Abstract: The invention is a portable human height measuring device. The device consists of an ultrasonic distance sensor, a controller and several output units. The ultrasonic distance sensor measures a person's height. The control unit converts the electronic signals from the ultrasonic sensor to proper measuring standards. The measurement output units displays, announces, or/and prints the measurement. The device is integrated onto a baseball like cap. The ultrasonic sensor is mounted on the sun visor of the cap. The control and output units are mounted on the crown of the cap. A switch is mounted on the top of the inner cap. When the head of the person wearing the cap touches the switch, it triggers the ultrasonic sensor to start measuring. The person's height is then converted to the proper measuring unit, and communicated to the person via output units.

Abstract: A spatial awareness device comprising at least one receiver adapted to receive a selected form of radiation and operatively coupled thereto at least one tactile responsive element. The received radiation can be converted into a tactile map spanning at least in part a limb of an individual such as a hand or foot.

Abstract: An ultrasonic path guidance system and method for the visually impaired uses an array of ultrasound transmitters that are directional and aimed at distinct locations forward of the user. The transmitters are positioned on the torso of the individual user and one or more receivers detect echoes from obstacles upon which the transmitted ultrasound sound impinges. Audible tone is generated each time an echo is received. The tone's frequency is dependent on which transmitter transmitted the original ultrasound pulse that resulted in the detected echo. This gives an easy to understand indication of the location of detected obstacles. The elapsed time from emission of an ultrasound pulse to reception of its echo is used to arrive at the distance to the obstacle.

Abstract: A ground penetrating radar system including a processor for generating audible output signals having discrete frequency components representative of the depth of buried targets. The amplitude of the audible frequency components is representative of the size or mass of the target.

Abstract: The invention relates to a device to aid the orientation of blind and partially sighted people. The device comprises a long cane and an additional device comprising a laser measuring system. By transmitting and receiving laser beams the laser measuring system detects objects in a planar detection area of a detection plane containing the long cane. Indicating means indicates the presence and the absence of objects in this planar detection area by a first and by a second information, respectively, for example by the presence of a determined signal and by the absence of a determined signal. This allows to detect objects above the long cane.

Abstract: Ultrasound is used to determine, by echo ranging, the distance of objects in front of a user for allowing a visually impaired pedestrian to walk safely. A double circuit allows two simultaneous measurements. Distances measured are converted into human paces or steps. Then each ear of the human receives measurement information. The user can calibrate the apparatus for his or her own stride.

Abstract: A spoken word-producing detector identifies objects by comparing signatures of detected objects with stored signatures of known objects. When the signatures compare, the detector produces stored word sounds associated with the detected object identifications. An annunciator produces the words from pre-digitized human voice sounds. A screen displays the words.

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: The invention relates to device serving as an orientation aid for blind and visually disabled, comprising at least one contactless distance measurement system (1,2) which provides correcting variables depending on the distance between the device and an object detected by the distance measurement system (1,2). At least one indicating device is also provided, which is impinged upon by the correcting variable of the distance measurement system (1,2) and which supplies an indication depending on the correcting variable. The indicating device comprises at least one tactile indicator (3) which is continuously or quasi-continuously displaced along a tactile path as monotone function of the distance measured by the distance measurement system (1,2). The tactile indicator can, for instance, comprise an adjustable element (3). The user can thus feel the distance measured by touching the position of the displaceable element (3).

Abstract: An ultrasonic sensor to monitor motion and position to provide interactive feedback to an individual during exercise or play. The sensor can measure distance and speed, count repetitions and calculate cumulative energy spent in an activity. The sensor has a display and an audio generator to provide interactive feedback to the individual. The sensor has a card port which can accept small program chips chosen by the user to add functions, enhancements or applications.

Abstract: An audible traffic signal adding apparatus for visually impaired persons includes two speakers and a control section. The two speakers are disposed at two ends of a crosswalk. The control section navigates a visually impaired person crossing the crosswalk by alternately outputting different sounds as in "back and forth call" operation from the two speakers disposed at the two ends of the crosswalk to the visually impaired person for a period during which crossing is permitted.

Abstract: A personal direction finding apparatus for determining the direction to be followed in order to reach a predetermined spot which includes a headset provided with two earphones and a circuit for generating a track error signal. The circuit includes a compass supported on the headset for outputting a heading signal corresponding to the heading of the direction of travel, a receiver for a position location and navigation system outputting a signal for the heading to be followed via one output, and a track error computing circuit.

Abstract: A personal object or obstacle detector apparatus with enhanced stereo imaging capability includes a sonar system having dual receivers with field lobes positioned based on psychoacoustic considerations such as interaural intensity difference (IID) and interaural time difference (ITD). Receiver field pattern shapes and directions are selected to match the natural IID and ITD associated with human hearing. In one embodiment, dual receivers are used with a common transmitter while another embodiment utilizes two transmitter/receiver pairs with the transmitter and receiver collocated.

Abstract: An aiming point system and technique for defining the aiming point of a d collection receiver used by an operator. A data receiver is directed to the aiming point for collecting and amplifying sub-audio signals emitted from rotary aircraft. The sub-audio signals are converted to audible signals by a voltage to frequency converter. The aiming point is readjusted manually or automatically in response to the sub-audible strength of the audible signal to obtain at least a substantial proportion of the target signature of the rotary type aircraft. The data collection receiver may include binoculars with a silicon photo detector and pre-amp within one of the binocular eyepieces.

Abstract: A collision alert system employs binaural acoustic effects to direct the attention of a person in a desired direction. In one embodiment, the angular location of a possible collision risk is detected to energize one of a plurality of acoustic generators spaced angularly apart about the cockpit of an aircraft. The Pilot utilizes normal delay and acoustic modification of high frequencies to determine the direction to look for the target. In another embodiment, the pilot wears headphones which inhibit normal binaural direction location. The delay and acoustic modification are simulated before being fed to left and right headphones. In a wired system, the headphone signals are produced off the headphones. The head angular position of the pilot is compensated so that, as the pilot's head is turned toward the simulated target position, the delay and acoustic modification are adjusted to compensate for the actual head position.

Abstract: The invention relates to an orientation aid for visually impaired and particularly blind persons. In this connection, at least one signal device (5, 6) for the indicating of a change in the direction of walking is associated with a memory (7) for the storing of a selectable direction of walking.

Abstract: A personal object or obstacle detector apparatus comprises a continuous transmission frequency modulation (CTFM) ranging system and an audio output device. The CTFM ranging system transmits a frequency-swept pressure wave, receives a reflected frequency-swept pressure wave from at least one object, and forms an audio signal based upon a frequency difference between the frequency-swept pressure wave and the reflected frequency-swept pressure wave the audio signal having an amplitude dependent upon size of the object. The audio output device produces an acoustic pressure wave in dependence upon the audio signal. In a preferred embodiment, the acoustic pressure wave contains separate tones for each of the objects detected, wherein each tone has a pitch dependent upon the distance from the CTFM ranging system to the corresponding object. Another embodiment utilizes a pair of CTFM ranging systems to produce a stereo auditory map of objects and obstacles.

Abstract: A user-driven, active guidance system for guiding visually impaired users through obstacle filled routes of travel. The system includes an obstacle detection system, having an array of ultrasonic sensors, which detects the distance to and location of obstacles and a controller for receiving obstacle data and determining an optimal path around the obstacle so as to return the user back to the original path of travel without losing orientation or direction. The system provides active guidance by exerting physical force upon the user to intuitively direct the user around the obstacle. The system is driven by the user's motion and comprises a cane, as well as the my of ultrasonic sensors and controller supported on a pair of guide wheels.

Abstract: An apparatus for converting the difference frequency between the transmit lse of a sonar and the return or receive signal from a target to a video representation complementing the audio output of the sonar representing the difference frequency. The audio and complementing video signal indicate the presence of the target and its range. The invention converts the audio signal to a frequency spectrogram by means of digital signal processing including a FFT algorithm. The amplitudes of the frequency components of the audio signal are plotted on the video display of the invention. They are color-coded to indicate the amplitude of the audio signal. The frequency of the audio signal is related to the range of an object detected by the sonar. The invention is mobile and easily managed by a diver.

Abstract: This invention relates to an optical disc apparatus and the evaluating method of the optical disc apparatus, which emits the light beam to the disc typed recording medium to sequentially form pits and records the desired data, and the asymmetry, etc. can be detected rapidly and surely. The peak value and the bottom value of the reproduced signal are sequentially held to detect the minimum value and the maximum value of the held result, and then the recording system, the characteristics of the disc typed recording medium, or the reproducing system can be evaluated based on the detected result.

Abstract: A small "flashlight" size pointing device for use as a sonar obstacle avoidance system for the blind. The apparatus comprises a bundle of small diameter tubes mounted in front of and perpendicular to the plane of a transducer. The transducer transmits sonic or ultrasonic pulses down the tubes which then spread out as a wave. Reflected waves, returning from obstacles are only detected by the transducer if they originate in a certain spatial beam area. This spatial beam area is controlled by the length and diameter of the tubes and by the transducer amplifier gain when used as a detector of reflected waves. Suitable values for the control variables result in reflections from obstacles only being detected in a spatial beam which can have a constant cross section independant of the distance of the reflecting object.

Abstract: Echo locating apparatus for a vision-impaired person which includes: a sound emitter for emitting a stream of sound bursts of ultrahigh frequency; at least one receive channel having a microphone for receiving echoes of the sound bursts and generating echo signals; an echo profile detector for generating an echo profile signal of each echo signal; a delay circuit for adding a variable delay to the echo profile signal, wherein the variable delay increases with the distance to the reflecting at a diminishing rate of increase. The sound burst emitter is preferably arranged to emit a beam of sound bursts having a given beam angle that can be pointed in any direction.

Abstract: An ultrasonic energy detector advantageously supplies both frequency and amplitude information which is related to the ultrasonic frequency and the amplitude of the detected ultrasonic energy. Frequency division is employed to reduce the relatively broad range of ultrasonic frequencies into a narrower audio frequency range while still providing information useful to identify the ultrasonic energy by frequency detection. The effect of anticipated background noise at all levels of gain selected is eliminated by subtracting a signal representative of the anticipated background noise and proportional to the selected predetermined gain from the amplitude of the detected ultrasonic energy.

Abstract: A supersonic bone conduction hearing aid that receives conventional audiometric frequencies and converts them to supersonic frequencies for connection to the human sensory system by vibration bone conduction. The hearing is believed to use channels of communications to the brain that are not normally used for hearing. These alternative channels do not deteriorate significantly with age as does the normal hearing channels. The supersonic bone conduction frequencies are discerned as frequencies in the audiometric range of frequencies.

Abstract: Ultrasonic echo ranging techniques and voice synthesis are used to provide a cost-effective convenient means of determining aircraft altitude during the landing phase of flight to overcome parallax problems, thereby to permit proper flare out, while maintaining constant visual contact down the runway during the landing procedure. In one embodiment a visual height indication or audible altitude annunciation is provided by through-the-air sonar ranging, with the display changing or an annunciation made only when the plane descends through predetermined altitudes such as 50, 25, 15, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0 feet. In the above embodiment the height is called out by converting a number representing height to a number which is audiblized in a human voice. This height annunciation technique may also be used with microwave range detection apparatus. In various embodiments, the altitude call outs may be periodic, for predetermined changes in altitude, or upon reaching predetermined heights above the runway.

Abstract: The echo ranging system of the invention comprises circuit means to diffetiate between shadows cast by objects and the period of time prior to the receipt of the first bottom return, as well as the lack of bottom reverberation for other reasons. Additional circuit means determines if the length of the shadow signals in comparison to their range exceeds a predetermined value. Circuit means are also included to produce a first electrical signal when such shadow signals are received. Further circuitry analyzes the shadow signals for which the first electrical signals were provided and produces a second electrical signal when said object shadow signals exceed in number or length a predetermined value. Additional circuit means are provided to convert said first and second electrical signals to suitable audible signals which may be readily distinguished, one from the other.

Abstract: A device assists in target acquisition by an operator in a weapon system comprising a target detection and locating system that delivers target-locating data, said device comprising means to synthesize stereophonic signals intended for the operator and means to convert target-locating data into data controlling the synthesis of stereophonic signals so that the operator is given a subjective sensation of a direction of attack corresponding to the actual direction of the target with respect to this operator.

Abstract: A method and apparatus is provided for alerting the operator of a vehicle as to the distance from the rear of the vehicle to a structure such as a loading dock to which the vehicle is being backed through the utilization of sonar ranging and means for converting a detected range into an audible call out of the distance from the back of the vehicle to the structure to which the vehicle is being backed. In one embodiment the talking unit is activated upon the placing of the vehicle in reverse gear. When used on trucks, the transducer is removably mountable to the rear of the truck, with a transmission line lead to the cab of the truck. In the preferred embodiment, a 50 kH.sub.

Abstract: An arrangement for aligning an antenna by determining an extreme value maximum or minimum of a predetermined physical dimension which is dependent on the alignment of the antenna. A voltage is generated in proportion in the magnitude of the physical parameter or dimension, and this voltage is applied to a voltage-to-frequency converter which converts this voltage into an acoustical signal. This acoustical signal has a frequency which is inversely proportional to the voltage. The acoustical signal is applied to the control input of an electronic switch which is actuated by an oscillator. Groups of pulses in the output signal from the oscillator are obtainable at the output of the electronic switch, in synchronization with the acoustical signal. When the antenna is misaligned, the acoustical signal has a relatively high frequency, while the voltage has a relatively low level.

Abstract: A system for measuring the distance to an object and orally announcing the measured distance by use of a speech synthesizer. The system includes a transmitter, a receiver, and a transmit/receive transducer operating at an ultrasonic frequency. The round trip time from generation of impulse to receipt of the echo reflected from an object is measured using a counter. The counter directly accesses a memory that contains the information needed to select the correct combination of words to be synthesized for the corresponding measured distance. The required vocabulary producing natural sounding speech is stored in a second memory within the speech synthesizer.

Abstract: A direction-finding system for localization of reflection-causing interfaces in the human body, in particular those of concretions, consists of at least one transmitter (18) emitting pulsed ultrasound and at least two ultrasound receivers (2, 3), of gate circuits (25) associated with each receiver, with variable amplifiers (26), and respective storage media (6) for ultrasonic echo signals (22, 21), and of a following device for sweep magnification (7) consisting of signal memories for readout at an adjustable clock frequency, there being provided variations of the delay differences ML and of the amplitude frequency spectra MF adjustable independently of each other. Connected downstream are devices for auditory direction finding (8, 9, 10, 15).

Abstract: A tactile hearing aid has electro-mechanical transducers which emit vibrations to the sense of touch of the skin surface for the transmission of signals. The transducers are small and lightweight and have low power consumption. The vibratory member is composed of piezoelectric, high-polymer material and has the form of a film which is provided with electically conductive coatings at both sides between which the signals to be transmitted can be applied. The film may be bent to form a ring and may be arranged in a folded stack of a number of plies to the outside surface of a carrier ring which is approximately 90.degree. open. The transducer can thus be worn on the fingers of a hand. The transducer unit is employable with particular advantage in devices for the transmission of messages via the sense of touch such as in hearing prothesis for persons extremely hard of hearing or for deaf persons.

Abstract: A method for processing a reflected echo signal which is received from an object and supplied to an ultrasonic binaural sensory aid comprising the step of stretching said reflected signal in time axis, and the step of converting the stretched signal into a signal of audible frequency, and a blind aid which works by the above mentioned method.

Abstract: Apparatus is provided for adapting an analog depth sounder for the calling out of the depth at regular time intervals. In one embodiment, a self-contained adapter module is mounted to the face of the depth sounder so as to cover the depth sounder display, with the module including a transparent plate carrying a detector array and with electronics and speaker carried at the center of the array. In this embodiment, the detectors are arranged in thin radially extending lines to permit accommodation to displays of different diameter. Alternatively, small detectors are arranged along a circle having a diameter which overlies at least a portion of the orbiting radiating element which radiates along a considerable length. This alternative array configuration also accommodates a range of display diameters. As a further alternative, to accommodate different diameter displays, the thin line detectors may be replaced with radially extending light pipes with detectors at their ends.

Abstract: Apparatus is provided for adapting an analog depth sounder for the calling out of the depth at regular time intervals. In one embodiment, a self-contained adapter module is mounted to the face of the depth sounder so as to cover the depth sounder display, with the module including a transparent plate carrying a detector array and with electronics and speaker carried at the center of the array. In this embodiment, the detectors are arranged in thin radially extending lines to permit accommodation to displays of different diameter. Alternatively, small detectors are arranged along a circle having a diameter which overlies at least a portion of the orbiting radiating element which radiates along a considerable length. This alternative array configuration also accommodates a range of display diameters. As a further alternative, to accommodate different diameter displays, the thin line detectors may be replaced with radially extending light pipes with detectors at their ends.

Abstract: Apparatus is provided for adapting an analog depth sounder for the calling out of the depth at regular time intervals. In one embodiment, a self-contained adapter module is mounted to the face of the depth sounder so as to cover the depth sounder display, with the module including a transparent plate carrying a detector array and with electronics and speaker carried at the center of the array. In this embodiment, the detectors are arranged in thin radially extending lines to permit accommodation to displays of different diameter. Alternatively, small detectors are arranged along a circle having a diameter which overlies at least a portion of the orbiting radiating element which radiates along a considerable length. This alternative array configuration also accommodates a range of display diameters. As a further alternative, to accommodate different diameter displays, the thin line detectors may be replaced with radially extending light pipes with detectors at their ends.

Abstract: A system is disclosed that includes an audio signal generator to provide a distinguishable audible output that varies in accordance with a monitored input. The audio signal generator varies a parameter of the audible output, such as frequency or amplitude, in n discrete steps corresponding to a range of variation in value of the monitored input. A plurality of different inputs may be monitored, and an audio signal generated therefrom having a plurality of different parameters, each of which corresponds to an individual one of the monitored inputs. The monitored inputs may be heart rate, systolic blood pressure, diastolic blood pressure, and body temperature. The audio signal produced may be composed of a series of recurring pulses, the parameters of which corresponding to the different monitored inputs are amplitude of each pulse, time duration of each pulse, time duration between the onset of successive pulses, and the frequency of the signal that defines each pulse.

Abstract: A sonic ranging and/or object detection system, particularly useful for the blind, periodically employs widely different pulse frequencies in order to distinguish between objects located directly in front of the energy transmitting portion of this system and those located to either side. The higher frequency pulses produce a relatively narrow sonic energy beam width for detecting centrally located objects and the lower frequency pulses produce a relatively broad sonic energy beam width for detecting lateral or off-center objects. One or more time-related audible tones are superimposed on each of the pulse frequencies for range determining and/or object distinguishing purposes.

Abstract: Apparatus is provided for adapting an analog depth sounder for the calling out of the depth at regular time intervals. In one embodiment, a self-contained adapter module is mounted to the face of the depth sounder so as to cover the depth sounder display, with the module including a transparent plate carrying a detector array and with electronics and speaker carried at the center of the array. In this embodiment, the detectors are arranged in thin radially extending lines to permit accommodation to displays of different diameter. Alternatively, small detectors are arranged along a circle having a diameter which overlies at least a portion of the orbiting radiating element which radiates along a considerable length. This alternative array configuration also accommodates a range of display diameters. As a further alternative, to accommodate different diameter displays, the thin line detectors may be replaced with radially extending light pipes with detectors at their ends.

Abstract: An ultrasonic ranging device for use in a vehicle having a high frequency oscillator supplying continuous sine wave signals to a power amplifier through a first gate controlled by a timer. A second gate controlled by the timer supplies an amplified sine wave signal from the power amplifier to a piezoelectric transducer mounted on an exterior portion of a vehicle. The transducer produces a series of repeated ultrasonic pulses and receives echoes from nearby objects converting the echoes into electrical return signals. A receiver amplifies the return signals and supplies them to a coincidence gate, which is enabled for relatively short time intervals by a timer. The coincidence gate supplies an output signal to an indicator when the return signal is detected during the interval that the gate is enabled.

Abstract: A method of and apparatus for locating an object by stress wave energy reflection in which the wave energy is transmitted as a beam by transmitting transducer elements, and is scanned through successive sectors of a field of view by imposing differential transmission delays on transmitting signals fed to the elements by means of a delay line. Indicator signals are developed in receiving channels connected respectively to receiving transducers providing binaural characteristics, and transducer providing monaural characteristics but collectively covering the field. An indicator means comprises any, or any combination, of audible means, visual means or tactile means the two latter providing coordinate displays.

Abstract: An airplane flies through the air because the forward speed of its wings through the air produces lift which is greater than the total weight of the craft. When the forward speed decreases below a certain amount, there is insufficient lift to counteract the weight of the plane and the plane will drop down (or stall). This is the ideal condition of speed at which an airplane lands, but it is important that the stall occur when the plane is only a very short distance (like three feet) above the ground. It is also very important that the plane remain well above the ground or other obstacles until a suitable landing field is reached.The device herein described uses "sonar" or reflections of sound pulses to give the pilot an audible indication of his exact distance from the ground so that he can know the correct moment to stall or "flare" the plane for a perfect landing.

Abstract: A conventional mobility cane for the blind incorporates a compact, dual-mode, ultrasonic obstacle detection sensor that includes a combination transmitting and receiving, capacitance type electrostatic transducer. The size of the protective zone associated with said sensor is infinitely variable. In one mode, the sensor warns of low lying objects that might contact the upper extremities of an ambulatory mobility cane user. In another mode, the user can determine the presence or absence of more remote objects. Means are provided for readily alternating between said object sensor modes.

Abstract: An improved method and apparatus for determining the length of a tubular member from a selected end thereof utilizing a hand-held probe wherein means are provided for producing sound pulses at the selected end, means are provided for detecting sound pulses at the selected end, means are provided for sensing the ambient temperature of the air in the vicinity of the inside of the tubular member being measured, means are provided for determining the time elapsed from the moment the sound pulse is generated until the accoustic wave comprising the returning sound pulse is detected by the detecting means, and means are provided for compensating for the increased travel time of the sound pulse occasioned by the sound pulse being reflected from the impedance differential surface set up by the other end of the pipe and spaced from the other end of the pipe.

Abstract: A system for measuring distance to an object. The system comprises a device for producing a high frequency sound impulse. There is a receiver for a high frequency echo sound impulse reflected from the object. A depth clock is connected to clock a counter. An initiator for the depth clock initiates the clock at a first time corresponding to the time of production of the high frequency sound impulse. The depth clock is stopped at a second time corresponding to the time of receipt of the echo sound impulse. The content of the counter is proportional to the distance to the object. A timer prevents stopping of the depth clock until a predetermined delay after the first time. A speech synthesizer produces spoken numbers corresponding to data supplied to the speech synthesizer. Data corresponding to the content of the counter are supplied to the speech synthesizer. The system is safer than prior art systems as it does not need to be observed.

Abstract: A marine depth sounding apparatus including a floatable housing carrying a sonic transducer for emitting sound waves toward the bottom of a body of water and for detecting the reflections of such sound waves, and a sound transmitter for emitting an audible signal when the information provided by the sonic transducer indicates that the depth of the water is less than a predetermined depth. The apparatus may be cast away from the vessel to provide information concerning the depth of water at locations remote from the vessel. A circuit is disclosed for comparing the time period required for sound waves to travel a distance corresponding to the predetermined depth with the actual time elapsed between the emitting of the sound waves by the sonic transducer and their detection by the sonic transducer.

Abstract: A seabed referenced fish detection system for detecting aquatic animals within a predetermined zone relative to the bottom of a body of water. Preferably, fish are detected within a predetermined zone contiguous with the bottom without the need for range switching to accommodate changes in depth. A pair of ultrasonic pulses are transmitted, preferably of different frequencies, and separated by a predetermined time delay. The bottom echo from the first ultrasonic pulse initiates a gate interval during which echoes from the second ultrasonic pulse are detectable. When the time delay and the gate interval are equal, the gate interval terminates immediately before the reception of the second bottom echo, so that only echoes from above the bottom, e.g., fish echoes, can trigger an audible output signal. Since fish detection events are un-ambiguously indicated by an audible signal, the need for a graphic recorder or C.R.T. to distinguish and interpret fish and bottom echoes is eliminated.

Abstract: A method of and apparatus for locating an object by stress wave energy reflection in which the wave energy is transmitted as a beam by transmitting transducer elements, and is scanned through successive sectors of a field of view by imposing differential transmission delays on transmitting signals fed to the elements by means of a delay line. Indicator signals are developed in receiving channels connected respectively to receiving transducers providing binaural characteristics, and transducer providing monaural characteristics but collectively covering the field. An indicator means comprises any, or any combination, of audible means, visual means or tactile means the two latter providing coordinate displays.