WO2014019075A1 - Système de mise en concordance de pression acoustique active - Google Patents

Système de mise en concordance de pression acoustique active Download PDF

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Publication number
WO2014019075A1
WO2014019075A1 PCT/CA2013/000688 CA2013000688W WO2014019075A1 WO 2014019075 A1 WO2014019075 A1 WO 2014019075A1 CA 2013000688 W CA2013000688 W CA 2013000688W WO 2014019075 A1 WO2014019075 A1 WO 2014019075A1
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WO
WIPO (PCT)
Prior art keywords
measurements
model
wave
pressure field
processing
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PCT/CA2013/000688
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English (en)
Inventor
Patrice Masson
Nicolas Quaegebeur
Pierre-Claude OSTIGUY
Nicolas Beaudet
Philippe SARRET
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Socpra Sciences Et Génie S.E.C.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Application filed by Socpra Sciences Et Génie S.E.C. filed Critical Socpra Sciences Et Génie S.E.C.
Priority to CA2920406A priority Critical patent/CA2920406C/fr
Priority to US14/419,257 priority patent/US9750451B2/en
Publication of WO2014019075A1 publication Critical patent/WO2014019075A1/fr

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Classifications

    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
    • G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
    • G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
    • G06F3/041—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
    • G06F3/043—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means using propagating acoustic waves
    • G06F3/0436—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means using propagating acoustic waves in which generating transducers and detecting transducers are attached to a single acoustic waves transmission substrate
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B17/00—Measuring arrangements characterised by the use of infrasonic, sonic or ultrasonic vibrations
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L1/00—Measuring force or stress, in general
    • G01L1/25—Measuring force or stress, in general using wave or particle radiation, e.g. X-rays, microwaves, neutrons
    • G01L1/255—Measuring force or stress, in general using wave or particle radiation, e.g. X-rays, microwaves, neutrons using acoustic waves, or acoustic emission

Definitions

  • PCT Patent Application number PCT/CA2011/000254 filed on March 4, 2011 claiming priority from the US Provisional Patent Application serial number 61/310,996, published under WO/201 1/106890 on September 9, 2011 and entitled "METHOD AND APPARATUS FOR PROVIDING A STRUCTURAL CONDITION OF A STRUCTURE" is hereby incorporated by reference.
  • the present invention relates to a sensitive surface and, more particularly, to a surface that is sensitive to contact pressure and position of an object.
  • Touch screens that are most widely used today are based on capacitive surfaces, which require a matrix of semiconductor-based detection elements. While they address most of the current consumer electronics market, they are limited in many respects. Among other limitations, scalability of capacitive touch screen is limited by the high number of semiconductors required. In addition, capacitive touch screens usually require costly manufacturing environment and costly material. Typically, capacitive-based solutions are inadequate for pressure determination. [0006] Outside the consumer electronics market, other types of surfaces dedicated to pressure mapping are also used. For instance, a pressure mat can be used in conjunction with cameras to analyze behaviors of small animals (e.g., pain-related postural deficits). The pressure mat has a matrix of pressure detection cells.
  • Each cell is connected to a management unit and delivers a pressure measurement.
  • the pressure mat is difficult to maintain in working condition (e.g., fragile surface ill-adapted to animals) and presents scalability issues (e.g., required number of cells for an appropriate density, required number of input ports for the management unit, etc.).
  • scalability issues e.g., required number of cells for an appropriate density, required number of input ports for the management unit, etc.
  • a first aspect of the present invention is directed to a method for determining that a pressure field is applied on a structure.
  • the method comprises generating a plurality of acoustic waves within the structure using at least one wave generator and taking a plurality of measurements of the plurality of acoustic waves using at least one wave sensor.
  • the method also comprises determining that a pressure field is applied to a surface of the structure by processing the plurality of measurements.
  • the acoustic waves are scattered due, for instance, to the presence of the pressure field.
  • the wave generator and the wave sensor may, for instance, be piezoelectric elements. The piezoelectric elements may alternate between acting as the wave generator and acting as the wave sensor.
  • the structure may be a thin structure made of rigid or flexible material, planar or curved and may allow the acoustic wave to be propagated therein.
  • the acoustic waves may be propagated as guided waves.
  • Processing the measurements may further comprise obtaining a differential value between the measurements and comparing the differential value to a threshold.
  • Determining that the pressure field applied may further comprise processing the measurements using a model of acoustic wave propagation within the structure.
  • the model may, for instance, comprise propagation speed of the plurality of acoustic waves within the structure.
  • the model may be determined by processing the measurements before storing the model in a memory.
  • the model may be determined by performing a free-calibration while the structure is free of external pressure and/or by performing a loaded-calibration while an object of known characteristics is placed at a known location on the structure.
  • the model may also be based on theoretical or experimental results.
  • the method may further comprise providing a model and determining that the pressure field is applied to the structure at a location on the surface by processing the measurements from one or more wave sensors. The method may then also further comprise determining an amplitude of the pressure field at the location on the surface by processing the measurements. [0013] If, optionally, more than one wave sensor is provided, the method may further comprise providing a model comprising at least propagation speed of the plurality of acoustic waves within the structure and determining that the pressure field is applied to the structure at a location on the surface by processing the measurements from different wave sensors. The method may then also further comprise determining an amplitude of the pressure field at the location on the surface by processing the measurements from the different wave sensors.
  • correlating the measurements with the model retrieved from memory may further be performed in order to provide a mapping of the pressure field on the surface of the structure.
  • the method may further comprise determining that at least one object applies the pressure field on the structure. It may further be determined that the object applies the pressure field on the structure at more than one determined locations with an associated number of determined amplitudes.
  • the object may be one or more fingers and the determined locations and determined amplitudes may allow for fingerprint determination.
  • the location may be determined within a predictable location tolerancing and the amplitude is determined within a predictable amplitude tolerancing.
  • the method may further comprise approximating, from the determination, a position of the at least one object in three dimension.
  • the method may comprise obtaining a series of determinations over time.
  • the series of determinations may be used as an input to an electronic device. It may also be determined that at least one animal applies the pressure field on the structure. The series of determinations may then be used to evaluate behaviors of the animal.
  • the animal may be a mammal such as a rodent or a human.
  • a second aspect of the present invention is directed to an apparatus comprising a structure on which a pressure field is applied, a wave generator and a wave sensor.
  • the wave generator is for generating a plurality of acoustic waves within the structure.
  • the wave sensor is for taking a plurality of measurements of the plurality of acoustic waves.
  • the apparatus further comprises a processing module for determining that a pressure field is applied to a surface of the structure by processing at least two of the plurality of measurements.
  • the wave generator and the wave sensor can be piezoelectric elements. Each of the piezoelectric elements may further alternate between acting as the wave generator and acting as the wave sensor. [0019] Processing the measurements by the processing module may further comprise obtaining a differential value between the measurements and comparing the differential value to a threshold.
  • Determining by the processing module that the pressure field is applied may further comprise processing the measurements using a model of acoustic wave propagation within the structure stored in a memory module of the apparatus.
  • the model may comprise propagation speed of the plurality of acoustic waves within the structure.
  • the model may be based on a theoretical model or experimental results.
  • the apparatus may also comprise a plurality of wave generators and a plurality of wave sensors. Each wave generator and each wave sensor may be at known coordinates on the structure.
  • the processing module may further determine the model by processing the measurements and storing the model in the memory module.
  • the processing module further may determine the model by performing a free- calibration while the structure is free of external pressure.
  • the processing module may further provide the model by performing a loaded-calibration while an object of known characteristics is placed at a known location on the structure.
  • the processing module may further provide a model and determine that the pressure field is applied to the structure at a location on the surface by processing the plurality of measurements from different wave sensors from the plurality of wave sensors.
  • the processing module may further provide a model comprising at least propagation speed of the plurality of acoustic waves within the structure and determine that the pressure field is applied to the structure at a location on the surface by processing the plurality of measurements from different wave sensors from the plurality of wave sensors.
  • the model is either based on a theoretical approach or on experimental results.
  • the processing module may further determine an amplitude of the pressure field at the location on the surface by processing the measurements from the different wave sensors.
  • the processing module may correlate the measurements against the model retrieved from memory and provide a mapping of the pressure field on the surface of the structure from the correlated measurements.
  • the processing module may determine that at least one object applies the pressure field on the structure.
  • the object that applies the pressure field on the structure may be at more than one determined locations, the pressure field being of an associated number of determined amplitudes.
  • the object may be one or more fingers and the determined locations and determined amplitudes allow for fingerprint determination.
  • the location may be determined by the processing module within a predictable location tolerancing and the amplitude is determined within a predictable amplitude tolerancing.
  • the processing module may further approximate, from the determination, a position of the at least one object in three dimensions.
  • the processing module may further obtain a series of determinations over time.
  • the series of determinations may be used as an input to an electronic device.
  • the processing module may further determine that at least one animal applies the pressure field on the structure and use the series of determinations to evaluate behaviors of the animal.
  • the animal may be a mammal such as a rodent or a human.
  • Figure 1 is a schematic diagram representing exemplary interactions of acoustic waves in the presence of a local pressure field, in accordance with the teachings of the present invention
  • Figures 2A and 2B present graphs illustrating an evolution of the phase velocity for AO mode (2A) and SO mode (2B) in a surface under a pressure, in accordance with the teachings of the present invention
  • Figure 3 is a graph illustrating an evolution of a reflection coefficients in an exemplary 0.25 mm thick polycarbonate structure associated with SO mode at 100 kHz with respect to the local pressure for different lengths of application ⁇ , in accordance with the teachings of the present invention
  • Figure 4 is a visual representation of an exemplary prototype used for development in accordance with the teachings of the present invention.
  • Figure 5 is an exemplary imaging result obtained from the exemplary prototype using a 1 kg mass over a 6mm x 6mm area in accordance with the teachings of the present invention
  • Figure 6 is a perspective view of an exemplary apparatus in accordance with the teachings of the present invention.
  • Figure 7 is a modular representation of an exemplary controller unit in accordance with the teachings of the present invention.
  • Figure 8 is a flow chart of an exemplary method for determining that a pressure field is applied on a structure in accordance with the teachings of the present invention.
  • the present invention proposes a method and an apparatus for determining that a pressure field is applied on a structure.
  • the method and apparatus may also be used for determining the position and the strength of the pressure field applied to the structure.
  • a plurality of acoustic waves are generated within the structure using at least one wave generator and a plurality of measurements of the plurality of acoustic waves is taken using at least one wave sensor.
  • a pressure field applied to a surface of the structure is determined by processing at least two of the plurality of measurements. It is thought that the measurements correspond to reflections and echoes of the acoustic waves within the structure, as affected by a given pressure or pressure field. As such, the acoustic waves are scattered due, for instance, to the presence of the pressure field.
  • the wave generator and the wave sensor may, for instance, be piezoelectric elements.
  • the piezoelectric elements may alternate between acting as the wave generator and acting as the wave sensor.
  • Other examples of wave generators and wave sensors include ultrasonic wedges and air-coupled ultrasonic transducers.
  • the structure may be a thin structure made of rigid or flexible material, planar or curved and may allow the acoustic wave to be propagated therein.
  • the acoustic waves may be propagated as guided waves.
  • Processing the measurements may further comprise obtaining a differential value between the measurements and comparing the differential value to a threshold.
  • Determining that the pressure field is applied may further comprise processing the measurements using a model of acoustic wave propagation within the structure.
  • the model may, for instance, comprise propagation speed of the plurality of acoustic waves within the structure.
  • the model may be determined by processing the measurements before storing the model in a memory.
  • the model may be determined by performing a free-calibration while the structure is free of external pressure and/or by performing a loaded-calibration while an object of known characteristics is placed at a known location on the structure.
  • the model may be based on theoretical or empirical approaches.
  • a model may determine that the pressure field is applied to the structure at a location on the surface by processing the measurements from different wave sensors.
  • An amplitude of the pressure field at the location on the surface may further be determined by processing the measurements of the scattered wave due to the local pressure field.
  • correlating the measurements with the model retrieved from memory may further be performed in order to provide a mapping of the pressure field on the surface of the structure.
  • a model comprising at least propagation speed of the plurality of acoustic waves within the structure may be providing and it may determine that the pressure field is applied to the structure at a location on the surface by processing the measurements from different wave sensors.
  • An amplitude of the pressure field at the location on the surface may further be determined by processing the measurements from the different wave sensors.
  • correlating the measurements against the model retrieved from memory may further be performed in order to provide a mapping of the pressure field on the surface of the structure.
  • At least one object applies the pressure field on the structure. It may further be determined that the object applies the pressure field on the structure at more than one determined locations with an associated number of determined amplitudes.
  • the object may be one or more finger and the determined locations and determined amplitudes may allow for fingerprint determination.
  • the location may be determined within a predictable location tolerancing and the amplitude is determined within a predictable amplitude tolerancing. From the determination, a position of the at least one object in three dimension may be approximately provided.
  • a series of determinations may be obtained over time.
  • the series of determinations may be used as an input to an electronic device. It may also be determined that at least one animal applies the pressure field on the structure. The series of determinations may then be used to evaluate animal behavior.
  • the animal may be a mammal such as a rodent or a human.
  • the present invention relates to a method and an apparatus that can be used for determining the spatiotemporal distribution of at least one pressure level applied on a surface of a structure.
  • some structures allow for acoustic waves to be propagated therein.
  • the acoustic waves will be propagated as guided waves.
  • thin structures usually allow for ultrasonic acoustic waves to be propagated as guided waves. Reflection and dispersion of the guided waves can then be modeled within the structure. It has been determined that a pressure field applied to the modeled structure at one or more specific locations predictably affect the reflection and dispersion of the acoustic waves.
  • FIG. 1 shows a schematic diagram representing exemplary interactions of acoustic waves (I) in the presence of a local pressure field (P), in accordance with the teachings of the present invention.
  • I acoustic waves
  • P local pressure field
  • Another effect of local added object is that part of the energy appears to be transmitted into the object, responsible for a loss of transmitted energy. This effect can be observed when a perfect contact is ensured between the host structure and the added object and when the acoustic impedances of both structures are similar.
  • the sensed object is expected to be a tissue with associated low acoustic impedance compared to metallic or polymer structures. Thus, in the context of the present invention, it appears that this effect can be neglected when considering the interaction of an acoustic wave with a local added mass.
  • an added mass M applied at the surface of a thin structure appears to create a local change of surface stress, such that the propagation of acoustic waves, and especially guided waves (for instance AO and SO modes), is locally modified.
  • the added mass M applied over a surface S can be described as a local change of boundary stresses (equations are not necessary since it is an approximation).
  • Figure 3 represents the evolution of the reflection coefficient associated with SO mode at 100 kHz with respect to the added pressure for a 0.25 mm thick polycarbonate structure for various pressure application lengths.
  • the reflection of SO mode is total (reflection coefficient of 1), defining a range of detectable pressure levels.
  • Those minimal and maximal pressure values define the pressure sensitivity range, depending on the desired application and are related to the material properties and thickness only.
  • Pressure sensitivity A given application likely provides a requirement of sensitivity within a given range of pressure. Thus, minimal and maximal pressures are to be defined. It appears that those parameters are related to the material thickness and properties (Young's modulus, density and Poisson's ratio). In the case of touch screen applications, for instance, pressure levels from 10 to 10 000 Pa have been identified, such that thin structures (below 1mm) with Young's modulus above 5GPa can be employed.
  • Imaging precision According to the research conducted, the mode and frequency of an acoustic wave will determine if imaging of the pressure field is possible. Indeed, the frequency and mode selection determines the wavelength ⁇ of the generated wave. The imaging precision is related to this wavelength and imaging spot surfaces are of the order of ⁇ 2 . For touch screen application, for instance, a wavelength of approximately 5mm could be used. The choice of mode, frequency and piezoceramic size are derived from this value after selecting the material properties. Moreover, the precision of imaging contour is related to the number of wave generators and sensors used in the application. The precision of imaging contour may also be related to the number of units and the quality of the signal processing algorithm.
  • SNR Signal to noise ratio
  • the number N of transducer units, the sampling rate Fs and size of grid for imaging are determined by the limitations of the processing unit. For portable application (FPGA integration, for instance), 8 units processed at 10 MHz can be used for imaging over a grid of 100x100 pixels. [0061] In the course of the research work performed, an exemplary prototype has been developed for determination of pressure field for touch screen application over a large surface. The sensitive part is composed of the 0.25 mm thick stainless steel plate.
  • the plate dimensions are 500 x 500 mm and it is instrumented with 8 piezoceramics (4 actuators and 4 sensors) of 10 mm diameter and 0.25 mm thickness located at the periphery.
  • an absorbing layer viscoelastic tape
  • Figure 4 is a visual representation of an exemplary prototype used for development in accordance with the teachings of the present invention.
  • the signal generation, acquisition and processing can be performed by a dedicated platform (Nl PXI 7962) and analysis is performed using Matlab application.
  • a dedicated platform Nl PXI 7962
  • FPGA Field Programmable Gate Arrays
  • Figure 5 shows an exemplary imaging result obtained from the exemplary prototype of Figure 4 using a 1 kg mass over a 6mm x 6mm area.
  • generating the waves in the structure was best achieved by using a piezoelectric element, acting as a generator, at the periphery of the structure of interest.
  • a plurality of piezoelectric elements acting as piezoelectric sensors, then measure the response of the structure to the waves. It has also been determined that by using a plurality of piezoelectric elements, they could be used, in turn, as the wave generator and piezoelectric sensors.
  • the piezoelectric elements (or piezoelectric ceramics) may be permanently fixed to the structure (e.g., glued or eventually built in). The response of the structure to the waves is collected as a plurality of signals.
  • the signals correspond to reflections and echoes of the waves within the structure, as affected by a given pressure or pressure field.
  • an important exemplary advantage with regard to the industrial applicability of the solution is that the plurality of signals collected allow to predictably represent location and amplitude of at least one pressure applied to the structure.
  • EUSR Embedded Ultrasonic Structural Radar
  • Excitelet as mentioned in the referenced document
  • FIG. 6 shows a perspective view of an exemplary apparatus 100 in accordance with the teachings of the present invention.
  • a structure 110 is provided with a plurality of transducers 132-146 thereon.
  • the transducer 140 is illustrated in a different shade to illustrate that it functions as an ultrasonic wave generator while the other transducers 132-138, 142-146 function as wave sensors.
  • the transducers are shown connected to an exemplary data bus 150, which connects the transducers to a controller unit 120. Skilled person will understand that only one generator is shown, but that a plurality of generators may be used in order to increase precision to a desired level. Still in order to increase precision, the transducers 132-146 may exchange their role as generator and sensors.
  • the wave pattern changes and can be measured by the transducers 132-146 then acting as wave sensors.
  • the measurements can be passed on to the controller unit 120 where it can be processed to identify a position in the plane and to determine pressure data with respect to the measurements. For additional precision, processing may be improved with the use of three or more sensors.
  • Mapping tools such Embedded Ultrasonic Structural Radar (EUSR) and/or
  • Excitelet may then be used to establish a spatial mapping of locations and amplitudes of the applied pressure. Interpretation of the results obtained by these imaging algorithms is enhanced by knowledge of the mechanical properties of the structure 110. Calibration may be required in order to precisely identify the properties and material of the structure 1 0 may need to be changed to achieve desired results.
  • FIG. 7 shows a modular representation of the exemplary controller unit 120 in accordance with the teachings of the present invention.
  • the controller unit 120 comprises a data acquisition module 210 for obtaining the measurements from the transducers 132- 138, 140-146 and a wave generation module for controlling the transducer 140.
  • the wave generation module 220 may further use more than one of the transducers 132-146 as wave sensors and/or more than one of the transducers 132-146 as wave generators).
  • the wave generation module 220 may further control the transducers 132-146 so that they exchange their role as generator and sensors (e.g. please provide range of frequency).
  • an electrical signal pulse having a center frequency e.g., typically in the order of several hundred kilohertz as a burst
  • a center frequency e.g., typically in the order of several hundred kilohertz as a burst
  • Generated waves are attenuated differently in different materials.
  • Viscoelastic material e.g. elastomers
  • the transducers 132-146 may be distributed over the structure 110 or its periphery (sparse array) or condensed in order to achieve an antenna (compact array).
  • an imaging tool can be used (such Embedded Ultrasonic Structural Radar (EUSR) or Excitelet).
  • EUSR is based on the estimate of the position of a reflector using time data spread (Time-of- Flight), which ignores the dispersive nature of waves propagating. The result is a rapid but imprecise determination.
  • Excitelet is based on the correlation of measured reflections with synthetic signals from the theoretical propagation or experimental measurements (e.g. model) of the waves. The Excitelet can detect defects in thin structures and it appears advantageous to use this approach in this case, at least for applications requiring higher precision.
  • a mix of both techniques may also be used (e.g., depending on an application running on an electronic product which has the structure 110 as an input device). For instance, in tests performed in a research context with two identical objects, EUSR shows the extent of pressure areas but the relative intensity of each differs while Excitelet shows the two pressure zones with the same intensity (with less than 10% error). [0078] In the context of the research performed, it appears that the size of the area to be inspected is limited by the spread of waves. Indeed, any material has a coefficient representing the rate viscoelastic damping mechanical waves therein. Also, the material and the frequencies of waves generated should be chosen carefully in view of the desired application to ensure that the echo can be spread without limitation, other than the deformation, to the sensors.
  • the expected sizes for this type of application can range from a few centimeters (e.g., graphic palettes) to more than one meter (e.g., medical and oversized touch screen).
  • the material should then have a strong resistance to external shocks. This is characterized by a large yield (of the order of several hundreds of MPa).
  • the quality of the results obtained by the imaging algorithms is improved by knowledge of mechanical properties of the propagation.
  • the accuracy of the pressure mapping depends on the imaging algorithm implemented and the desired response time.
  • FPGA Field Programmable Gate Arrays
  • the use of Field Programmable Gate Arrays (FPGA) have allowed using the Excitelet algorithm with a 100 x 100 grid and achieve 25 frames per second.
  • FPGA Field Programmable Gate Arrays
  • processing is performed by a high-speed FPGA in coordination with LabVIEW.
  • the imaging algorithm e.g., EUSR, Excitelet, etc.
  • an electronic signal conditioning has also been developed to adapt the impedance of the sensor and pre-amplify the signals. It is expected that dedicated solutions will keep improving on those results and provide diverse real-time ranges of sensitivity and size.
  • Figure 8 shows a flow chart of an exemplary method for determining that a pressure field is applied on a structure in accordance with the teachings of the present invention.
  • the method comprises generating a plurality of acoustic waves within the structure using at least one wave generator 810 and taking a plurality of measurements of the plurality of acoustic waves using at least one wave sensor 820.
  • the method also comprises determining that a pressure field is applied to a surface of the structure by processing the plurality of measurements 830.
  • the acoustic waves are scattered due, for instance, to the presence of the pressure field.
  • the wave generator and the wave sensor may, for instance, be piezoelectric elements.
  • the piezoelectric elements may alternate between acting as the wave generator and acting as the wave sensor.
  • a processor module may represent a single processor with one or more processor cores or an array of processors, each comprising one or more processor cores.
  • a memory module may comprise various types of memory (different standardized or kinds of Random Access Memory (RAM) modules, memory cards, Read-Only Memory (ROM) modules, programmable ROM, etc.).
  • a storage devices module may represent one or more logical or physical as well as local or remote hard disk drive (HDD) (or an array thereof).
  • the storage devices module may further represent a local or remote database made accessible to a network node by a standardized or proprietary interface.
  • a network interface module represents at least one physical interface that can be used to communicate with other network nodes. For the sake of simplicity, the following example related to the network node will refer to a repository to represent the various means that can be used to store records.
  • the network interface module may be made visible to the other modules of the network node through one or more logical interfaces. The actual stacks of protocols used by the physical network interface(s) and/or logical network interface(s) of the network interface module do not affect the teachings of the present invention.
  • processor module memory module
  • network interface module storage devices module
  • storage devices module usable in the context of the present invention
  • a method is generally conceived to be a self-consistent sequence of steps leading to a desired result. These steps require physical manipulations of physical quantities. Usually, though not necessarily, these quantities take the form of electrical or magnetic signals capable of being stored, transferred, combined, compared, and otherwise manipulated. It is convenient at times, principally for reasons of common usage, to refer to these signals as bits, values, parameters, items, elements, objects, symbols, characters, terms, numbers, or the like. It should be noted, however, that all of these terms and similar terms are to be associated with the appropriate physical quantities and are merely convenient labels applied to these quantities. The description of the present invention has been presented for purposes of illustration but is not intended to be exhaustive or limited to the disclosed embodiments.

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  • Engineering & Computer Science (AREA)
  • General Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • General Engineering & Computer Science (AREA)
  • Theoretical Computer Science (AREA)
  • Human Computer Interaction (AREA)
  • Health & Medical Sciences (AREA)
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  • Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)

Abstract

La présente invention concerne un procédé et un appareil permettant de déterminer qu'un champ de pression est appliqué sur une structure. Une pluralité d'ondes acoustiques est générée à l'intérieur de la structure, à l'aide d'au moins un générateur d'ondes et une pluralité de mesures des ondes acoustiques est prise à l'aide d'au moins un capteur d'onde. Un champ de pression, appliqué à une surface de la structure, est déterminé par traitement d'au moins deux des mesures parmi la pluralité de mesures. Le générateur d'ondes et le capteur d'ondes peuvent être des éléments piézoélectriques, qui peuvent agir en alternance en tant que générateur d'ondes et en tant que capteur d'ondes. Le traitement des mesures peut comprendre l'obtention d'une valeur de mesure différentielle et la comparaison de la valeur à un seuil. La détermination du fait que le champ de pression est appliqué peut comprendre le traitement des mesures à l'aide d'un modèle basé sur la propagation d'ondes acoustiques ou sur des résultats d'expérimentations. Ce traitement peut permettre d'obtenir une mise en concordance du champ de pression d'un objet sur la structure.
PCT/CA2013/000688 2010-03-05 2013-08-01 Système de mise en concordance de pression acoustique active WO2014019075A1 (fr)

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CA2920406A CA2920406C (fr) 2012-08-03 2013-08-01 Systeme de mise en concordance de pression acoustique active
US14/419,257 US9750451B2 (en) 2010-03-05 2013-08-01 Active acoustic pressure mapping system

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US201261679232P 2012-08-03 2012-08-03
US61/679,232 2012-08-03

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA2175691A1 (fr) * 1993-11-04 1995-05-11 John K. Schneider Appareil et procede d'imagerie par ultrasons a haute resolution
WO1998007127A1 (fr) * 1996-08-12 1998-02-19 Elo Touchsystems, Inc. Capteur a condition acoustique mettant en oeuvre une pluralite d'ondes non orthogonales entre elles
CA2604969A1 (fr) * 2005-04-20 2006-10-26 Vivometrics, Inc. Systemes et procedes de mesure physiologique non invasive d'animaux non humains
CA2611681A1 (fr) * 2005-06-10 2007-03-29 Qsi Corporation Dispositif d'entree base sur la force

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA2175691A1 (fr) * 1993-11-04 1995-05-11 John K. Schneider Appareil et procede d'imagerie par ultrasons a haute resolution
WO1998007127A1 (fr) * 1996-08-12 1998-02-19 Elo Touchsystems, Inc. Capteur a condition acoustique mettant en oeuvre une pluralite d'ondes non orthogonales entre elles
CA2604969A1 (fr) * 2005-04-20 2006-10-26 Vivometrics, Inc. Systemes et procedes de mesure physiologique non invasive d'animaux non humains
CA2611681A1 (fr) * 2005-06-10 2007-03-29 Qsi Corporation Dispositif d'entree base sur la force

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