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WO1991005220A1 - Acoustic holographic array measurement device and related method - Google Patents

Acoustic holographic array measurement device and related method Download PDF

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Publication number
WO1991005220A1
WO1991005220A1 PCT/US1990/005436 US9005436W WO9105220A1 WO 1991005220 A1 WO1991005220 A1 WO 1991005220A1 US 9005436 W US9005436 W US 9005436W WO 9105220 A1 WO9105220 A1 WO 9105220A1
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WIPO (PCT)
Prior art keywords
phase data
shape
acoustic waves
transmitter
transmitting
Prior art date
Legal status (The legal status 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 status listed.)
Ceased
Application number
PCT/US1990/005436
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French (fr)
Inventor
Michael A. Reed
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
ENVIRONMENTAL PRODUCTS CORP
Original Assignee
ENVIRONMENTAL PRODUCTS CORP
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.)
Filing date
Publication date
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Publication of WO1991005220A1 publication Critical patent/WO1991005220A1/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B07SEPARATING SOLIDS FROM SOLIDS; SORTING
    • B07CPOSTAL SORTING; SORTING INDIVIDUAL ARTICLES, OR BULK MATERIAL FIT TO BE SORTED PIECE-MEAL, e.g. BY PICKING
    • B07C5/00Sorting according to a characteristic or feature of the articles or material being sorted, e.g. by control effected by devices which detect or measure such characteristic or feature; Sorting by manually actuated devices, e.g. switches
    • B07C5/04Sorting according to size
    • B07C5/12Sorting according to size characterised by the application to particular articles, not otherwise provided for
    • B07C5/122Sorting according to size characterised by the application to particular articles, not otherwise provided for for bottles, ampoules, jars and other glassware
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01BMEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B17/00Measuring arrangements characterised by the use of infrasonic, sonic or ultrasonic vibrations
    • G01B17/06Measuring arrangements characterised by the use of infrasonic, sonic or ultrasonic vibrations for measuring contours or curvatures

Definitions

  • the invention relates generally to an acoustic holographic array, and specifically to an acoustic device fo measuring the shape of an object.
  • Known systems for forming acoustic discriminator hologram patterns typically include an acoustic transmitter for transmitting acoustic waves at an object to be examined, and an acoustic receiver transducer for detecting acoustic signals from the transmitter which have passed by or through the object or have been defracted or reflected therefrom, th acoustic receiver transducer scanning over a desired area of the object.
  • a sampler takes substantially instantaneous samples of the amplitude of the signals received from the acoustic receiver transducer at predetermined time intervals.
  • Such systems are complicated in construction and require tha the acoustic receiver transducer repeatedly scan the object to be measured to produce useful data concerning the shape o the object.
  • Other systems for measuring the shape of an object include a light source which transmits light toward the object to be measured.
  • a photoelectric sensing unit is positioned behind the object and detects the shadow image of the object and the transition between and light and shadow caused by the boundary of the object.
  • the photoelectric sensing unit detects the amplitude of the light transmitted from the light source through the object and thus can be used to identify characteristics of the shape of the object.
  • such systems suffer from the disadvantage that the identified characteristics of the edges of the objects may be distorted due to the shape and composition of the objects. Thus, the accuracy of such systems is reduced.
  • the invention comprises a device and related method for measuring the shape of an object, the device including a plurality of transmitters for transmitting acoustic waves at the object, a plurality of receivers for receiving the acoustic waves reflected by the object, a total phase detector for measuring the total phase data of the received acoustic waves, a processor for calculating a value representing the shape of the object as function of the total phase data and means for comparing the value with predetermined reference values to identify the shape of the object.
  • FIG. 1 is a side view of a preferred embodiment of a measuring device embodying the teachings of the present invention
  • Fig. la is an isometric view of an acoustic radiation transmission pattern from the transmitting transducer illustrated in Fig. 1;
  • Fig. 2 is a top view of the device illustrated in Fig. i;
  • Fig. 3a is a plot illustrating the output of the devic illustrated in Fig. 1;
  • Fig. 3b is a second plot illustrating an output of the device illustrated in Fig. 1;
  • Fig. 3c is a third plot illustrating another output of the device illustrated in Fig. 1;
  • Fig. 3d is a fourth plot illustrating another output of the device illustrated in Fig. 1;
  • Fig. 3e is a fifth plot illustrating another output of the device illustrated in Fig. 1;
  • Fig. 3f is a sixth plot illustrating another output of the device illustrated in Fig. 1;
  • Fig. 3g is a seventh plot illustrating another output of the device illustrated in Fig. 1.
  • the present invention utilizes holographic concepts with ultrasonic sound waves.
  • the concept is based on the reflection and scattering of sound waves from an object to be measured or imaged.
  • the total phase of the sound waves is calculated by measuring the time necessary for the front of sound waves to travel from a transmitter, reflect from the object and return to a receiver in whole wavelengths plus a fraction of one wavelength of the transmitted signal in the medium of propagation.
  • phase data hereafter refers to either the total phase or the fractional component of the total phase.
  • the amplitude and total phase of the scattered waves may be measured over a plane (for two-dimensional analysis) or a line (for one-dimensional analysis).
  • the resulting total phase and amplitude array is used to reconstruct the shape of the original object, subject only to sampling limitations on the phase data.
  • the basic spatial characteristics of the object to be measured are preserved when the array of phase data is calculated.
  • the use of only phase data reduces the amount of memory necessary to store amplitude data and further reduces the processing time necessary to process the phase data.
  • the subject invention processes the phase data to generate values unique to the shape of the object to be measured. As a result, the physical shape of the object is converted to a series of phase related values unique to that shape.
  • Fig. 1 is a side view of a system showing major components of a preferred embodiment of a measuring device embodying the teachings of the present invention.
  • the system comprises a transmitter/receiver array 20.
  • Array 20 includes a plurality of pairs of individual transmitters and corresponding receivers for transmitting acoustic waves to and receiving acoustic waves from the object to be measured, such as a container 40.
  • array 20 comprises seven pairs of vertically oriented fan beam ultrasonic transmitting transducers 21-27 and corresponding omnidirectional pressure sensitive broadband microphone receivers 31-37 arranged in a vertical array so that the acoustic waves transmitted from transmitters 21-27 overlap in the vertical direction.
  • Fig. la illustrates a preferred vertical radiation pattern 60 and a preferred horizontal radiation pattern 62.
  • the spacing between each of transmitters 21-27 and corresponding receivers 31-37 may be predetermined depending on the size of the object to be measured. For example, if container 40 is a common twelve ounce beverage container, transmitters 21, 22, 23, 24, 25, 26, 27 and receivers 31, 32, 33, 34, 35, 36, 37 are preferably spaced approximately two inches apart.
  • Fig. 2 The system of the subject invention is further illustrated in Fig. 2.
  • an object to be measured such as a container 40
  • Transmitter 21 of transmitter/receiver array 20 transmits a high frequency ultrasonic signal toward container 40.
  • the signal has a frequency of approximately 50 kHz and a wavelength of approximately 0.27 inches.
  • the signal is reflected by container 40 and received by receivers 31-37 in array 20.
  • Each receiver 31-37 measures the phase of the reflected signal.
  • Receivers 31-37 therefore comprise phase detector means for measuring the signals reflected by container 40.
  • the signal from each of receivers 31-37 is passed to a signal processor (not shown) which processes the data and extracts the phase data of the received signal for each path of reflection from transmitter 21 to container 40 and back to each of receivers 31-37 and stores the phase data of each received signal which is unique to the shape of container 40 as compared to a reference shape.
  • the sequence of transmission by one transmitter, such as transmitter 21, and reception by each of the receivers 31-37 is repeated for each of transmitters 22- 27.
  • the resulting phase data forms a data array seven by seven in size generated by each pair of transmitters and receivers.
  • the diagonal of the data array represents the transmission reflection path from each transmitter 21-27 to its corresponding receiver 31-37, respectively.
  • the data array as a whole contains phase data unique to container 40 which may be processed by the signal processor to measure the shape of container 40.
  • the signal processor can perform a square root of the sum of the squares comparison of the differences in the phase data to generate values representing the shape of container 40, as compared to stored phase data, phase data of a reference shape, phase data of other containers in a test or phase data of a zero reference shape. Results of this processing are illustrated in Figs. 3a-3g.
  • Figs. 3a-3g illustrate a series of measurements that have been performed by a second preferred embodiment of the subjects invention which transmits acoustic waves having a frequency of 20 kHz and illustrate the accuracy of the device and method of the claimed invention.
  • the shapes of seven distinctly shaped containers 40 were measured individually using phase data generated by one transmitter and four receivers and compared with each other and a zero reference shape to identify each container.
  • the Y-axis represents square root of the sum of the squares of the difference between the phase data generated for each container 40 as compared to the phase data of each other container measured and the zero reference shape.
  • a value of 0.00 represents a perfect match between the shapes of the respective containers, while higher values represent increased distinctness between the shapes of the containers.
  • Fig. 3a compares the phase data of the seven beer bottles against a known reference shape, in this case the shape of a Tuborg bottle which is double underlined. As illustrated in Fig. 3a, the shape of the Tuborg bottle is readily identified, as illustrated by the minimum least squares value of almost 0. The other bottles, which differ in shape from the Tuborg bottle, all reflect values substantially higher than 0.
  • Figs. 3b-3g illustrate results similar to those illustrated in Fig. 3a.
  • the system of the subject invention accurately identifies the shape of one of the sample beer bottles as that of the reference bottle. Even when two of the bottles are substantially identical in shape, as in the case of the Becks beer bottle and the St. Pauli Girl beer bottle, the system of the subject invention differentiates between the shapes of the two bottles using phase data received from only four receivers. The results of the specific measurements of the shapes of these two bottles are illustrated in Figs. 3d and 3g.
  • the subject invention provides a simple, economical, and accurate way for measuring the shape of an unknown object.
  • Other embodiments of the invention such as using more or less than the preferred seven transmitter and receiver pairs or using unequal numbers of transmitters and receivers which may not be located together in pairs, will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. Items intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Length Measuring Devices Characterised By Use Of Acoustic Means (AREA)
  • Measurement Of Velocity Or Position Using Acoustic Or Ultrasonic Waves (AREA)

Abstract

An acoustic device and related method for measuring the shape of an object. The device includes a plurality of transmitters for transmitting acoustic waves at an object to be measured and a plurality receivers for receiving the acoustic waves reflected by the object. A phase detector measures phase data of the reflected acoustic waves, the phase data being processed to calculate a value representing a shape of the object as a function of the phase data. This value is then compared with known reference value to accurately identify the shape of the object.

Description

Description ACOUSTIC HOLOGRAPHIC ARRAY MEASUREMENT DEVICE AND RELATED METHOD Technical Field
The invention relates generally to an acoustic holographic array, and specifically to an acoustic device fo measuring the shape of an object. Background Art
Known systems for forming acoustic discriminator hologram patterns typically include an acoustic transmitter for transmitting acoustic waves at an object to be examined, and an acoustic receiver transducer for detecting acoustic signals from the transmitter which have passed by or through the object or have been defracted or reflected therefrom, th acoustic receiver transducer scanning over a desired area of the object. A sampler takes substantially instantaneous samples of the amplitude of the signals received from the acoustic receiver transducer at predetermined time intervals. Such systems are complicated in construction and require tha the acoustic receiver transducer repeatedly scan the object to be measured to produce useful data concerning the shape o the object.
Other systems for measuring the shape of an object include a light source which transmits light toward the object to be measured. A photoelectric sensing unit is positioned behind the object and detects the shadow image of the object and the transition between and light and shadow caused by the boundary of the object. The photoelectric sensing unit detects the amplitude of the light transmitted from the light source through the object and thus can be used to identify characteristics of the shape of the object. However, such systems suffer from the disadvantage that the identified characteristics of the edges of the objects may be distorted due to the shape and composition of the objects. Thus, the accuracy of such systems is reduced.
SUBSTITUTE SHEET Disclosure of the Invention
Accordingly, it is an object of the present invention to provide a device and related method for measuring the shape of an object which is simple in construction and accurate in performance.
It is a further object of the present invention to provide a device and related method which provide a fast and efficient method of classification and recognition of the shape of an object, while avoiding excessive memory requirements.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims.
To achieve the objects and in accordance with the purpose of the invention as embodied and broadly described herein, the invention comprises a device and related method for measuring the shape of an object, the device including a plurality of transmitters for transmitting acoustic waves at the object, a plurality of receivers for receiving the acoustic waves reflected by the object, a total phase detector for measuring the total phase data of the received acoustic waves, a processor for calculating a value representing the shape of the object as function of the total phase data and means for comparing the value with predetermined reference values to identify the shape of the object.
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate one embodiment of the invention and together with the description, serve to explain the principles of the invention.
SUBSTITUTE SHEET Brief Description of the Drawings Fig. 1 is a side view of a preferred embodiment of a measuring device embodying the teachings of the present invention;
Fig. la is an isometric view of an acoustic radiation transmission pattern from the transmitting transducer illustrated in Fig. 1;
Fig. 2 is a top view of the device illustrated in Fig. i;
Fig. 3a is a plot illustrating the output of the devic illustrated in Fig. 1;
Fig. 3b is a second plot illustrating an output of the device illustrated in Fig. 1;
Fig. 3c is a third plot illustrating another output of the device illustrated in Fig. 1;
Fig. 3d is a fourth plot illustrating another output of the device illustrated in Fig. 1;
Fig. 3e is a fifth plot illustrating another output of the device illustrated in Fig. 1;
Fig. 3f is a sixth plot illustrating another output of the device illustrated in Fig. 1; and
Fig. 3g is a seventh plot illustrating another output of the device illustrated in Fig. 1.
Best Mode for Carrying Out the Invention
Reference will now be made in detail to the present preferred embodiment and method of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible the same reference numbers will be used throughout the drawings- to refer to same or like parts.
The present invention utilizes holographic concepts with ultrasonic sound waves. The concept is based on the reflection and scattering of sound waves from an object to be measured or imaged. The total phase of the sound waves is calculated by measuring the time necessary for the front of sound waves to travel from a transmitter, reflect from the object and return to a receiver in whole wavelengths plus a fraction of one wavelength of the transmitted signal in the medium of propagation. The term phase data hereafter refers to either the total phase or the fractional component of the total phase. The amplitude and total phase of the scattered waves may be measured over a plane (for two-dimensional analysis) or a line (for one-dimensional analysis). The resulting total phase and amplitude array is used to reconstruct the shape of the original object, subject only to sampling limitations on the phase data.
The basic spatial characteristics of the object to be measured are preserved when the array of phase data is calculated. The use of only phase data reduces the amount of memory necessary to store amplitude data and further reduces the processing time necessary to process the phase data. The subject invention processes the phase data to generate values unique to the shape of the object to be measured. As a result, the physical shape of the object is converted to a series of phase related values unique to that shape.
Fig. 1 is a side view of a system showing major components of a preferred embodiment of a measuring device embodying the teachings of the present invention. As shown in Fig. 1, the system comprises a transmitter/receiver array 20. Array 20 includes a plurality of pairs of individual transmitters and corresponding receivers for transmitting acoustic waves to and receiving acoustic waves from the object to be measured, such as a container 40. In a presently preferred embodiment of the present invention, array 20 comprises seven pairs of vertically oriented fan beam ultrasonic transmitting transducers 21-27 and corresponding omnidirectional pressure sensitive broadband microphone receivers 31-37 arranged in a vertical array so that the acoustic waves transmitted from transmitters 21-27 overlap in the vertical direction. Such a preferred radiation pattern is illustrated in Fig. la which illustrates a preferred vertical radiation pattern 60 and a preferred horizontal radiation pattern 62. The spacing between each of transmitters 21-27 and corresponding receivers 31-37 may be predetermined depending on the size of the object to be measured. For example, if container 40 is a common twelve ounce beverage container, transmitters 21, 22, 23, 24, 25, 26, 27 and receivers 31, 32, 33, 34, 35, 36, 37 are preferably spaced approximately two inches apart.
The system of the subject invention is further illustrated in Fig. 2. As shown in Fig. 2, an object to be measured, such as a container 40, is provided in a U-shaped trough 42. Transmitter 21 of transmitter/receiver array 20 transmits a high frequency ultrasonic signal toward container 40. Preferably, the signal has a frequency of approximately 50 kHz and a wavelength of approximately 0.27 inches. The signal is reflected by container 40 and received by receivers 31-37 in array 20. Each receiver 31-37 measures the phase of the reflected signal. Receivers 31-37 therefore comprise phase detector means for measuring the signals reflected by container 40. The signal from each of receivers 31-37 is passed to a signal processor (not shown) which processes the data and extracts the phase data of the received signal for each path of reflection from transmitter 21 to container 40 and back to each of receivers 31-37 and stores the phase data of each received signal which is unique to the shape of container 40 as compared to a reference shape. In a preferred embodiment, the sequence of transmission by one transmitter, such as transmitter 21, and reception by each of the receivers 31-37 is repeated for each of transmitters 22- 27. The resulting phase data forms a data array seven by seven in size generated by each pair of transmitters and receivers. The diagonal of the data array represents the transmission reflection path from each transmitter 21-27 to its corresponding receiver 31-37, respectively. The data array as a whole contains phase data unique to container 40 which may be processed by the signal processor to measure the shape of container 40. For example, the signal processor can perform a square root of the sum of the squares comparison of the differences in the phase data to generate values representing the shape of container 40, as compared to stored phase data, phase data of a reference shape, phase data of other containers in a test or phase data of a zero reference shape. Results of this processing are illustrated in Figs. 3a-3g.
Figs. 3a-3g illustrate a series of measurements that have been performed by a second preferred embodiment of the subjects invention which transmits acoustic waves having a frequency of 20 kHz and illustrate the accuracy of the device and method of the claimed invention. In the measurements, the shapes of seven distinctly shaped containers 40 were measured individually using phase data generated by one transmitter and four receivers and compared with each other and a zero reference shape to identify each container. In each of Figs 3a-3g, the Y-axis represents square root of the sum of the squares of the difference between the phase data generated for each container 40 as compared to the phase data of each other container measured and the zero reference shape. A value of 0.00 represents a perfect match between the shapes of the respective containers, while higher values represent increased distinctness between the shapes of the containers.
Fig. 3a compares the phase data of the seven beer bottles against a known reference shape, in this case the shape of a Tuborg bottle which is double underlined. As illustrated in Fig. 3a, the shape of the Tuborg bottle is readily identified, as illustrated by the minimum least squares value of almost 0. The other bottles, which differ in shape from the Tuborg bottle, all reflect values substantially higher than 0.
Figs. 3b-3g illustrate results similar to those illustrated in Fig. 3a. In each measurement, the system of the subject invention accurately identifies the shape of one of the sample beer bottles as that of the reference bottle. Even when two of the bottles are substantially identical in shape, as in the case of the Becks beer bottle and the St. Pauli Girl beer bottle, the system of the subject invention differentiates between the shapes of the two bottles using phase data received from only four receivers. The results of the specific measurements of the shapes of these two bottles are illustrated in Figs. 3d and 3g.
Thus, the subject invention provides a simple, economical, and accurate way for measuring the shape of an unknown object. Other embodiments of the invention, such as using more or less than the preferred seven transmitter and receiver pairs or using unequal numbers of transmitters and receivers which may not be located together in pairs, will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. Items intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.
SUBSTITUTE SHEET

Claims

Claims
1. An acoustic device for measuring the shade of an object comprising: transmitter means for transmitting acoustic waves at an object to be measured; receiver means for receiving said acoustic waves reflected by said object; measurement means for measuring phase data of said acoustic waves received by said receiver means; calculation means for calculating values representing the shape of said object as a function of said phase data; and means for comparing said values with predetermined reference values to identify the shape of said object.
2. A device according to claim 1, wherein said transmitter means includes a plurality of transmitting transducers.
3. A device according to claim 1, wherein said receiver means includes a plurality of microphone receivers.
4. A device according to claim 1, wherein said transmitter means radiates said acoustic waves in substantially a fan beam pattern.
5. A device according to claim 1, wherein said transmitter means and said receiver means comprise a plurality of transmitter and receiver pairs arranged in a one dimensional array.
6. A device according to claim 1, wherein said transmitter means and said receiver means comprise a plurality of transmitter and receiver pairs arranged in a two dimensional array.
7. A device according to claim 1, wherein said comparison means compares a representation of said phase data with a predetermined representation of a reference object to determine if said measured phase data represents said reference object.
SUBSTITUTESHEET
8. A device according to claim 1, wherein said comparison means compares phase data differences between sai measured phase data to stored phase data to identify the shape of said object.
9. A device according to claim 1, wherein said comparison means compares stored phase data to the square root of the sum of the squares of said phase data calculated by said calculation means to identify the shape of said object.
10. An acoustic method for measuring the shape of an object comprising the steps of: transmitting acoustic waves at an object to be measured; receiving said acoustic waves reflected by said object; measuring phase data of said acoustic waves reflected by said object; calculating values representing the shape of said object as a function of said phase data; comparing said values with predetermined reference values to identify the shape of said object.
11. A method according to claim 10, wherein said transmitting step transmits said acoustic waves' using a plurality of transmitting transducers.
12. A method according to claim 10, wherein said receiving step receives said acoustic waves using a plurality of microphone receivers.
13. A method according to claim 10, wherein said transmitting step radiates said acoustic waves in substantially a fan beam pattern.
14. A method according to claim 10, wherein said transmitting step and said receiving step transmit and receive said acoustic waves using a plurality of transmitter and receiver pairs arranged in a one dimensional array.
15. A method according to claim 10, wherein said transmitting step and said receiving step transmit and
SUBSTITUTESHEET receive said acoustic waves using a plurality of transmitter and receiver pairs arranged in a two dimensional array.
16. A method according to claim 10, wherein said comparison step compares a representation of said phase data with a predetermined representation of an reference object to determine if said measured phase data represents said reference object.
17. A method according to claim 10, wherein said comparison step compares phase data differences between said measured phase data to stored phase data to identify the shape of said object.
18. A method according to claim 10, wherein said comparison step compares stored phase data to the square root of the sum of the squares of said phase data calculated in said calculating step to identify the shape of said object.
SUBSTITUTE SHEET
PCT/US1990/005436 1989-09-28 1990-09-28 Acoustic holographic array measurement device and related method Ceased WO1991005220A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US41394189A 1989-09-28 1989-09-28
US413,941 1989-09-28

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5615778A (en) * 1991-07-29 1997-04-01 Rwe Entsorgung Aktiengesellschaft Process to sort waste mixtures

Citations (6)

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Publication number Priority date Publication date Assignee Title
US4170142A (en) * 1977-07-15 1979-10-09 Electric Power Research Institute, Inc. Linear transducer array and method for both pulse-echo and holographic acoustic imaging
US4287769A (en) * 1978-06-01 1981-09-08 Massachusetts Institute Of Technology Apparatus and method whereby wave energy is correlated with geometry of a manufactured part or the like or to positional relationships in a system
US4368641A (en) * 1981-01-30 1983-01-18 Powers Manufacturing, Inc. Out-of-round detector
WO1985000229A1 (en) * 1983-06-27 1985-01-17 Cochlea Corporation A system to recognize a geometry parameter of unknown objects with continuous wave acoustic energy
EP0160346A2 (en) * 1984-05-03 1985-11-06 Motoren-Reparatiebedrijf Pinkster B.V. acting under the name of Heuft-Qualiplus Apparatus for detecting containers having a deviating property
EP0246711A2 (en) * 1986-05-22 1987-11-25 Infa B.V. A device for recognising the shape and dimension of bottles or the like

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4170142A (en) * 1977-07-15 1979-10-09 Electric Power Research Institute, Inc. Linear transducer array and method for both pulse-echo and holographic acoustic imaging
US4287769A (en) * 1978-06-01 1981-09-08 Massachusetts Institute Of Technology Apparatus and method whereby wave energy is correlated with geometry of a manufactured part or the like or to positional relationships in a system
US4368641A (en) * 1981-01-30 1983-01-18 Powers Manufacturing, Inc. Out-of-round detector
WO1985000229A1 (en) * 1983-06-27 1985-01-17 Cochlea Corporation A system to recognize a geometry parameter of unknown objects with continuous wave acoustic energy
EP0160346A2 (en) * 1984-05-03 1985-11-06 Motoren-Reparatiebedrijf Pinkster B.V. acting under the name of Heuft-Qualiplus Apparatus for detecting containers having a deviating property
EP0246711A2 (en) * 1986-05-22 1987-11-25 Infa B.V. A device for recognising the shape and dimension of bottles or the like

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5615778A (en) * 1991-07-29 1997-04-01 Rwe Entsorgung Aktiengesellschaft Process to sort waste mixtures

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