| 摘要 |
PURPOSE:To measure simultaneously and with a high accuracy a moving speed of a measuring object and a distance to the measuring object, by providing an arithmetic part, and an optical system for generating two kinds of irradiating light beams whose waist position is shifted and also whose irradiating areas to the measuring object become the same on a projecting part. CONSTITUTION:A projecting part 1 generates a speckle pattern by projecting a coherent light to a moving measuring object 4, and constituted of a laser light source 5, and an optical system 9 for generating the first and the second irradiating light beams 7, 8 from a laser light 6 which the laser light source 5 is radiated and irradiating them to the measuring object 4. The first and the second irradiating lights 7, 8 are shifted as to beam waist positions W1, W2, respectively, and also have the same irradiating area against the measuring object 4. The first irradiating light 7 and the second irradiating light 8 are generated by the first optical system 9A and the second optical system 9B, respectively. An arithmetic part 3 calculates a moving speed (v) of the measuring object 4 and a distance R to the measuring object 4 by deriving a mutual correlation value of a speckle signal which has been obtained by each photodetecting part 2A, 2B.
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