GB2195802A - Pattern recognition system - Google Patents

Pattern recognition system Download PDF

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Publication number
GB2195802A
GB2195802A GB08622939A GB8622939A GB2195802A GB 2195802 A GB2195802 A GB 2195802A GB 08622939 A GB08622939 A GB 08622939A GB 8622939 A GB8622939 A GB 8622939A GB 2195802 A GB2195802 A GB 2195802A
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United Kingdom
Prior art keywords
filter
tool
pattern recognition
holographic
pattern
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.)
Withdrawn
Application number
GB08622939A
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GB8622939D0 (en
Inventor
Carol David Daniel
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.)
General Electric Co PLC
Original Assignee
General Electric Co PLC
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
Application filed by General Electric Co PLC filed Critical General Electric Co PLC
Priority to GB08622939A priority Critical patent/GB2195802A/en
Publication of GB8622939D0 publication Critical patent/GB8622939D0/en
Publication of GB2195802A publication Critical patent/GB2195802A/en
Withdrawn legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06V—IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
    • G06V10/00—Arrangements for image or video recognition or understanding
    • G06V10/88—Image or video recognition using optical means, e.g. reference filters, holographic masks, frequency domain filters or spatial domain filters

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Multimedia (AREA)
  • Theoretical Computer Science (AREA)
  • Length Measuring Devices By Optical Means (AREA)
  • Holo Graphy (AREA)

Abstract

A three-dimensional object, 11, is illuminated by a source of coherent radiation, 9, and radiation scattered from the object is passed through a transform lens, 3, 5, and a holographic filter, 1, encoded with a reference pattern corresponding to an object to be recognised and detected by an array 7. <IMAGE>

Description

SPECIFICATION Pattern recognition system This invention relates to pattern recognition systems.
Pattern recognition systems are often used in, for example, robotics, for the recognition of such three dimensional objects as tools.
These systems include for example optical correlators in which an image of the tool to be recognised is formed and compared with a reference image, and edge enhancement system in which an image of the tool is modified to enable further optical processing of the image to be carried out. In either case it is necessary for the system to include a holographic filter, this taking the form of a matched spatial filter such as a Vander Lugt filter in the case of the correlator, and a high pass filter in the case of the edge enhancement system. Such systems thus suffer the disadvantage that it is generally necessary for them to include a spatial light modulator to produce the two dimensional coherent image of the tool necessary to address a holographic.
filter, spatial light modulators being relatively expensive components.
It is an object of the present invention to provide a pattern recognition system for the recognition of three dimensional objects, in which a holographic filter is incorporated in the system, but in which it is not necessary to provide a spatial light modulator.
According to the present invention a pattern recognition system for the recognition of a three dimensional object, the system incorporating a holographic filter, is characterised in that it includes a source of coherent radiation arranged to illuminate the object, and means for directing coherent radiation from the source scattered by the object onto the holographic filter for processing by the filter.
One pattern recognition system in accordance with the invention will now be described, by way of example only, with reference to the accompanying figure which is a schematic diagram of the system.
Referring to the figure, the system includes a frequency plane optical correlator comprising a Vander Lugt filter 1 holographically incoded with a reference pattern. The filter 1 is placed between two Fourier transform lenses 3 in the focal plane of each of the lenses 3, 5. A two dimensional detector array 7 is placed in the focal plane remote from the filter 1 of the lens 5. A single mode laser diode 9, whose function is described hereafter, is also provided.
In use of the system the single mode laser diode 9 is used to illuminate a tool 11 which it is required to recognise. Means (not shown) are provided for directing radiation from the laser diode 9 which has been scattered by the tool 11 through the transform lens 3 onto the filter 1. The filter 1 thus produces an output which is the product of the Fourier transform of the pattern of light which is scattered by and is thus representative of the tool 11 and is subsequently received by the filter 1, and the reference pattern. The spatial distribution of Hght-received by the detector array 7 is thus representative of the correlation between the pattern of light scattered by the tool and the reference pattern. By appropriate calibration it can thus be determined whether the tool 11 corresponds to a predetermined tool.
It will be appreciated that whilst the system described above by way of example, is an optical correlator comprising a Vander Lugt filter, the invention is also applicable to a correlator including a quantity of optically non-linear material, for example a single crystal of bismuth germanium oxide, such a correlator using the process of three wave mixing within the crystal to enable scattered coherent light from the object to be recognised to be compared to a variety of different reference patterns.
It will also be appreciated that whilst the invention is particularly applicable to optical correlators, it is also applicable to other pattern recognition systems incorporating holographic filters, for example systems including high pass filters for edge enhancement purposes.
1. A pattern recognition system for the recognition of a three dimensional object, the system incorporating a holographic filter characterised in that it includes a source of coherent radiation arranged to illuminate the object, and means for directing coherent radiation from the source scattered by the object onto the holographic filter for processing by the filter.
2. A system according to Claim 1 in which said filter is a Vander Lugt filter.
3. A system according to Claim 1 in which said filter is a high pass filter.
4. A pattern recognition system for the recognition of a three dimensional object substantially as hereinbefore described with reference to the accompanying drawing.
**WARNING** end of DESC field may overlap start of CLMS **.

Claims (4)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Pattern recognition system This invention relates to pattern recognition systems. Pattern recognition systems are often used in, for example, robotics, for the recognition of such three dimensional objects as tools. These systems include for example optical correlators in which an image of the tool to be recognised is formed and compared with a reference image, and edge enhancement system in which an image of the tool is modified to enable further optical processing of the image to be carried out. In either case it is necessary for the system to include a holographic filter, this taking the form of a matched spatial filter such as a Vander Lugt filter in the case of the correlator, and a high pass filter in the case of the edge enhancement system. Such systems thus suffer the disadvantage that it is generally necessary for them to include a spatial light modulator to produce the two dimensional coherent image of the tool necessary to address a holographic. filter, spatial light modulators being relatively expensive components. It is an object of the present invention to provide a pattern recognition system for the recognition of three dimensional objects, in which a holographic filter is incorporated in the system, but in which it is not necessary to provide a spatial light modulator. According to the present invention a pattern recognition system for the recognition of a three dimensional object, the system incorporating a holographic filter, is characterised in that it includes a source of coherent radiation arranged to illuminate the object, and means for directing coherent radiation from the source scattered by the object onto the holographic filter for processing by the filter. One pattern recognition system in accordance with the invention will now be described, by way of example only, with reference to the accompanying figure which is a schematic diagram of the system. Referring to the figure, the system includes a frequency plane optical correlator comprising a Vander Lugt filter 1 holographically incoded with a reference pattern. The filter 1 is placed between two Fourier transform lenses 3 in the focal plane of each of the lenses 3, 5. A two dimensional detector array 7 is placed in the focal plane remote from the filter 1 of the lens 5. A single mode laser diode 9, whose function is described hereafter, is also provided. In use of the system the single mode laser diode 9 is used to illuminate a tool 11 which it is required to recognise. Means (not shown) are provided for directing radiation from the laser diode 9 which has been scattered by the tool 11 through the transform lens 3 onto the filter 1. The filter 1 thus produces an output which is the product of the Fourier transform of the pattern of light which is scattered by and is thus representative of the tool 11 and is subsequently received by the filter 1, and the reference pattern. The spatial distribution of Hght-received by the detector array 7 is thus representative of the correlation between the pattern of light scattered by the tool and the reference pattern. By appropriate calibration it can thus be determined whether the tool 11 corresponds to a predetermined tool. It will be appreciated that whilst the system described above by way of example, is an optical correlator comprising a Vander Lugt filter, the invention is also applicable to a correlator including a quantity of optically non-linear material, for example a single crystal of bismuth germanium oxide, such a correlator using the process of three wave mixing within the crystal to enable scattered coherent light from the object to be recognised to be compared to a variety of different reference patterns. It will also be appreciated that whilst the invention is particularly applicable to optical correlators, it is also applicable to other pattern recognition systems incorporating holographic filters, for example systems including high pass filters for edge enhancement purposes. CLAIMS
1. A pattern recognition system for the recognition of a three dimensional object, the system incorporating a holographic filter characterised in that it includes a source of coherent radiation arranged to illuminate the object, and means for directing coherent radiation from the source scattered by the object onto the holographic filter for processing by the filter.
2. A system according to Claim 1 in which said filter is a Vander Lugt filter.
3. A system according to Claim 1 in which said filter is a high pass filter.
4. A pattern recognition system for the recognition of a three dimensional object substantially as hereinbefore described with reference to the accompanying drawing.
GB08622939A 1986-09-24 1986-09-24 Pattern recognition system Withdrawn GB2195802A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB08622939A GB2195802A (en) 1986-09-24 1986-09-24 Pattern recognition system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB08622939A GB2195802A (en) 1986-09-24 1986-09-24 Pattern recognition system

Publications (2)

Publication Number Publication Date
GB8622939D0 GB8622939D0 (en) 1987-01-14
GB2195802A true GB2195802A (en) 1988-04-13

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Family Applications (1)

Application Number Title Priority Date Filing Date
GB08622939A Withdrawn GB2195802A (en) 1986-09-24 1986-09-24 Pattern recognition system

Country Status (1)

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GB (1) GB2195802A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2236418A (en) * 1989-09-30 1991-04-03 William Morton Holographic logic device

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1305248A (en) * 1970-07-23 1973-01-31
US4053228A (en) * 1975-12-12 1977-10-11 Michael Schiller Finger identification
US4174179A (en) * 1977-08-24 1979-11-13 Guy Indebetouw Continuous feed holographic correlator for randomly oriented workpieces
US4227805A (en) * 1978-01-25 1980-10-14 Michael Schiller Finger identification apparatus and method
EP0021982A1 (en) * 1979-06-18 1981-01-07 Omnium De Realisations Industrielles Et Commerciales Method and device for the optical processing of objects through intercorrelation with rings
GB2154331A (en) * 1984-02-16 1985-09-04 Standard Telephones Cables Ltd Coherent light optical processor

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1305248A (en) * 1970-07-23 1973-01-31
US4053228A (en) * 1975-12-12 1977-10-11 Michael Schiller Finger identification
US4174179A (en) * 1977-08-24 1979-11-13 Guy Indebetouw Continuous feed holographic correlator for randomly oriented workpieces
US4227805A (en) * 1978-01-25 1980-10-14 Michael Schiller Finger identification apparatus and method
EP0021982A1 (en) * 1979-06-18 1981-01-07 Omnium De Realisations Industrielles Et Commerciales Method and device for the optical processing of objects through intercorrelation with rings
GB2154331A (en) * 1984-02-16 1985-09-04 Standard Telephones Cables Ltd Coherent light optical processor

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2236418A (en) * 1989-09-30 1991-04-03 William Morton Holographic logic device

Also Published As

Publication number Publication date
GB8622939D0 (en) 1987-01-14

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