SCANNER DEVICE AND DEVICE FOR MEASURING THREE-DIMENSIONAL SHAPE OF OBJECT

• US 20130076857A1
• Filed: 09/07/2010
• Published: 03/28/2013
• Est. Priority Date: 09/07/2010
• Status: Active Grant

• Current Assignee: Dai Nippon Printing Company Limited
• Original Assignee: Dai Nippon Printing Company Limited
• Inventors: Kurashige, Makio, Oyagi, Yasuyuki, Ishida, Kazutoshi, Takanokura, Tomoe
• Granted Patent: US 9,116,504 B2
• Time in Patent Office: Days
• US Class Current: 348/40
• CPC Class Codes: G01B 11/24 for measuring contours or curvatures
• CPC Class Codes: G01B 11/25 by projecting a pattern, e.g. one or more lines, moiré fringes on the object G01B11/255 takes precedence ; image analysis for depth or shape recovery G06T7/50
• CPC Class Codes: G01B 11/2518 Projection by scanning of the object
• CPC Class Codes: G02B 27/48 Laser speckle optics
• CPC Class Codes: G03H 1/0005 Adaptation of holography to specific applications holographic optical element G02B5/32; holographic scanner G02B26/106; recognition using holographic mask G06V10/88; holographic memories G11B7/0065, G11C13/042
• CPC Class Codes: G03H 1/0443 Digital holography, i.e. recording holograms with digital recording means holobject computation G03H1/0866
• CPC Class Codes: G03H 1/2286 Particular reconstruction light G03H1/24 takes precedence; Beam properties
• CPC Class Codes: G03H 1/30 discrete holograms only
• CPC Class Codes: G03H 1/32 Systems for obtaining speckle elimination
• CPC Class Codes: G03H 2001/0033 in hologrammetry for measuring or analysing
• CPC Class Codes: G03H 2001/0413 for recording transmission holograms
• CPC Class Codes: G03H 2001/0415 for recording reflection holograms
• CPC Class Codes: G03H 2001/0439 for recording Holographic Optical Element [HOE] HOE per se G02B5/32
• CPC Class Codes: G03H 2001/2231 Reflection reconstruction
• CPC Class Codes: G03H 2001/2234 Transmission reconstruction
• CPC Class Codes: G03H 2001/2255 Holobject out of Fourier or hologram planes
• CPC Class Codes: G03H 2001/2292 Using scanning means
• CPC Class Codes: G03H 2210/11 Amplitude modulating object
• CPC Class Codes: G03H 2210/20 2D object
• CPC Class Codes: G03H 2222/36 Scanning light beam
• CPC Class Codes: G03H 2222/42 : Reference beam at recording stage
• CPC Class Codes: G03H 2222/54 : Convergent beam
• CPC Class Codes: G03H 2222/56 : Conjugated beam
• CPC Class Codes: G03H 2223/14 : Diffuser, e.g. lens array, random phase mask
• CPC Class Codes: H04N 7/18 : Closed-circuit television [CCTV] systems, i.e. systems in which the video signal is not broadcast

Abstract

A laser beam is reflected by a light beam scanning device and irradiated onto a hologram recording medium. On the hologram recording medium, an image of a linear scatter body is recorded as a hologram by using reference light that converges on a scanning origin. The light beam scanning device bends the laser beam at the scanning origin and irradiates the laser beam onto the hologram recording medium. At this time, by changing a bending mode of the laser beam with time, an irradiation position of the bent laser beam on the hologram recording medium is changed with time. Diffracted light from the hologram recording medium produces a reproduction image of the linear scatter body on a light receiving surface of the stage. When an object is placed on the light receiving surface, a line pattern is projected by hologram reproduction light, so that the projected image is captured and a three-dimensional shape of the object is measured.

Claims

1. A scanner apparatus that scans an object (M) with a line pattern (U) of light and imports surface information of the object (M), comprising:

an illumination unit (100, 110) that projects the line pattern (U) of light onto the object (M);

a pattern scanning mechanism (200) that changes a projection position of the line pattern (U) on the object (M) with time; and

an imaging unit (300, 301 to 303) that captures an image of the object (M) onto which the line pattern (U) is projected from a predetermined direction, and imports surface information of the object (M), wherein

the illumination unit (100, 110) includes

a coherent light source (50) that generates a coherent light beam (L50),

a hologram recording medium (45, 46, 85) on which an image (35) of a scatter body (30) having a shape corresponding to the line pattern (U) is recorded, and

a light beam scanning device (60, 65) that irradiates the light beam (L60, L65) onto the hologram recording medium (45, 46, 85) and scans the light beam so that an irradiation position of the light beam (L60, L65) on the hologram recording medium (45, 46, 85) changes with time, wherein

an image of the scatter body (30) is recorded as a hologram on the hologram recording medium (45, 46, 85) by using reference light (L23, Lref) irradiated along an optical path,

the coherent light source (50) generates a light beam (L50) with a wavelength capable of reproducing the image (35) of the scatter body,

the light beam scanning device (60, 65) scans the light beam (L60, L65) so that an irradiation direction of the light beam (L60, L65) onto the hologram recording medium (45, 46, 85) is along the optical path of the reference light (L23, Lref), and

the line pattern (U) is projected by reproduction light of a hologram obtained from the hologram recording medium (45, 46, 85).

2. The scanner apparatus according to claim 1, wherein

an image (35) of one or a plurality of linear scatter bodies (30) parallel to each other is recorded on the hologram recording medium (45, 46, 85), and a line pattern (U) including one or a plurality of lines parallel to each other is projected by reproduction light of a hologram.

3. The scanner apparatus according to claim 2, wherein

the pattern scanning mechanism (200) includes

a placing stage (210) for placing an object (M) thereon, and

a conveyance device (220) that moves the placing stage (210) in a direction orthogonal to a line constituting the line pattern (U).

4. The scanner apparatus according to claim 2, wherein

the pattern scanning mechanism (200) includes

a placing stage (210) for placing an object (M) thereon, and

a conveyance device that moves the illumination unit (100, 110) in a direction orthogonal to a line constituting the line pattern (U) with respect to the placing stage (210).

5. The scanner apparatus according to claim 2, wherein

the pattern scanning mechanism (200) includes an optical system that changes a direction of reproduction light of a hologram obtained from the illumination unit (100, 110), and scans a line pattern (U) projected by the reproduction light in a direction orthogonal to a line constituting the line pattern (U).

6. The scanner apparatus according to claim 1, wherein

the hologram recording medium (88) is divided into a plurality of divided regions (88-1, 88-2, 88-3, . . . , 88-n), and an image of one or a plurality of linear scatter bodies (30) is recorded in each of the divided regions (88-1, 88-2, 88-3, . . . , 88-n), line patterns each including one or a plurality of lines are projected by reproduction lights of holograms obtained from the respective divided regions (88-1, 88-2, 88-3, . . . , 88-n), and a line pattern projected by reproduction light of a hologram obtained from one divided region and a line pattern projected by reproduction light of a hologram obtained from another divided region are formed at spatially different positions.

7. The scanner apparatus according to claim 6, wherein

the light beam scanning device (60, 65) scans a light beam on the divided regions in an order of a first divided region, a second divided region, a third divided region, . . . , so that an i-th line pattern is projected on an i-th position in space when scanning an i-th (i=1, 2, 3 . . . ) divided region, and the light beam scanning device (60, 65) commonly serves as the pattern scanning mechanism.

8. The scanner apparatus according to claim 6, wherein

the hologram recording medium (88) is divided so that a plurality of horizontally long and narrow divided regions (88-1, 88-2, 88-3, . . . , 88-n) are arranged vertically, and hologram recording is carried out so that longitudinal directions of the respective divided regions (88-1, 88-2, 88-3, . . . , 88-n) and longitudinal directions of reproduction images obtained from the respective divided regions (88-1, 88-2, 88-3, . . . , 88-n) become parallel to each other.

9. The scanner apparatus according to claim 1, wherein

the light beam scanning device (60) bends the light beam (L50) at a scanning origin (B), irradiates the bent light beam (L60) onto the hologram recording medium (45), and changes an irradiation position of the bent light beam (L60) on the hologram recording medium (45) with time by changing a bending mode of the light beam (L50) with time,

the image of the scatter body (30) is recorded as a hologram on the hologram recording medium (45) by using reference light (L23) that converges on a specific convergence point (C) or reference light (L23) that diverges from a specific convergence point (C), and

the light beam scanning device (60) scans the light beam (L60) by setting the convergence point (C) as the scanning origin (B).

10. The scanner apparatus according to claim 9, wherein

the image of the scatter body (30) is recorded on the hologram recording medium (45) by using reference light that three-dimensionally converges or diverges along a side surface of a cone whose tip is on the convergence point (C).

11. The scanner apparatus according to claim 9, wherein

the image of the scatter body (30) is recorded on the hologram recording medium (45) by using reference light that two-dimensionally converges or diverges along a plane including the convergence point (C).

12. The scanner apparatus according to claim 1, wherein

the light beam scanning device (65) changes the irradiation position of the light beam (L65) on the hologram recording medium (46) with time by irradiating the light beam (L65) onto the hologram recording medium (46) while moving the light beam (L65) parallel,

the image (35) of the scatter body (30) is recorded as a hologram on the hologram recording medium (46) by using reference light (Lref) composed of a parallel light flux, and

the light beam scanning device (65) scans the light beam (L65) by irradiating the light beam (L65) onto the hologram recording medium (46) in a direction parallel to the reference light (Lref).

13. An object surface information acquisition method for importing surface information of an object (M) by projecting a line pattern (U) of light onto the object (M), comprising:

a preparation step of creating a hologram recording medium (45, 46, 85) by recording an image (35) of a scatter body (30) for forming a line pattern (U) as a hologram on a recording medium (40, 80);

a projection step of irradiating a coherent light beam (L60) onto the hologram recording medium (45, 46, 85) in a state where the object (M) is disposed at a position to be irradiated with reproduction light of a hologram obtained from the hologram recording medium (45, 46, 85) and scanning the light beam (L60) on the hologram recording medium (45, 46, 85) so that an irradiation position changes with time, and projecting the line pattern (U) onto the object (M); and

an imaging step of capturing an image of the object (M) onto which the line pattern (U) is projected from a predetermined direction, and importing surface information of the object (M), wherein

in the preparation step, coherent illumination light (L12) is irradiated onto the scatter body (30) so that scattered light (L30) obtained from the scatter body (30) is used as object light, coherent light (L23, Lref) with the same wavelength as that of the illumination light (L12) is irradiated onto the recording medium (40, 80) along an optical path so as to be used as reference light, and interference fringes formed by the object light and the reference light are recorded on the recording medium (40, 80) to prepare the hologram recording medium (45, 46, 85), and

in the projection step, a light beam (L60, L65) with a wavelength capable of reproducing the image (35) of the scatter body is scanned so as to advance toward an irradiation position on the hologram recording medium (45, 46, 85) by passing through an optical path along the optical path of the reference light (L23, Lref).

14. A scanner apparatus that scans an object (M) with a line pattern (U) of light and imports surface information of the object (M), comprising:

an illumination unit (120) that projects the line pattern (U) of light onto the object (M);

a pattern scanning mechanism (200) that changes a projection position of the line pattern (U) on the object (M) with time; and

an imaging unit (300, 301 to 303) that captures an image of the object (M) onto which the line pattern (U) is projected from a predetermined direction, and imports surface information of the object (M), wherein

the illumination unit (120) includes

a coherent light source (50) that generates a coherent light beam (L50),

a microlens array (48) including a collection of a large number of independent lenses, and

a light beam scanning device (60) that irradiates the light beam (L50) onto the microlens array (48) and scans the light beam so that an irradiation position of the light beam (L60) on the microlens array (48) changes with time, wherein

each of the independent lenses included in the microlens array (48) has a function of refracting light irradiated from the light beam scanning device (60) and forming a linear irradiation region (I) on a nearby surface (R) near the object (M), and is configured so that all irradiation regions (I) formed by the independent lenses become substantially the same common region on the nearby surface (R).

15. A scanner apparatus that scans an object (M) with a line pattern (U) of light and imports surface information of the object (M), comprising:

an illumination unit (100, 110, 120) that projects the line pattern (U) of light onto the object (M);

a pattern scanning mechanism (200) that changes a projection position of the line pattern (U) on the object (M) with time; and

an imaging unit (300, 301 to 303) that captures an image of the object (M) onto which the line pattern (U) is projected from a predetermined direction, and imports surface information of the object (M), wherein

the illumination unit (100, 110, 120) includes

a coherent light source (50) that generates a coherent light beam (L50),

a light beam scanning device (60, 65) that carries out beam scanning by controlling either or both of a direction and a position of the light beam (L50), and

an optical diffusing element (45, 46, 48) that diffuses and emits an incident light beam,

the light beam scanning device (60, 65) emits the light beam (L50) generated by the coherent light source (50) toward the optical diffusing element (45, 46, 48), and scans the light beam so that an incidence position of the light beam (L60) on the light diffusing element (45, 46, 48) changes with time, and

the optical diffusing element (45, 46, 48) has a function of forming a linear irradiation region (I) on a nearby surface (R) near the object (M) by diffusing an incident light beam, and is configured so that formed irradiation regions (I) become substantially the same common region on the nearby surface (R) regardless of the incidence position of the light beam.

16. An apparatus for measuring a three-dimensional shape of an object (M), comprising:

an illumination unit (100, 110) that projects a line pattern (U) of light onto the object (M);

an imaging unit (300, 301 to 303) that captures an image of the object (M) onto which the line pattern (U) is projected from a predetermined direction; and

a shape analysis unit (400) that creates three-dimensional shape data (T) of the object (M) by analyzing the line pattern (U) on the image (G) captured with the imaging unit (300, 301 to 303), wherein

the illumination unit (100, 110) includes

a coherent light source (50) that generates a coherent light beam (L50),

a hologram recording medium (45, 46, 85) on which an image (35) of a scatter body (30) having a shape corresponding to the line pattern (U) is recorded, and

a light beam scanning device (60, 65) that irradiates the light beam (L60, L65) onto the hologram recording medium (45, 46, 85) and scans the light beam so that an irradiation position of the light beam (L60, L65) on the hologram recording medium (45, 46, 85) changes with time, wherein

an image of the scatter body (30) is recorded as a hologram on the hologram recording medium (45, 46, 85) by using reference light (L23, Lref) irradiated along an optical path,

the coherent light source (50) generates a light beam (L50) with a wavelength capable of reproducing the image (35) of the scatter body,

the light beam scanning device (60, 65) scans the light beam (L60, L65) so that an irradiation direction of the light beam (L60, L65) onto the hologram recording medium (45, 46, 85) is along the optical path of the reference light (L23, Lref), and

the line pattern (U) is projected by reproduction light of a hologram obtained from the hologram recording medium (45, 46, 85).

17. The apparatus for measuring a three-dimensional shape of an object according to claim 16, wherein

an image (35) of one or a plurality of linear scatter bodies (30) is recorded on the hologram recording medium (45, 46, 85), and a line pattern (U) including one or a plurality of lines is projected by reproduction light of a hologram.

18. The apparatus for measuring a three-dimensional shape of an object according to claim 16, wherein

the hologram recording medium (88) is divided into a plurality of divided regions (88-1, 88-2, 88-3, . . . , 88-n), and an image of one or a plurality of linear scatter bodies (30) is recorded in each of the divided regions (88-1, 88-2, 88-3, . . . , 88-n), line patterns each including one or a plurality of lines are projected by reproduction lights of holograms obtained from the respective divided regions (88-1, 88-2, 88-3, . . . , 88-n), and a line pattern projected by reproduction light of a hologram obtained from one divided region and a line pattern projected by reproduction light of a hologram obtained from another divided region are formed at spatially different positions.

19. The apparatus for measuring a three-dimensional shape of an object according to claim 18, wherein

the light beam scanning device (60, 65) scans a light beam on the divided regions in an order of a first divided region, a second divided region, a third divided region, . . . , so that an i-th line pattern is projected on an i-th position in space when scanning an i-th (i=1, 2, 3 . . . ) divided region to change a projection position of the line pattern (U) on the object (M) with time.

20. The apparatus for measuring a three-dimensional shape of an object according to claim 18, wherein

the hologram recording medium (88) is divided so that a plurality of horizontally long and narrow divided regions (88-1, 88-2, 88-3, . . . , 88-n) are arranged vertically, and hologram recording is carried out so that longitudinal directions of the respective divided regions (88-1, 88-2, 88-3, . . . , 88-n) and longitudinal directions of reproduction images obtained from the respective divided regions (88-1, 88-2, 88-3, . . . , 88-n) become parallel to each other.

21. The apparatus for measuring a three-dimensional shape of an object according to claim 16, wherein

an image of a horizontal grid-like scatter body (30A) including a plurality of linear scatter bodies (30A-1, 30A-2, 30A-3, . . . , 30A-n) extending horizontally and arranged vertically parallel to each other is recorded on the hologram recording medium (45, 46, 85), and a line pattern including a plurality of lines (U1, U2, U3, . . . , Un) parallel to each other is projected by reproduction light of a hologram.

22. The apparatus for measuring a three-dimensional shape of an object according to claim 16, wherein

an image of a horizontal grid-like scatter body (30A) including a plurality of linear scatter bodies (30A-1, 30A-2, 30A-3, . . . , 30A-n) extending horizontally and arranged vertically parallel to each other and an image of a vertical grid-like scatter body (30B) including a plurality of linear scatter bodies (30B-1, 30B-2, 30B-3, . . . , 30B-m) extending vertically and arranged horizontally parallel to each other are superimposed and recorded on the hologram recording medium (45, 46, 85), and a reticulated grid-like line pattern is projected by reproduction light of a hologram.

23. The apparatus for measuring a three-dimensional shape of an object according to claim 16, wherein

an image of a reticulated grid-like scatter body (30C) is recorded on the hologram recording medium (45, 46, 85), and a reticulated grid-like line pattern is projected by reproduction light of a hologram.

24. The apparatus for measuring a three-dimensional shape of an object according to claim 16, further comprising:

a placing stage (210) for placing an object (M) thereon; and

a conveyance device (220) that moves one of the illumination unit (100, 110) and the placing stage (210) with respect to the other.

25. The apparatus for measuring a three-dimensional shape of an object according to claim 16, further including:

an optical system that changes a direction of reproduction light of a hologram obtained from the illumination unit (100, 110) so that a line pattern (U) projected by the reproduction light is scanned.

26. The apparatus for measuring a three-dimensional shape of an object according to claim 16, wherein

the imaging unit (300) includes a plurality of cameras (301 to 303) that capture an image of an object (M) from different directions, respectively, and

the shape analysis unit (400) creates three-dimensional shape data (T) of the object (M) by analyzing line patterns (U) on images (G) captured with the plurality of cameras (301 to 303).