Abstract: Disclosed herein is an apparatus for detecting infrasound. The apparatus for detecting infrasound includes a sound wave detector including a diaphragm dividing an inner space of a first container into a first space and a second space, and a microchannel assembly including a second container having an inner space with one of the spaces divided by the diaphragm and a plurality of microchannels having different resistance values with respect to transmission of a sound wave, and exposing the inner space of the second container to the air through one of the plurality of microchannels. Such an apparatus for detecting infrasound may have various cut-off frequencies according to the number of the microchannels.

Abstract: Providing indoor location, position, or tracking of a mobile computer is disclosed. Outdoor location, indoor location, and determined motion information is used to track the mobile computer indoors.

Abstract: To enable precise calculation of a propagation time of a direct wave which arrives the earliest from an ultrasonic emission source without being affected by a reflected wave. A plurality of ultrasonic signals generated based on a plurality of M sequences different from each other are propagated from a transmission side to a reception side, whereby the reception side executes processing of correlation between each model waveform of the plurality of M sequences and a waveform of each ultrasonic signal and detects a subsidiary peak of a correlation value appearing when both waveforms partly coincide with each other to, starting with the smallest one of subsidiary peaks detected by all the correlation processing, determine a plurality of corresponding M sequences.

Abstract: A computer implemented method for discriminating between launch and impact events using acoustic sensors.

Abstract: To enable precise calculation of a propagation time of a direct wave which arrives fastest from an ultrasonic generation source without being affected by a reflected wave of an ultrasonic signal. A plurality of ultrasonic signals generated based on a plurality of M sequences different from each other are propagated from a transmission side to a reception side, whereby the reception side generates model waveforms of the plurality of M sequences, executes correlation processing between each model waveform and a waveform of each ultrasonic signal and detects a secondary peak of a correlation value which appears when both waveforms partly coincide with each other to determine an M sequence which generates a smallest secondary peak among secondary peaks detected by all the correlation processing as an optimum M sequence.

Abstract: A method for calculating coordinate values of a measuring machine is provided. The method includes receiving signals in three dimensions from a raster ruler signal generator, identifying a direction of each signal and multiply a frequency of each signal. The method further includes counting each of multiplied signals in each dimension, sending the counted data to the MCU. The method further includes adding the counted data of each of the multiplied signals in each dimension to obtain an accumulated number in each dimension and calculating coordinate values of the measuring machine according to the accumulated number in each dimension and a proportionality factor of the raster ruler signal generator.

Abstract: An apparatus and method is disclosed for determining the position of a user interface mouse using time of arrival measurements. A transmitter transmits a signal to an array of receivers that are spatially separated from one another. The time difference of arrival for is found for each receiver relative to a predetermined reference receiver. Using the time difference of arrival (TDOA) of each receiver, the location in 3-dimensional space of each receiver, and the speed of sound the position of the transmitter in 3-dimensional space relative to the reference receiver may be found.

Abstract: A touch pad (101) includes transducers (201-204) for receiving acoustic signals resulting from touch events, such as the continuous movement of a fingertip across the surface (105) of the touch pad. The acoustic signals are acquired at different transducer locations in the surface. Signals from different transducers are combined, preferably in antiphase, to improve signal characteristics. The transducer signals are supplied to a stereo analogue to digital converter (407). Phase differences (706) are obtained and compared (703) with phase difference profiles (607) of known location, in order to identify the location of the touch event. An index (606) is used to identify candidate locations to reduce the amount of processing. Interpolation (705) is used to locate the touch event between profile locations.

Abstract: A planimeter includes a movable housing in which are mounted orthogonally aimed x- and y-position sensors. Each position sensor comprises a piezoelectric ultrasound transmitter and receiver for sending ultrasound to a reflector disposed on a drawing and sensing resultant echoes. Circuitry in the housing computes from the sensor outputs the housing's position for each of a sequence of locations on a drawing at which a user positions the housing, and from those it computes scaled distances between those positions as well as quantities that can be derived from those distances. The transmitter's and receiver's respective positions with respect to positioning crosshairs are such as to suppress the results of orientation errors. The planimeter's handle is angled at 45° to the directions in which the sensors are aimed so that it lends itself to both right- and left-handed operation.

Abstract: The invention relates to a device that is used to analyse the structure of a material. The inventive device comprises: probe elements (5) which are used to (i) emit a wave, in the material, with emission delay laws that correspond to several simultaneous deviations and (ii) receive, on the different probe elements (5), signals from the refraction of said wave by the material; detection channels, each detection channel being connected to a probe element (5), in order to collect the refraction signals and to transmit same to data processing means (4); and delay circuits that apply a delay on each detection channel according to the reception delay laws which are predetermined and which correspond to the different deviations of the wave emitted. The invention also relates to an analysis method which can be used, in particular, on said device.

Abstract: A method of detecting and localizing a source of partial discharge in an electrical apparatus placed in an enclosure containing an acoustically-conductive fluid.

Abstract: A primary transceiver of a primary vehicle transmits a first transmission signal to a first transponder and a second transponder associated with a secondary vehicle. A first transponder antenna and a second transponder antenna are associated with secondary vehicular reference points. Upon receipt of the first transmission signal, the first transponder transmits a second transmission signal to a first beacon of the primary vehicle and the primary transceiver. A transmitter antenna and the first beacon antenna are associated with primary vehicle reference points. Upon receipt of the first transmission signal, the second transponder transmits a third transmission signal to the first beacon and the primary transceiver. A data processor or estimator determines propagation times associated with the first transmission signal, the second transmission signal, and the third transmission signal.

Abstract: An apparatus for ultrasonically detecting an edge of a web, includes a ultrasonic-wave transmitter transmitting ultrasonic-wave pulse train, a ultrasonic-wave receiver receiving the ultrasonic-wave pulse train and converting the received ultrasonic-wave pulse train into electric signals, the web being fed between the ultrasonic-wave transmitter and receiver, a rectifying circuit for rectifying the electric signals, a low-pass filter circuit for smoothing output signals transmitted from the rectifying circuit, a first sample-holding circuit for sampling an output signal transmitted from the low-pass filter circuit, at first timing, a second sample-holding circuit for sampling an output signal transmitted from the low-pass filter circuit, at second timing later than the first timing, a third sample-holding circuit for sampling an output signal transmitted from the first sample-holding circuit, at the second timing, and a differentially amplifying circuit for calculating a difference between output signals trans

Abstract: An apparatus for providing Global Positioning System (GPS) position data to an underwater diver for use in navigation is comprised of a SCUBA Flag/Antenna Float, positioned on the surface of the water, containing a Spring-loaded Cable Reel which is connected via a Signal Umbilical Cable to a GPS Capsule carried by the underwater diver. A GPS Antenna and power supply provide a signal to a GPS Receiver/Display which is encased in the GPS Capsule. The diver views icons displayed on the GPS Receiver to determine his/her current position in relation to previously entered waypoints, or geographical coordinates, such as a wreck, dive boat, or locations of interest plotted by the diver during the dive. The position information displayed by the GPS receiver enables the diver to navigate to and from the various locations or geographical coordinates while submerged.

Abstract: A plurality of sound-detecting devices are configured to detect sound from an event of interest. Information about the sound is recorded that is dependent on a distance between the source position and the location of the sound-detection devices. The source position is approximated using the recorded information and the relative position of individual sound-detection devices to one another. The approximated source position is used as input for operating a electronic device.

Abstract: A method and apparatus for determining accurately a coordinate of a transmitting/receiving antenna pair relative to a predetermined reference position. The method includes placing a transmitting antenna in proximity to a reflective strip, transmitting a first signal from the transmitting antenna and detecting a reflection of the first signal received from the reflective strip at the receiving antenna located at a fixed distance from the transmitting antenna. The method further comprises determining a coordinate of the antennas relative to the reflective strip based on a parameter of the reflection. The method may further comprise detecting a second signal received by the receiving antenna from a conductive strip located proximate to the reflective strip, and determining a second coordinate of the antennas based at least on a time difference between transmitting the first signal from the transmitting antenna and receiving the second signal at the receiving antenna.

Abstract: A presence detection system includes a reader device attached to a first body, and a tag device attached to a second body. The reader device has an ultrasonic transducer for generating and transmitting ultrasonic pulses at a first rate of occurrence; an RF receiver for receiving a RF signal; and a microcontroller coupled to the ultrasonic transducer and the RF receiver for receiving signals from the ultrasonic transducer and the RF receiver and for controlling the operation of ultrasonic transducer and the RF receiver. The tag device has an ultrasonic receiver for receiving ultrasonic pulses from the ultrasonic transducer of the reader device; and an RF pulse generator for generating and transmitting an RF pulse.

Abstract: An underwater object positioning system comprises a workboat, an acoustic transmitter-receiver mounted on the workboat, first and second surface tow units towed by the workboat, an acoustic transducer that is mounted on the first surface tow unit, that is connected by a communication cable to the acoustic transmitter-receiver on the workboat and that is positioned by a radio positioning means; two acoustic receivers that are mounted on the second surface tow unit, that are connected by a communication cable to the acoustic transmitter-receiver on the workboat and that are positioned by a radio positioning means. An acoustic pulse transmitter is mounted on a submerged positioning target. A processor unit on the workboat calculates the location of the submerged target based on data showing the positions of the transducer and receivers, and the distances from the transducer and receivers to the acoustic pulse transmitter.

Abstract: A method and apparatus using ultrasonic sensors for determination of the pointing vector described by two points separated in space in the coordinate frame of the measuring system. For measurement, acoustic signals are transmitted from two emitters whose spatially separated coordinates form the desired pointing vector. Three detectors, associated receiver electronics and software are required to compute six distinct spheres from the time of flight measurements. The intersection of the three spheres, associated with each emitter, describe the desired location in the detector coordinate system of that emitter. With the coordinates of each emitter, the pointing vector is computed using standard geometry. A reference is required to determine the time of flight of the signals to each detector. Another embodiment uses an active reflective technique, where the timing is obtained through round trip transmission and reception of the signal with a known fixed delay at the vector points.

Abstract: A method of tracking an object within a surveillance area having a predetermined linear extent. One or more ultrasound transducers are fixed to the object. A plurality of background units are placed at known positions in the area, each unit including an ultrasound transducer. One or more ultrasound waves are transmitted between the object and the plurality of background units. The ultrasound waves are received if they have propagated between the object and the background units within a time window of a duration such that the product of the duration and the speed of sound is substantially less than the linear extent of the detection area. A characteristic of the received ultrasound waves is determined, and coordinates of the object are determined responsive to the characteristic.

Abstract: The present invention is generally directed to a method of remotely controlling electronic devices by using the change in time required for sound waves to travel from an emitter to a detector. The time needed for emitted sound waves to reach a detector depends on the distance from the emitter to the detector. The present invention uses a system which measures the time between emission and detection of two or more successive sound pulses or sound waves. The change in time for sound waves to travel the distance from the emitter (or emitters) to the detector (or detectors) is determined and then used for controlling electronic devices. The sound waves are produced by a sound generator, and the detector is designed specifically for the detection of sound waves. In certain embodiments, ultrasonic sound waves or pulses are produced by the sound generator and are used to control an electronic device such as a computer cursor or vehicle.

Abstract: The present invention detects coordinates of a designated point and includes a vibration transmission plate having anisotropic properties such that vibrations from a vibration generation source applied to the vibration transmission plate propagate through the vibration transmission plate with differing vibration transmission velocities depending on a direction of transmission of vibration. A plurality of vibration detection units are provided for detecting vibrations transmitted through the vibration transmission plate, and a determination unit determines coordinates of the vibration generation source by measuring time periods of propagation of vibrations through the vibration transmission plate from the vibration generation source to one or more of the vibration detetion units.

Abstract: A system to accurately and rapidly present the location of gunfire or other explosive events to dispatchers uses a sparse set of distributed acoustic sensors mounted on rooftops or utility poles to allow triangulation of the gunfire sounds. If a fourth signal confirms that an explosive event occurs at a position triangulated from three other signal, then the system announces an event to dispatchers. The system tests various sensor triads against various criteria and selects the best triad for making the triangulation calculation. In the case where multiple gunshots are present, the system can automatically determine a velocity, thus helping identify and respond to drive-by shootings. The system presents a confirmed location on a computer map of the protected community showing where on a specific property the gunfire occurred. The dispatchers can listen to the event and can view wave forms or spectra to assist in discriminating gunshots from other explosive events.

Abstract: Three dimensional wireless pointing device for calculating coordinates and controlling a position of a cursor in a three dimensional space is disclosed, including a transmission side having a plurality of ultrasonic wave generating parts and a single infrared ray emitting part or a single ultrasonic wave generating part and a plurality of infrared ray emitting parts arranged in a certain axis direction at certain angles and a reception side having a plurality of infrared ray receiving sensors and a single ultrasonic wave receiving sensor arranged to cross the ultrasonic wave generating part(s) and the infrared ray emitting part(s) in the transmission side at a right angle, thereby to measure intensities of the infrared ray(s) and the ultrasonic wave(s) varied depending on direction of pointing and calculate a difference of relative traveling time periods of the infrared ray and the ultrasonic wave to obtain coordinate values of a position in a three dimensional space, whereby a position of cursor or menu, whi

Abstract: An elastic wave position-sensing device comprising a piezoelectric substrate, an input interdigital transducer T formed on an upper end surface of the piezoelectric substrate, and an output interdigital transducer R formed on the upper end surface of the piezoelectric substrate such that the finger direction of the interdigital transducer R is slanting to that of the interdigital transducer T by an angle .alpha.. The thickness d of the piezoelectric substrate is smaller than an interdigital periodicity P of the interdigital transducer T. An interdigital periodicity P.sub.N along the vertical direction to the finger direction of the interdigital transducer R is equal to the product of the interdigital periodicity P and cos .alpha.. An overlap length L.sub.P along the finger direction of the interdigital transducer R is equal to the product of an overlap length L of the interdigital transducer T and sec .alpha..

Abstract: Disclosed is a coordinate input device, having a vibration transmission plate, that simplifies the measurement of a vibration transmission speed, which is used as a known constant to calculate a distance between a vibration input location and individual vibration sensors, and that ensures the accurate performance of calculations to acquire input coordinates. According to the present invention, a vibration transmission plate has anisotropic properties that are associated with two axes. As a result, the speeds at which vibrations arrive at vibration sensors differ depending on which pair of vibration sensors, 6a and 6d, or tb and 6c, is involved. Therefore, the vibration transmission speeds are measured for the individual pairs of vibration sensors, 6a and 6d, and 6b and 6c, and the measured values are stored as known values. These values are employed as constants to be used for calculations performed to acquire coordinates.

Abstract: A collision avoidance system for a vehicle has a vehicle steering sensor for sensing a direction in which the vehicle is being steered, a source of radiation, an articulated reflector for directing radiation from the source in a desired direction, an articulation mechanism for effecting articulation of the articulate reflector, and a close loop control circuit responsive to the vehicle steering sensor for controlling the articulation mechanism so as to cause the articulated reflector to direct radiation in a direction which is generally the same as that direction in which the vehicle is turning.

Abstract: A digitizer uses acoustic waves originating from a stylus to determine the position of the stylus on a plate. The acoustic waves are introduced into the plate from the tip of the stylus and are detected by a plurality of detectors positioned at various points along the periphery of the plate. By sensing differences in the arrival times of the acoustic waves at the detectors, a microprocessor calculates the position of the stylus. In a preferred embodiment using a non-tethered stylus, four detectors are positioned at the corners of a rectangle, and the time differences are used as addresses in a lookup table, which is programmed to contain x and y coordinates corresponding to the time differences, Different embodiments may detect only the "fast" symmetrical waves or only the "slow" antisymmetrical waves generated in the plate, or may use the arrival times of both types of waves to determine the stylus position.

Abstract: An ultrasonic coordinate input, apparatus comprising a plurality of ultrasonic wave receivers to receive ultrasonic wave emitted by a cordless ultrasonic pen and propagating in an ultrasonic propagating medium, a plurality of receiving circuits for detecting the rising edges of received signals of the ultrasonic wave receivers, a measuring circuit for measuring the difference in time of receiving ultrasonic wave between the ultrasonic wave receivers and a calculating circuit for calculating the coordinates of ultrasonic wave input position according to the result of measurement. When the receiving circuits, the measuring circuit and the calculating circuit are installed together with the ultrasonic wave receivers on the ultrasonic propagating medium, the entire apparatus can be made small in size.

Abstract: A method and apparatus for determining position of a vehicle in a tank of fluid. At least one transducer is disposed on the vehicle and a plurality of transducers are disposed on the outside wall of the tank. The transducers are arranged in a substantially common plane. The travel time of energy can be measured between any two of the transducers. Accordingly, the velocity profile of the liquid can be determined based on travel times measured between the transducers on the tank and position can be determined based on travel times measured between the transducers on the vehicle and the transducers on the tank.

Abstract: A three-dimensional measurement method and device are intended for fast and accurate measurement of large objects such as vehicles. The method includes the steps of determining approximate measurement positions of a shape measurement sensor; positioning the sensor at successive approximate measurement positions to read off the shape of surface portions of the object represented by points on the object whose co-ordinates are expressed in a system of axes fixed relative to the sensor; identifying accurate positions of the sensor at the approximate measurement positions relative to a predetermined fixed system of axes; and converting the co-ordinates of the points of the surface portions expressed in the system of axes fixed relative to the sensor into co-ordinates expressed in the fixed system of axes on the basis of the identified accurate positions of the sensor.

Abstract: A shift of an input coordinate by a change in temperature in a coordinate input device is prevented. An arithmetic operation and control circuit 1 applies a drive signal to a vibration pen 3 and starts a timer. The drive signal applied to the vibration pen 3 is delayed by a delay circuit 12, which drives a vibrator drive circuit 2 to generate vibration. A delay time of the delay circuit 12 is shortened as a temperature rises and a sum time of the delay generated by the delay circuit 12 and a delay generated in the vibration pen 3 as the temperature changes is constant regardless of the temperature. As a result, a vibration propagation time measured by the timer represents a net propagation time plus a constant delay time regardless of the temperature. Thus, the stable coordinate input is assured regardless of the temperature.

Abstract: An acoustic touch position sensor having a transducer which imparts a wave, propagating along a first axis. A reflective array disposed along the first axis which reflects the wave as a set of waves having a horizontally polarized component and a non-uniform volumetric energy density along an axis normal to said surface, traveling along a different axis into the touch surface region of the substrate. The waves are partially absorbed, attenuated or perturbed by an object touching the substrate, to create a modified waveform having characteristics indicative of the axial displacement and/or contact condition of the object with the substrate. The wave perturbation is detected by collecting the set of waves with a reflective array, which redirects the wave energy to a receiving transducer. The transducers preferably produce and are responsive to Rayleigh type waves, with the reflective arrays mode-converting acoustic wave energy between higher order horizontally polarized shear waves and Rayleigh type waves.

Abstract: A piezoelectric sensor for detecting elastic plate vibrations in an object such as the transmission plate in a coordinate input apparatus is prismatic in shape and is fixed to the surface of the object. The prismatic sensor is arranged so that it is parallel to the direction of propagation of the vibrations and has an electrode surface perpendicular to the surface of the object. The arrangement of the prismatic sensor permits the thickness of the object in which the plate vibrations propagate to be substantially reduced and reduces the manufacturing cost of coordinate input apparatus using the prismatic sensor.

Abstract: A method is described for providing an estimate of the state of a moving contact. The method comprises providing a device for estimating the state of the contact, inputting information about a location of an observer platform at particular time intervals and information from at least one sensor about a position of the moving contact relative to the observer platform at each time interval into the device, transforming the inputted information into a series of geographical grids with one grid being formed for each reading of the at least one sensor; combining grids corresponding to similar time intervals into a series of consolidated grid representations; and analyzing the series of consolidated grid representations to produce an estimate of the state of the contact at a final point in time where an observation was made.

Abstract: A method of locating an acoustic emission source in a structure by reverse ray tracing. An azimuth acoustic emission sensor is utilized which has an array of individual elemental detectors which independently and sequentially respond to the passage of an acoustic stress wave. The response of each element of the array is electronically monitored, and individual responses to the acoustic stress wave are analyzed to determine the azimuth approach angle of the wave to the azimuth acoustic emission sensor. An accurate measurement of the true location of the acoustic emission signal source is then provided by reverse ray tracing by using a parallel processing arrangement having a plurality of parallel processing elements. The structure is modeled in the computer on a one to one basis, with each parallel processing element simulating and having structural data on one discrete area of the structure.

Abstract: An acoustic wave touch panel is shown for use with a non-active stylus. The acoustic wave touch panel includes an acoustic wave touch position sensor with an elastomeric substrate 20 overlying the touch position sensor and further including a stiff substrate overlying the elastomeric substrate. When a non-active stylus contacts a surface of the stiff substrate exerting a Z-axis force thereon, the Z-axis force is transmitted through the stiff substrate to the elastomeric substrate. The elastomeric substrate deforms in response to the Z-axis force and transmits the force to the acoustic wave touch sensor, the deformation of the elastomeric substrate absorbing or damping acoustic wave energy like a finger touch on the acoustic wave touch sensor.

Abstract: A system is provided for tracking the three-dimensional position of an object within a three-dimensional region by triangulation techniques to generate signals corresponding to such three-dimensional positions. The signals may be used to operate a variably operable system to create a virtual reality system. The triangulation means may comprise at least three ultrasound emitters cooperating with ultrasound receivers located on a body moving in the three-dimensional region. The signals are produced from multiplexed frequencies and/or intermediate signals may be projected using a triaxial accelometer.

Abstract: An apparatus is disclosed for determining the position of a moveable element over the surface of a solid medium. First and second transducer devices are provided and are moveable for placement at selected respective first and second locations on the surface for coupling with said surface. A third transducer device, for coupling with said surface, is mounted with the moveable element. Ultrasonic energy is transmitted, in either direction, between the third transducer device and the first and second transducer devices, the ultrasonic energy travelling through said solid medium. The transit times of the ultrasonic energy propagating, in either direction, between the third transducer device and the first and second transducer devices are determined, the transit times being indicative of the position of the third transducer device with respect to the first and second transducer devices.

Abstract: A coordinates input apparatus for detecting coordinate values of an arbitrary point by indicating the arbitrary point on a vibration transmission plate by a vibration input pen for generating a vibration, comprises: a plurality of sensors, arranged at predetermined positions in the vibration transmission plate, for detecting the vibration generated by the indication by the vibration input pen, for converting the vibration into electric signals, and for outputting; a measuring circuit to measure delay times from a time point when the arbitrary point has been indicated by the vibration input pen until time points when the electric signals are detected; an obtaining circuit to obtain origin correction data from a plurality of points on the vibration transmission plate; a memory to store the origin correction data; and a processor for reading out the origin correction data from the memory, for correcting the coordinate values on the basis of the delay times measured by the measuring circuit and the origin correct

Abstract: A controller for an acoustic wave touch panel includes a signal conditioning circuit that can receive and process X axis and Y axis sense signals from the touch panel where the touch panel can be configured with either one or two transducers per sense axis. The signal conditioning circuit includes a differential amplifier to which simultaneously received X axis and Y axis sense signals are applied to provide common mode rejection. The controller also includes a touch position detector that accurately determines the position and pressure of a touch without jitter, the touch position detector including a software low pass filter and peak detector for analyzing the output of the signal conditioning circuit.

Abstract: An acoustic touch position sensor is shown in which a transducer coupled to a side of a substrate imparts a shear wave into the substrate for propagation along a first axis. A reflective array disposed along the first axis reflects portions of the shear wave along a plurality of parallel paths extending across a touch surface of the substrate to a second reflective array the axis of which is parallel to the first axis. The second reflective array reflects the shear waves incident thereto a receiving transducer mounted on the side of the substrate. A touch on the substrate results in perturbation in the shear wave which is sensed to determine the axial position of the touch on the substrate. A laminated touch panel is provided such that a back plate of any desired thickness is bounded onto the substrate. A non-shear wave coupling adhesive may be used to bond the back plate to the substrate.

Abstract: A plurality of video cameras (7a-d) are mounted on a table which is adapted support a workpiece or other object to be measured, and the mounting of each camera to the table provides for controlled universal orientation of each camera via an articulating head having provision for selective rotation about each of two orthogonally related axes. The table is provided with vibration damping, whereby both the measured object, and the cameras which provide triangulation data for each measurement, can operate from the same rigid base, isolated from external sources of mechanical shock. The video signals of the cameras are fed, along with instantaneous optical-axis orientation data for each camera, to the computer of a coordinate-measuring machine.

Abstract: A detecting system and method of determining the position of a mobile point of interest in a m dimensional coordinate system having an ultrasonic transmitter mounted on the point of interest, and a plurality of stationary ultrasonic receivers, the number being at least m plus 2. The location of the receivers are determined optimally by using a linear matrix formulation. Alternatively, the location of the receivers can be determined during installation or self-calibration of the system. The system also includes receiver controlling means for processing the received signal to generate time of flight measurements which are used to eliminate the speed of sound as a variable and to compute the location of the point of interest. The controlling means also generates phase measurements when prompted by an outside source by comparing the transmitted signal with a 40kHz pulse sync to refine the accuracy of the location of the point of interest.

Abstract: An acoustic touch position sensor is shown in which a transducer coupled to a side of a substrate imparts a shear wave into the substrate for propagation along a first axis. A reflective array is disposed along the first axis to reflect portions of the shear wave along a plurality of parallel paths extending across a touch surface of the substrate to a second reflective array the axis of which is parallel to the axis of the first reflective array. The second reflective array reflects the shear waves incident thereto to a transducer mounted on the side of the substrate and responsive to shear waves propagated thereto for providing a signal representative of these shear waves. A touch on the substrate results in a partial absorption of the energy in the shear wave so as to produce a perturbation therein which is sensed to determine the axial position of the touch on the substrate.

Abstract: A coordinate input apparatus in which a vibration which was input by a vibration input pen is detected by vibration sensors attached to a vibration propagating plate such as a transparent glass plate or the like and the coordinates of the position of the pen on the plate are detected.

Abstract: A spatial measurement recovery system and method which determining the position, orientation, shape and/or operational characteristics of an environment. The system includes a data gathering apparatus and a model building apparatus. The data gathered may then be transformed into a CADD model of an as-built or as-is environment, or to otherwise map the environment in three dimensions.

Abstract: An ultrasonic digitizer pen includes an ultrasonic transmitter to transmit ultrasonic waves through the air, to illuminate a writing surface. An ultrasonic receiver receives the waves reflected off the illuminated writing surface. The writing surface is a mouse pad, a wooden tabletop or other surface having a natural amount of roughness to reflect ultrasonic waves in all directions.The transmitter and receiver are located in the pen near its tip and have radiation patterns pointing generally in the same direction, and parallel to the writing surface. At least one of the radiation patterns is narrow in a horizontal plane and wide in a vertical plane, to illuminate a narrow area of the writing surface.phase measuring circuit measures the phase difference between the transmitted and the received ultrasonic signals. This phase is indicative of the displacement of the digitizer pen.

Abstract: A coordinate input apparatus determines the coordinates of contact of a vibration pen with a vibration transmission plate by detecting vibrations from the pen through a vibration sensor. Constants required for measurement are generated in a constant determination circuit on the basis of vibration cycle measurements and a circuit measures the cycle of the detected vibrations from the vibration sensor using the determined constants. Automatic determination of constants eliminates inaccuracies due to component variations and reduces production costs and maintenance.

Abstract: A vehicle sensing system includes a data bus, a first microprocessor coupled to the bus and a plurality of sensor modules about a vehicle periphery for detecting the presence of objects within a predetermined range of distances of each of such sensor modules. Each sensor module of the vehicle sensing system includes a transducer, a second microprocessor, coupled between the transducer and the bus, for processing information received from the transducer, and a light emitting diode disposed on an outer surface of a housing for the transducer, coupled to the second microprocessor, for indicating when an object is within the predetermined distance of the sensor module or when the sensor module is faulty. Each sensor module further includes a temperature sensing circuit coupled to the second microprocessor and a bus transceiver for receiving information from the bus and for transmitting information to the bus.