CA2002547C - Sensing the shape of an object - Google Patents
Sensing the shape of an object Download PDFInfo
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- CA2002547C CA2002547C CA002002547A CA2002547A CA2002547C CA 2002547 C CA2002547 C CA 2002547C CA 002002547 A CA002002547 A CA 002002547A CA 2002547 A CA2002547 A CA 2002547A CA 2002547 C CA2002547 C CA 2002547C
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- imaging system
- directional screen
- radiation
- optical axis
- image
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- 238000003384 imaging method Methods 0.000 claims abstract description 74
- 230000005855 radiation Effects 0.000 claims description 40
- 230000003287 optical effect Effects 0.000 claims description 26
- 238000000034 method Methods 0.000 claims description 21
- 239000010437 gem Substances 0.000 claims description 4
- 229910001751 gemstone Inorganic materials 0.000 claims description 4
- 239000010432 diamond Substances 0.000 abstract description 19
- 229910003460 diamond Inorganic materials 0.000 abstract description 17
- XKRFYHLGVUSROY-UHFFFAOYSA-N argon Substances [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 3
- 229910052786 argon Inorganic materials 0.000 description 3
- 238000004458 analytical method Methods 0.000 description 2
- 101100387911 Caenorhabditis elegans dop-2 gene Proteins 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 238000012937 correction Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000013383 initial experiment Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000010137 moulding (plastic) Methods 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/24—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures
- G01B11/25—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures by projecting a pattern, e.g. one or more lines, moiré fringes on the object
- G01B11/2518—Projection by scanning of the object
- G01B11/2522—Projection by scanning of the object the position of the object changing and being recorded
Abstract
In order to determine the external profile of a diamond, particularly a large diamond which has re-entrant features, an elongate and thin beam is projected onto the diamond whilst the diamond is rotated about an axis normal to the beam; an imaging system is used to image from one side the line along which the beam strikes the diamond, this image being formed on a diffraction grating which is tilted in accordance with the Scheimpflug condition and in order to employ the first order beam of the diffraction grating. The image on the diffraction grating is viewed with a second imaging system. Furthermore, there may be a substantial improvement in light capture. The arrangement is applicable to systems other than those for determining profile.
Description
The present invention relates to a method of imaging an object parts of which are substantially further from the imaging system than other parts. The problems arising were initially encountered when photographing buildings where, without correction, the tops of the buildings appear too narrow and foreshortened. However, whilst being of general applicability, the invention has particular applicability to sensing the shape of an object by scanning or projecting onto the object an incident beam which, the incident radiation, as seen in cross section normal to the direction of propagation of the radiation is elongated and thin, whereby the radiation strikes the object along a line; in other words, there is either a stationary beam which is elongate and thin in this section, or there is a scanned beam which sweeps out an area which is elongate and thin in this section. The line is imaged along an axis at a substantial angle to the plane of the incident beam (the plane of the beam is that plane normal to the smallest dimension of the beam). In other words, the shape is detected using a thin sheet of light (a narrow beam), whether continuous or scanned, which is played upon the article; observation off the axis of the beam, i.e. from one side, reveals the profile or contour of the object. The object itself can be rotated with respect 2~~~5~~
to the beam so that the whole of its surface is observed. An imaging system is used to image the points where the beam strikes the article. Such a method is disclosed in GB-A-2 103 355 (equivalent to US 4 529 305). Normally, visible light will be used, but at least in theory other forms of radiation, such as infra-red or ultra-violet, could be used.
The present invention is applicable to any suitable object and any suitable profile, e.g. profile/contour measurement of machine parts - it is especially useful for objects which are difficult to measure with a micrometer, such as screws, gears, turbine blades and plastic mouldings, and for fragile objects requiring a non-contact method. However, the invention has been developed with respect to gemstones, particularly diamonds, and is especially useful for large stones, e.g. having a weight greater than say 10 ct (2 g), with re-entrant features. The invention can be used to determine the shape of objects which are mounted and rotated.
In general, to obtain an image which geometrically reproduces the object, the objective of the imaging system should be tilted from the normal to the object, and the imaging plane should be tilted with respect to the objective and with respect to the normal to,the object. Such an arrangement is known in photography.
where tilting bellows are used on a camera, and the Scheimpflug condition specifies the angle of the image plane. There is a problem with this type of imaging. The light enters the imaging system at a large angle of incidence, and much is lost by reflection. Also, due to the constraints of the system, it is difficult to change the magnification (as may be required e.g. to examine more closely a re-entrant feature in a diamond).
THE INVENTION:
According to the present invention, an image of the object is formed a directional screen such as a diffraction grating and the directional screen is viewed using an imaging system. More particularly, an incident beam, looking along the incident beam, is elongate and thin, can be scanned or projected onto the object so that, as seen in cross-section normal to the direction of propagation, the incident radiation is elongate and thin;
in this way, the beam strikes the object along a line, the line being imaged along an axis at a substantial angle to the plane of the incident beam. The invention extends to apparatus for imaging the objects and comprising diffraction grating means, a first imaging system for forming an image of the object on the directional screen, and a second imaging system for forming an image of the first image, i.e. the image on the direction screen.
to the beam so that the whole of its surface is observed. An imaging system is used to image the points where the beam strikes the article. Such a method is disclosed in GB-A-2 103 355 (equivalent to US 4 529 305). Normally, visible light will be used, but at least in theory other forms of radiation, such as infra-red or ultra-violet, could be used.
The present invention is applicable to any suitable object and any suitable profile, e.g. profile/contour measurement of machine parts - it is especially useful for objects which are difficult to measure with a micrometer, such as screws, gears, turbine blades and plastic mouldings, and for fragile objects requiring a non-contact method. However, the invention has been developed with respect to gemstones, particularly diamonds, and is especially useful for large stones, e.g. having a weight greater than say 10 ct (2 g), with re-entrant features. The invention can be used to determine the shape of objects which are mounted and rotated.
In general, to obtain an image which geometrically reproduces the object, the objective of the imaging system should be tilted from the normal to the object, and the imaging plane should be tilted with respect to the objective and with respect to the normal to,the object. Such an arrangement is known in photography.
where tilting bellows are used on a camera, and the Scheimpflug condition specifies the angle of the image plane. There is a problem with this type of imaging. The light enters the imaging system at a large angle of incidence, and much is lost by reflection. Also, due to the constraints of the system, it is difficult to change the magnification (as may be required e.g. to examine more closely a re-entrant feature in a diamond).
THE INVENTION:
According to the present invention, an image of the object is formed a directional screen such as a diffraction grating and the directional screen is viewed using an imaging system. More particularly, an incident beam, looking along the incident beam, is elongate and thin, can be scanned or projected onto the object so that, as seen in cross-section normal to the direction of propagation, the incident radiation is elongate and thin;
in this way, the beam strikes the object along a line, the line being imaged along an axis at a substantial angle to the plane of the incident beam. The invention extends to apparatus for imaging the objects and comprising diffraction grating means, a first imaging system for forming an image of the object on the directional screen, and a second imaging system for forming an image of the first image, i.e. the image on the direction screen.
The invention employs a diffraction grating (or the like) as a directional screen which passes reflected or refracted radiation to the imaging system. The diffraction grating acts as a directional mirror, and any suitable imaging system can be used after the diffraction grating.
Normally, an image of the object will be formed on the diffraction grating.
Normally, the diffraction grating first order beam is employed. The grating is oriented so that the reflected or transmitted diffracted beam is at the correct angle for the final imaging system, the diffraction grating normally being normal to the final imaging system. The cone angle of incidence on the grating should be smaller than the diffraction angle. A
blazed or tuned grating can be used, arranged so that a large percentage of the radiation (e.g. 80% - 90%) is in one beam; the beam is preferably the first order beam but it is possible to blaze for the second, third or fourth order beams.
The grating enables much more radiation to pass into the imaging system as there can be normal incidence on the imaging system, enabling the aperture to be maximised and avoiding marked reflection losses; however, the grating maintains the same image quality without introducing any further aberrations. Furthermore, the magnification can be changed very simply, merely by exchanging the lens system, or a zoom can be used. The image size or the resolution (or both) can be changed.
Any suitable grating or the equivalent can be used as the direction screen -the grating may be holographic. Any device which substantially or effectively has the same effect as a diffraction grating can be used as the directional screen, provided it has sufficient planarity to give suitable imaging. The pitch of spacing of the grating or equivalent should be smaller than the resolution required for the object being examined, e.g. a grating of 10~ resolution for high resolution examination and a grating of SOp resolution for lower resolution examination.
Any suitable techniques can be introduced. For example, the light from the object can be subjected simultaneously to multiple analysis (different analyses of separate beams), e.g. using two or more imaging systems in association with two or more wavelengths or one or more beam sputters, and two or more gratings (e.g. using visible light and near infra-red).
Any suitable radiation can be used, preferred radiations being the near infra-red and visible.
Normally, an image of the object will be formed on the diffraction grating.
Normally, the diffraction grating first order beam is employed. The grating is oriented so that the reflected or transmitted diffracted beam is at the correct angle for the final imaging system, the diffraction grating normally being normal to the final imaging system. The cone angle of incidence on the grating should be smaller than the diffraction angle. A
blazed or tuned grating can be used, arranged so that a large percentage of the radiation (e.g. 80% - 90%) is in one beam; the beam is preferably the first order beam but it is possible to blaze for the second, third or fourth order beams.
The grating enables much more radiation to pass into the imaging system as there can be normal incidence on the imaging system, enabling the aperture to be maximised and avoiding marked reflection losses; however, the grating maintains the same image quality without introducing any further aberrations. Furthermore, the magnification can be changed very simply, merely by exchanging the lens system, or a zoom can be used. The image size or the resolution (or both) can be changed.
Any suitable grating or the equivalent can be used as the direction screen -the grating may be holographic. Any device which substantially or effectively has the same effect as a diffraction grating can be used as the directional screen, provided it has sufficient planarity to give suitable imaging. The pitch of spacing of the grating or equivalent should be smaller than the resolution required for the object being examined, e.g. a grating of 10~ resolution for high resolution examination and a grating of SOp resolution for lower resolution examination.
Any suitable techniques can be introduced. For example, the light from the object can be subjected simultaneously to multiple analysis (different analyses of separate beams), e.g. using two or more imaging systems in association with two or more wavelengths or one or more beam sputters, and two or more gratings (e.g. using visible light and near infra-red).
Any suitable radiation can be used, preferred radiations being the near infra-red and visible.
The invention will be further described, by way of example, with reference to the accompanying drawing, which is a schematic diagram showing the determination of the shape of a diamond.
A diamond 1 is mounted on a dop 2 which is carried by a mechanism 3 which can move the diamond 1 about any of three orthogonal axes. The diamond 1 is illuminated by an illuminator 4 which provides an incident beam which, as seen in cross-section normal to the direction of propagation of the beam, is elongate and thin, or which is in the form of a spot which is scanned along a line; in either case, the beam strikes the diamond 1 along a line. By imaging the line 1' along an axis at a substantial angle a to the plane of the incident beam, the shape or contour of the diamond 1 along said line 1' can be seen. This technique is described in GB-A-2 103 355.
To examine the shape of the line 1', two imaging systems are used. A first imaging system is represented by two lenses 5,6 with an intervening aperture 7 which forms a telecentric stop; the aperture 7 is shown at the focal point of the lens 5 and also at the focal point of the lens 6. This imaging system forms an image of the line 1', i.e. of the object in question, on a diffraction grating 8. The diffraction grating 8 is at an angle to the optical axis of the first imaging system 5,6 which is determined by the Scheimpflug condition. Also, the angle of incidence onto the diffraction grating 8 corresponds to the first order beam of the grating 8. The image on the diffraction grating 8 is viewed by a second imaging system which is represented by a lens 9, and the image is formed on a detector 10 which can be, for instance, a TV camera or a CCD
array. The detector 10 is shown connected to a microprocessor 11. In turn, the microprocessor 11 can be connected to the first and/or second imaging system, to the mechanism 3 and to the illuminator 4. The microprocessor 11 is programmed in a way now known in order to map the whole shape of the diamond 1 as the diamond 1 is rotated by the mechanism In one arrangement, the illuminator 4 has two beams available, namely a high resolution beam which is 10~ wide and 3mm long and a low resolution beam which is 50~
wide and lOmm long - these dimensions are of a cross-section of the beam in a direction normal to the direction of propagation of th beam. Many diamonds are longer than 3mm and thus the high resolution beam will only illuminate part of the length of the diamond 1. It would, however, be possible for the illuminator 4 to have some zoom arrangement so that the beam corresponds to the length of the diamond 1. To provide high resolution and low resolution alternatives, the first imaging system can be arranged to give a 1:1 ratio or alternatively 2:1 or 4:1 magnification onto the grating 8 (or could be a zoom system), so that the image on the grating 8 is roughly the same size whether the high resolution beam or the low resolution beam is being used. It is also possible to provide two different magnifications or a zoom in the second imaging system 9. All these variations can be under the control of the computer 11. In one automatic system, the low resolution beam is used until a re-entrant feature is detected - limiting rays may not enter a re-entrant feature; the microprocessor il then automatically changes the system over to a high resolution beam in order to map the re-entrant.
Example The illuminator 4 is either an air-cooled argon ion 50 mW
laser manufactured by Omnichrome (used for the initial experiments) or a HeNe 15 mW laser manufactured by Spectra Physics of the USA. For an argon ion laser, the preferred wavelength is 514.5 nm, though other wavelengths can be used such as 488 nm. If a HeNe laser is used, the wavelength is 632.8 nm.
Lenses 5 and 6 are manufactured by Spindler & Hoyer GmbH, part number 322239 and each has a focal length of 140 mm; in alternative arrangements; the ratio of the focal lengths of the lenses 5 and 6 can be changed to give magnifications of 1X, 2X and 3X.
Aperture 7 is a variable iris of diameter 5 to 20 mm.
The diffraction grating 8 is a holographic grating manufactured by American Holographic Inc. of size 30 mm X
a 30mm X 6mm with 1500 lineslmm optimised for SOOnm operation (for the argon ion laser). A different grating would be required for HeNe laser wavelength due to the different position of the diffracted orders. The angle « and angular position of the grating would also be different due to operating at a different wavelength.
Two different lenses can be used for the imaging lens 9 - having different focal lengths, namely 120mm positioned 240mm from the grating 8 to give 1X magnification, and 60mm positioned 60mm from the grating 8 to give 8X magnification. To change the magnification, the different lenses are dropped in and out of th eoptical path of the imaging system.
The detector 10 is a CCD TV camera or a Vidicon TV camera.
The following distances are used: - diamond 1 to lens 5 - 140mm;
- lens 5 to aperature 7 - 140mm;
- aperture 7 to lens 6 - 140mm; and - lens 6 to grating 8 - 140mm.
The present invention has been described above purely by way of example, and modifications can be made within the spirit of the invention.
8a
A diamond 1 is mounted on a dop 2 which is carried by a mechanism 3 which can move the diamond 1 about any of three orthogonal axes. The diamond 1 is illuminated by an illuminator 4 which provides an incident beam which, as seen in cross-section normal to the direction of propagation of the beam, is elongate and thin, or which is in the form of a spot which is scanned along a line; in either case, the beam strikes the diamond 1 along a line. By imaging the line 1' along an axis at a substantial angle a to the plane of the incident beam, the shape or contour of the diamond 1 along said line 1' can be seen. This technique is described in GB-A-2 103 355.
To examine the shape of the line 1', two imaging systems are used. A first imaging system is represented by two lenses 5,6 with an intervening aperture 7 which forms a telecentric stop; the aperture 7 is shown at the focal point of the lens 5 and also at the focal point of the lens 6. This imaging system forms an image of the line 1', i.e. of the object in question, on a diffraction grating 8. The diffraction grating 8 is at an angle to the optical axis of the first imaging system 5,6 which is determined by the Scheimpflug condition. Also, the angle of incidence onto the diffraction grating 8 corresponds to the first order beam of the grating 8. The image on the diffraction grating 8 is viewed by a second imaging system which is represented by a lens 9, and the image is formed on a detector 10 which can be, for instance, a TV camera or a CCD
array. The detector 10 is shown connected to a microprocessor 11. In turn, the microprocessor 11 can be connected to the first and/or second imaging system, to the mechanism 3 and to the illuminator 4. The microprocessor 11 is programmed in a way now known in order to map the whole shape of the diamond 1 as the diamond 1 is rotated by the mechanism In one arrangement, the illuminator 4 has two beams available, namely a high resolution beam which is 10~ wide and 3mm long and a low resolution beam which is 50~
wide and lOmm long - these dimensions are of a cross-section of the beam in a direction normal to the direction of propagation of th beam. Many diamonds are longer than 3mm and thus the high resolution beam will only illuminate part of the length of the diamond 1. It would, however, be possible for the illuminator 4 to have some zoom arrangement so that the beam corresponds to the length of the diamond 1. To provide high resolution and low resolution alternatives, the first imaging system can be arranged to give a 1:1 ratio or alternatively 2:1 or 4:1 magnification onto the grating 8 (or could be a zoom system), so that the image on the grating 8 is roughly the same size whether the high resolution beam or the low resolution beam is being used. It is also possible to provide two different magnifications or a zoom in the second imaging system 9. All these variations can be under the control of the computer 11. In one automatic system, the low resolution beam is used until a re-entrant feature is detected - limiting rays may not enter a re-entrant feature; the microprocessor il then automatically changes the system over to a high resolution beam in order to map the re-entrant.
Example The illuminator 4 is either an air-cooled argon ion 50 mW
laser manufactured by Omnichrome (used for the initial experiments) or a HeNe 15 mW laser manufactured by Spectra Physics of the USA. For an argon ion laser, the preferred wavelength is 514.5 nm, though other wavelengths can be used such as 488 nm. If a HeNe laser is used, the wavelength is 632.8 nm.
Lenses 5 and 6 are manufactured by Spindler & Hoyer GmbH, part number 322239 and each has a focal length of 140 mm; in alternative arrangements; the ratio of the focal lengths of the lenses 5 and 6 can be changed to give magnifications of 1X, 2X and 3X.
Aperture 7 is a variable iris of diameter 5 to 20 mm.
The diffraction grating 8 is a holographic grating manufactured by American Holographic Inc. of size 30 mm X
a 30mm X 6mm with 1500 lineslmm optimised for SOOnm operation (for the argon ion laser). A different grating would be required for HeNe laser wavelength due to the different position of the diffracted orders. The angle « and angular position of the grating would also be different due to operating at a different wavelength.
Two different lenses can be used for the imaging lens 9 - having different focal lengths, namely 120mm positioned 240mm from the grating 8 to give 1X magnification, and 60mm positioned 60mm from the grating 8 to give 8X magnification. To change the magnification, the different lenses are dropped in and out of th eoptical path of the imaging system.
The detector 10 is a CCD TV camera or a Vidicon TV camera.
The following distances are used: - diamond 1 to lens 5 - 140mm;
- lens 5 to aperature 7 - 140mm;
- aperture 7 to lens 6 - 140mm; and - lens 6 to grating 8 - 140mm.
The present invention has been described above purely by way of example, and modifications can be made within the spirit of the invention.
8a
Claims (27)
1. A method of sensing the shape of an object, comprising:
scanning or projecting onto the object an incident beam of radiation whereby the radiation, as seen in cross-section normal to the direction of propagation of the radiation, is elongate and thin, whereby the incident radiation lies substantially in a plane and strikes the object along a line;
forming an image of said line on a directional screen which is at an angle to the optical axis of light coming from the object, said angle being in accordance with the Scheimpflug condition, said optical axis being at a substantial angle to the plane of said incident radiation; and viewing the directional screen using an imaging system to form a final image, the directional screen being normal to the optical axis of the imaging system which forms the final image.
scanning or projecting onto the object an incident beam of radiation whereby the radiation, as seen in cross-section normal to the direction of propagation of the radiation, is elongate and thin, whereby the incident radiation lies substantially in a plane and strikes the object along a line;
forming an image of said line on a directional screen which is at an angle to the optical axis of light coming from the object, said angle being in accordance with the Scheimpflug condition, said optical axis being at a substantial angle to the plane of said incident radiation; and viewing the directional screen using an imaging system to form a final image, the directional screen being normal to the optical axis of the imaging system which forms the final image.
2. The method of Claim 1, wherein the directional screen is a diffraction grating.
3. The method of Claim 1 or 2, wherein the optical axis of light coming from the object is aligned with the first order beam of the directional screen.
4. The method of Claim 1, 2 or 3, wherein said object is a gemstone.
5. A method of sensing the shape of an object, comprising:
scanning or projecting onto the object an incident beam of radiation whereby the radiation, as seen in cross-section normal to the direction of propagation of the radiation, is elongate and thin, whereby the incident radiation lies substantially in a plane and strikes the object along a line;
forming an image of said line on a directional screen using a first imaging system whose optical axis is at a substantial angle to the plane of said incident radiation, the directional screen being at an angle to said optical axis which is in accordance with the Scheimpflug condition; and viewing the directional screen using a second imaging system, the directional screen being normal to the optical axis of the second imaging system.
scanning or projecting onto the object an incident beam of radiation whereby the radiation, as seen in cross-section normal to the direction of propagation of the radiation, is elongate and thin, whereby the incident radiation lies substantially in a plane and strikes the object along a line;
forming an image of said line on a directional screen using a first imaging system whose optical axis is at a substantial angle to the plane of said incident radiation, the directional screen being at an angle to said optical axis which is in accordance with the Scheimpflug condition; and viewing the directional screen using a second imaging system, the directional screen being normal to the optical axis of the second imaging system.
6. The method of Claim 5, wherein the directional screen is a diffraction grating.
7. The method of Claim 5 or 6, wherein the optical axis of the first imaging system is aligned with the first order beam of the directional screen.
8. The method of Claim 5, 6 or 7, wherein the first imaging system has a magnification other than unity.
9. The method of Claim 5, 6, 7 or 8, wherein the object is a gemstone.
10. A method of sensing the shape of an object, comprising:
scanning or projecting onto the object an incident beam of radiation whereby the radiation, as seen in cross-section normal to the direction of propagation of the radiation, is elongate and thin, whereby the incident radiation lies substantially in a plane and strikes the object along a line;
using a first imaging system to form an image of said line on a directional screen which is at an angle to the optical axis of said first imaging system, said angie being in accordance with the Scheimpflug condition, said optical axis being at a substantial angle to the plane of said incident radiation, said first imaging system comprising a telecentric stop;
and viewing the directional screen using a second imaging system to form a final image, the directional screen being normal to the optical axis of said second imaging system.
scanning or projecting onto the object an incident beam of radiation whereby the radiation, as seen in cross-section normal to the direction of propagation of the radiation, is elongate and thin, whereby the incident radiation lies substantially in a plane and strikes the object along a line;
using a first imaging system to form an image of said line on a directional screen which is at an angle to the optical axis of said first imaging system, said angie being in accordance with the Scheimpflug condition, said optical axis being at a substantial angle to the plane of said incident radiation, said first imaging system comprising a telecentric stop;
and viewing the directional screen using a second imaging system to form a final image, the directional screen being normal to the optical axis of said second imaging system.
11. The method of Claim 10, wherein the directional screen is a diffraction grating.
12. The method of Claim 10 or 11, wherein the axis of the first imaging system is aligned with the first order beam of the directional screen.
13. The method of Claim 10, 11 or 12, wherein the first imaging system has a magnification other than unity.
14. The method of Claim 10, 11, 12 or 13, wherein said object is a gemstone.
15. Apparatus for sensing the shape of an object, the apparatus comprising:
means for scanning or projecting onto the object an incident beam of radiation which radiation, as seen in cross-section normal to the direction of propagation of the radiation, is elongate and thin, whereby the incident radiation will lie substantially in a plane and strike the object along a line;
means for forming an image of said line on a directional screen which is at an angle to the optical axis of light coming from the object, said angle being in accordance with the Scheimpflug condition, said optical axis being at a substantial angle to the plane of said incident radiation; and an imaging system for viewing the directional screen to form a final image the directional screen being normal to the optical axis of the imaging system which forms the final image.
means for scanning or projecting onto the object an incident beam of radiation which radiation, as seen in cross-section normal to the direction of propagation of the radiation, is elongate and thin, whereby the incident radiation will lie substantially in a plane and strike the object along a line;
means for forming an image of said line on a directional screen which is at an angle to the optical axis of light coming from the object, said angle being in accordance with the Scheimpflug condition, said optical axis being at a substantial angle to the plane of said incident radiation; and an imaging system for viewing the directional screen to form a final image the directional screen being normal to the optical axis of the imaging system which forms the final image.
16. The apparatus of Claim 15, wherein the directional screen is a diffraction grating.
17. The apparatus of Claim 15 or 16, wherein said optical axis of light coming from the object is aligned with the first order beam of the directional screen.
18. Apparatus for sensing the shape of an object, the apparatus comprising:
means for scanning or projecting onto the object an incident beam of radiation which radiation, as seen in cross-section normal to the direction of propagation of the radiation, is elongate and thin, whereby the incident radiation will lie substantially in a plane and strike the object along a line;
a first imaging system for imaging said line along an axis at a substantial angle to the plane of said incident radiation;
a directional screen which is at an angle to said axis which is in accordance with the Scheimpflug condition; and a second imaging system having an optical axis normal to the directional screen, for forming an image of said line, whereby the latter image represents the shape of the object along said line.
means for scanning or projecting onto the object an incident beam of radiation which radiation, as seen in cross-section normal to the direction of propagation of the radiation, is elongate and thin, whereby the incident radiation will lie substantially in a plane and strike the object along a line;
a first imaging system for imaging said line along an axis at a substantial angle to the plane of said incident radiation;
a directional screen which is at an angle to said axis which is in accordance with the Scheimpflug condition; and a second imaging system having an optical axis normal to the directional screen, for forming an image of said line, whereby the latter image represents the shape of the object along said line.
19. The apparatus of Claim 18, wherein the directional screen is a diffraction grating.
20. The apparatus of Claim 18 or 19, wherein the optical axis of the first imaging system is aligned with the first order beam of the directional screen.
21. The apparatus of Claim 18, 19 or 20, wherein the first imaging system has a magnification other than unity.
22. Apparatus for sensing the shape of an object, comprising:
means for scanning or projecting onto the object an incident beam of radiation which radiation, as seen in cross-section normal to the direction of propagation of the radiation, is elongate and thin, whereby the incident radiation will lie substantially in a plane and strike the object along a line;
a directional screen;
means comprising a first imaging system for forming an image of said line on the directional screen, the optical axis of the first imaging system being at a substantial angle to the plane of said incident radiation, and said first imaging system comprising a telecentric stop, the directional screen being at an angie to the optical axis of the first imaging system which is in accordance with the Scheimpflug condition; and a second imaging system for forming an image of the image on the directional screen, the second imaging system having an optical axis normal to the directional screen, whereby the image formed by the second imaging system represents the shape of the object along said line.
means for scanning or projecting onto the object an incident beam of radiation which radiation, as seen in cross-section normal to the direction of propagation of the radiation, is elongate and thin, whereby the incident radiation will lie substantially in a plane and strike the object along a line;
a directional screen;
means comprising a first imaging system for forming an image of said line on the directional screen, the optical axis of the first imaging system being at a substantial angle to the plane of said incident radiation, and said first imaging system comprising a telecentric stop, the directional screen being at an angie to the optical axis of the first imaging system which is in accordance with the Scheimpflug condition; and a second imaging system for forming an image of the image on the directional screen, the second imaging system having an optical axis normal to the directional screen, whereby the image formed by the second imaging system represents the shape of the object along said line.
23. The apparatus of Claim 22, wherein the directional screen is a diffraction grating.
24. The apparatus of Claim 22 or 23, wherein the optical axis of the first imaging system is aligned with the first order beam of the directional screen.
25. The apparatus of Claim 22, 23 or 24, wherein the first imaging system has a magnification other than unity.
26. A method of imaging an object parts of which are substantially further from an imaging system than other parts, the method comprising:
forming an image of the object on a directional screen using means comprising a first imaging system in turn comprising a telecentric stop; and viewing the directional screen using a second imaging system whose optical axis is at a substantial angle to the optical axis of said first imaging system.
forming an image of the object on a directional screen using means comprising a first imaging system in turn comprising a telecentric stop; and viewing the directional screen using a second imaging system whose optical axis is at a substantial angle to the optical axis of said first imaging system.
27. Apparatus for imaging an object parts of which are substantially further from the imaging system than other parts, the apparatus comprising:
a directional screen;
means comprising a first imaging system for forming an image of the object on the directional screen, the first imaging system comprising a telecentric stop; and a second imaging system for forming an image of the image on the directional screen, the optical axis of the second imaging system being at a substantial angle to the optical axis of the first imaging system.
a directional screen;
means comprising a first imaging system for forming an image of the object on the directional screen, the first imaging system comprising a telecentric stop; and a second imaging system for forming an image of the image on the directional screen, the optical axis of the second imaging system being at a substantial angle to the optical axis of the first imaging system.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8826224.1 | 1988-11-09 | ||
| GB888826224A GB8826224D0 (en) | 1988-11-09 | 1988-11-09 | Sensing shape of object |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2002547A1 CA2002547A1 (en) | 1990-05-09 |
| CA2002547C true CA2002547C (en) | 2002-01-08 |
Family
ID=10646564
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002002547A Expired - Fee Related CA2002547C (en) | 1988-11-09 | 1989-11-08 | Sensing the shape of an object |
Country Status (10)
| Country | Link |
|---|---|
| US (1) | US5076698A (en) |
| EP (1) | EP0368647B1 (en) |
| JP (1) | JPH03183904A (en) |
| AU (1) | AU619056B2 (en) |
| CA (1) | CA2002547C (en) |
| DE (1) | DE68908347T2 (en) |
| GB (2) | GB8826224D0 (en) |
| IE (1) | IE62699B1 (en) |
| IL (1) | IL92228A (en) |
| ZA (1) | ZA898492B (en) |
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-
1988
- 1988-11-09 GB GB888826224A patent/GB8826224D0/en active Pending
-
1989
- 1989-11-06 AU AU44434/89A patent/AU619056B2/en not_active Ceased
- 1989-11-07 IL IL92228A patent/IL92228A/en not_active IP Right Cessation
- 1989-11-07 US US07/432,912 patent/US5076698A/en not_active Expired - Fee Related
- 1989-11-08 ZA ZA898492A patent/ZA898492B/en unknown
- 1989-11-08 CA CA002002547A patent/CA2002547C/en not_active Expired - Fee Related
- 1989-11-09 IE IE361289A patent/IE62699B1/en not_active IP Right Cessation
- 1989-11-09 DE DE89311582T patent/DE68908347T2/en not_active Expired - Fee Related
- 1989-11-09 EP EP89311582A patent/EP0368647B1/en not_active Expired - Lifetime
- 1989-11-09 JP JP1292100A patent/JPH03183904A/en active Pending
- 1989-11-09 GB GB8925307A patent/GB2226133B/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| DE68908347T2 (en) | 1993-11-25 |
| ZA898492B (en) | 1990-08-29 |
| EP0368647A2 (en) | 1990-05-16 |
| GB2226133A (en) | 1990-06-20 |
| CA2002547A1 (en) | 1990-05-09 |
| IE62699B1 (en) | 1995-02-22 |
| GB8925307D0 (en) | 1989-12-28 |
| US5076698A (en) | 1991-12-31 |
| GB8826224D0 (en) | 1988-12-14 |
| EP0368647B1 (en) | 1993-08-11 |
| IL92228A0 (en) | 1990-07-26 |
| AU4443489A (en) | 1990-05-17 |
| JPH03183904A (en) | 1991-08-09 |
| DE68908347D1 (en) | 1993-09-16 |
| AU619056B2 (en) | 1992-01-16 |
| EP0368647A3 (en) | 1990-12-19 |
| IL92228A (en) | 1992-07-15 |
| IE893612L (en) | 1990-05-09 |
| GB2226133B (en) | 1993-05-05 |
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| EEER | Examination request | ||
| MKLA | Lapsed |