel. Sensors arranged about the air stream detect the acoustic signal which varies with changes in the profile of the passing articles, exemplified by signatures. The detected acoustic signal is divided into a plurality of frequency ranges which, in one preferred emboidment, are averaged to reduce the effect of noise which may be present in only limited ones of the frequency bands. The averaged signals are then compared against thresholds to determine the instantaneous state of the articles, exemplified by a signature stream, to generate count signals.

Abstract: A milking cup is moved into position surrounding a cow's teat by power operated members controlled by an electrical circuit including a pair of spaced ultrasonic detectors for locating the teat. Each detector includes a transmitter and a receiver. The ultrasonic fields produced by the transmitters intersect one another at a position spaced from the transmitters. Conical reflecting surfaces are disposed adjacent the transmitters and receivers to reflect ultrasonic waves to obtain a detection field of predetermined dimensions and to determine the area within which the ultrasonic waves are reflected back to the receivers. The generatrix of the conical reflecting surfaces may be slightly concave or convex.

Abstract: A borehole televiewer employs a transducer energized by repetitive voltage pulses for generating pulses of acoustic energy for transmission to the walls of a borehole and for detecting direct reflections of acoustic energy from the borehole walls. A detector converts the acoustic energy reflections into reflection signals. Those reflection signals are applied along with a reference signal representing a desired constant level for the peak amplitude of the reflection signals to an error amplifier. The output of the error amplifier controls the voltage pulses utilized to energize the transducer so as to maintain a constant level of peak amplitude for the reflection signals produced from the detected acoustic energy direction reflections from the borehole wall.

Abstract: A sonar system is disclosed that includes contiguously angularly disposed d oppositely rotated transmitting and receiving transducers for broadcasting an acoustic signal and for receiving target echoes thereof, respectively, at different angles from within overlapping zones thereof within an aqueous medium. A gated transmitter is employed to timely energize said transmitting transducer, and a gated target seeking receiver is employed to process the output signal of said receiving transducer. A cathode ray tube readout displays target signals from said receiver. A light sensitive probe produces an electrical output signal in response to a target signal displayed on said cathode ray tube which is used for gating the aforesaid transmitter and receiver in such manner as to accentuate the displayed target signal being probed at any given instant.

Abstract: The invention comprises an arrangement for controlling a machine by means of the body movement of the operator. It is used for controlling a sewing machine intended for a handicapped person or for an operator not using the foot control. A pulse (18) consisting of a number of periods of 40 kHz sound waves are emitted from a loud-speaker (15). The sound waves are reflected by the head of the operator and a digital circuit measures the time takes the sound pulse to return to the receiver (16). The distance measured to the head of the operator is then used to proportionally control the speed of the machines motor.

Abstract: A distance detecting apparatus has a transmitter for transmitting a cyclic output signal. The transmitter is digitally controlled to adjust the frequency of the output signal in relatively small increments through a band of frequencies. A receiver receives a cyclic reflected signal and has an adjustable center frequency of response. There is a device for adjusting the center frequency of response to correspond to the frequency of the output signal. The apparatus may have digital control for controlling the power level of the output signal. There may be a digital control for the gain of the receiver. The apparatus may also include a transducer for converting electrical signals to ultrasonic signals and include controls for adjusting the frequency of the output signal according to requirements of the transducer.

Abstract: An apparatus for automatically sensing televiewing distance to determine whether or not a televiewer is standing within a predetermined potentially harmful distance in front of a television set by making use of the elapsed time difference between an ultrasonic pulse generated and emitted from a transmitter located on the television set and which is then reflected from a televiewer located in front of the television set. The reflected pulse is then received by an ultrasonic wave receiver also located on the television set and in the event that the televiewer stands within the predetermined distance for a time longer than is required, for example, to make a manual adjustment to the television set, a signal is generated which deactivates the video portion of the television set until such time that the televiewer moves to a safe distance away from the set beyond the predetermined potentially harmful distance at which time the video portion is again reactivated.

Abstract: A control method wherein a TV receiver, under the programmed control of a microcomputer, prevents infrared signals from a remote control transmitter and a watch-distance-limit-device transmitter from interferring with each other while using only one time-shared receiver for both functions.

Abstract: A viewing distance sensor for television receiver which cannot influence the remote infra-red control function over other electronic equipment positioned in the vicinity of a television receiver and also cannot be influenced by the infra-red signals transmitted from other electronic equipment. An infra-red signal is transmitted from the infra-red signal transmitter where a viewer is positioned within a viewable distance from the front of television receiver, whereby false operation caused by the infra-red signal from other equipment can be avoided. Also, an inhibiting control signal is applied to the screen controller of a television set where infra-red signals transmitted from other electronic equipments are received by the infra-red receiver in the television receiver, whereby false operation of the viewing distance sensor can be further avoided.

Abstract: An ultrasonic sensor system particularly for automatic door openers of a swinging door type, in addition to sensors (14) for people approaching a door for controlling opening and closing purposes, has at least one microprocessor controlled ultrasonic beam transducer (40, 41) for projecting an expanded unidirectional ultrasonic beam in a selected detection zone in the path of the swinging door and an ultrasonic detector for converting reflected ultrasonic beam energy into an analog electrical signal which constitute an acoustical image of objects in and bounding the selected detection zone. This acoustical image is stored or, a number characterized thereof is stored and this acoustic image is then compared with a later acoustical image of an object in the selected detection zone and then the comparison is used to signal a lack of correlation between the first and second acoustical images to produce a signal preventing operation of the door opening.

Abstract: A method of and apparatus for counting objects present within a predetermined area, by detecting acceleration and deceleration of the objects employ at least one Doppler radar to sense the movements of the objects by monitoring the Doppler frequencies of signals reflected from the objects, amplifying the Doppler signal reflected from each of the objects to provide an amplified signal, effecting an automatic gain control of the amplified signal to provide a signal of substantially constant strength independent of the distance and size of the respective object, detecting a frequency variation of the constant strength signal as an indication of change in the speed of movement of a respective one of the objects, determining whether the constant strength signal represents an acceleration or deceleration of the respective object, and correspondingly modifying a count representing the number of the objects in the predetermined area.

Abstract: The depth of water ahead of a vessel is detected by sonar means carried aboard a drone stationed by radio control ahead of the vessel. Detected depth information is transmitted from the drone to the vessel where it is displayed for use by the vessel pilot in navigating shallow waters.

Abstract: Apparatus for sensing distances in air by transmitting an ultrasonic pulse and measuring the time for return of an echo from a target object is characterized by ability to measure distances to multiple target objects. Preferably the apparatus defaults by displaying the distance to the nearest target but is provided with a push button which when pressed once causes display of the distance to the next target further away, when pressed again causes display of distance to a target after that and so forth. This novel function may be accomplished by discrete logic components or using a microprocessor.

Abstract: A method of and apparatus for carrying out machine vision of an object for obtaining object data therefrom in which the object is illuminated by frequency swept ultrasonic stress wave energy from a transmitting and receiving transducer array, or by light energy from a source, reflected signals are received respectively by the array and an optical-electronic camera, respective images in terms of the data contained in these received signals are fed to a processor in which the data is analysed to make use of the best data derived from both sources of illumination and the resulting data compared with reference data to provide stimuli controlling a reject device and/or positional adjustment devices directing the array and/or the camera.

Abstract: A method of and an arrangement for measuring the velocity and/or length of moving objects using the Doppler principle. Measurement of the velocity of objects over a wide range imposes stringent requirements on the bandwidth of the electronic apparatus which process the Doppler shift. The velocity and/or length are measured accurately using simple, narrow-band electronic processing circuits by imparting a pre-shift to the frequency of the electromagnetic wave directed towards the object to be measured. This pre-shift is opposite to the Doppler shift generated by the movement of the object and is realized by imaging a light beam originating from a laser onto the object via a rotating phase grating. The rate of rotation of the phase grating is controlled so that the total Doppler shift measured is always constant.

Abstract: An ultrasonic distance sensing method and apparatus are disclosed in which a transducer periodically transmits a pair of bursts of acoustic energy along an acoustic path toward a target object, an echo of the first acoustic burst in each burst pair is used to establish a peak reference level, and an echo of the second burst in each pair is used to determine distance to the target object only if its level exceeds a predetermined fraction of the peak reference level.

Abstract: A bistatic sonar employing LMS adaptive spatial prediction is used to process against surface reverberation from the convergence zone (CZ). Hydrophones spatially separated from the primary array are used as references. The critical behavior exploited by the invention is that since the reverberation may be viewed as an extended source for the reverberation, the correlation drops off with separation between the reference and primary sensors, while it stays a constant for the plane wave target return. The reverberation is non-stationary, functionally dependent on the signal (even though the back scatter is statistically uncorrelated with the signal), and spatially extended over the sector of the CZ annulus cut out by the transmitter azimuth beamwidth. The detection of the target is based on the sudden appearance of one strong target point source within a densely packed region of weak point sources that have been constantly present and whose sum is much larger than the target.

Abstract: From a first aspect this invention provides a missing pulse detector for determining the true termination time of a sequence of pulses in a signal of an assumed predetermined length having a rising edge and a trailing edge which may include pulses which do not reach a predetermined threshold, the detector including a counter connected to count pulses exceeding said threshold, up to a predetermined number, an oscillator for producing pulses at twice the frequency of the pulses in the signal and an enabling circuit for allowing pulses from the oscillator to pass to the counter only after the termination of a sequence of threshold-exceeding pulses from the signal.