Scanner device and device for measuring three-dimensional shape of object
A laser beam (L 50 ) is reflected by a light beam scanning device ( 60 ) and irradiated onto a hologram recording medium ( 45 ). On the hologram recording medium ( 45 ), an image ( 35 ) of a linear scatter body is recorded as a hologram by using reference light that converges on a scanning origin (B). The light beam scanning device ( 60 ) bends the laser beam (L 50 ) at the scanning origin (B) and irradiates the laser beam onto the hologram recording medium ( 45 ). At this time, by changing a bending mode of the laser beam with time, an irradiation position of the bent laser beam (L 60 ) on the hologram recording medium ( 45 ) is changed with time. Diffracted light (L 45 ) from the hologram recording medium ( 45 ) produces a reproduction image ( 35 ) of the linear scatter body on a light receiving surface (R) of the stage 210 . When an object is placed on the light receiving surface (R), 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.
1. A linear illumination device that projects a line pattern of light onto an object, comprising:
a coherent light source that generates a coherent light beam,
a hologram recording medium on which an image of a scatter body having a shape corresponding to the line pattern is recorded, and
a light beam scanning device that irradiates the light beam onto the hologram recording medium and scans the light beam so that an irradiation position of the light beam on the hologram recording medium changes with time, wherein
the image of the scatter body is recorded as a hologram on the hologram recording medium as a form of interference fringes which reproduce the image of the scatter body when the light beam is given as illumination light advancing toward the respective irradiation points on the hologram recording medium along respective particular optical paths,
wherein the image of the scatter body recorded on the hologram recording medium is reproduced as a reproduction image when the light beam irradiates from a single irradiation position on the hologram recording medium,
wherein multiple reproduction images of the scatter body are produced as the light beam moves between irradiation positions on the hologram recording medium, wherein the multiple reproduction images are identical to each other and produced at a same position irrespective of the actual irradiation position used to create the reproduction image,
the coherent light source generates a light beam with a wavelength capable of reproducing the reproduction image of the scatter body,
the light beam scanning device scans the light beam so that an irradiation direction of the light beam onto the hologram recording medium is along one of said particular optical paths, and
the line pattern is projected by reproduction light of the hologram obtained from the hologram recording medium.
2. The linear illumination device according to claim 1 , wherein
an image of one or a plurality of linear scatter bodies parallel to each other is recorded on the hologram recording medium, and a line pattern including one or a plurality of lines parallel to each other is projected by reproduction light of a hologram.
3. The linear illumination device according to claim 1 , wherein
the hologram recording medium is divided into a plurality of divided regions, and an image of one or a plurality of linear scatter bodies is recorded in each of the divided regions, line patterns each including one or a plurality of lines are projected by reproduction lights of holograms obtained from the respective divided regions, 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.
4. The linear illumination device according to claim 3 , wherein
the light beam scanning device 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, wherein i=1, 2, 3 . . . , is projected on an i-th position in space when scanning an i-th divided region and the light beam scanning device has a function of changing a projecting position of the line pattern onto the object with time.
5. The linear illumination device according to claim 3 , wherein
the hologram recording medium is divided so that a plurality of horizontally long and narrow divided regions are arranged vertically, and hologram recording is carried out so that longitudinal directions of the respective divided regions and longitudinal directions of reproduction images obtained from the respective divided regions become parallel to each other.
6. The linear illumination device according to claim 1 , wherein
the light beam scanning device bends the light beam at a scanning origin, irradiates the bent light beam onto the hologram recording medium, and changes an irradiation position of the bent light beam on the hologram recording medium with time by changing a bending mode of the light beam with time,
the image of the scatter body is recorded as a hologram on the hologram recording medium by using reference light that converges on a specific convergence point or reference light that diverges from a specific convergence point, and
the light beam scanning device scans the light beam by setting the convergence point as the scanning origin.
7. The linear illumination device according to claim 6 , wherein
the image of the scatter body is recorded on the hologram recording medium by using reference light that three-dimensionally converges or diverges along a side surface of a cone whose tip is on the convergence point.
8. The linear illumination device according to claim 6 , wherein
the image of the scatter body is recorded on the hologram recording medium by using reference light that two-dimensionally converges or diverges along a plane including the convergence point.
9. The linear illumination device according to claim 1 , wherein
the light beam scanning device changes the irradiation position of the light beam on the hologram recording medium with time by irradiating the light beam onto the hologram recording medium while moving the light beam parallel,
the image of the scatter body is recorded as a hologram on the hologram recording medium by using reference light composed of a parallel light flux, and
the light beam scanning device scans the light beam by irradiating the light beam onto the hologram recording medium in a direction parallel to the reference light.
10. The linear illumination device according to claim 4 , wherein
the hologram recording medium is divided so that a plurality of horizontally long and narrow divided regions are arranged vertically, and hologram recording is carried out so that longitudinal directions of the respective divided regions and longitudinal directions of reproduction images obtained from the respective divided regions become parallel to each other.