CORRECTION METHOD FOR MEASUREMENT OBJECT DISPLACEMENT WITH SPECKLE PATTERN USING LASER BEAM, AND DEVICE THEREFOR

摘要

PURPOSE: To provide a displacement correction for a measurement object by processing a signal from a CCD camera with an arithmetic operation device or the like, using a laser speckle pattern. ;CONSTITUTION: A laser oscillator 4 uses visible light of high brightness and directivity for drawing a stable speckle pattern 3 on a measurement object 1. A CCD camera 5 photographs the pattern 3 drawn on the object 1 and converts the pattern 3 to a digital signal via an A/D converter 6. The travel state of the object 1 (i.e., speckle pattern) is, then, continuously stored in the memory elements of a processing device 7, and the displacement of a given occulting point is operated on the basis of CCD picture element intervals (reference length) for display and output as numerical information. Also, the laser beam of constant position marks 10 is irradiated to the object 1, and intervals between the marks 10 are measured in correspondence to the number of the CCD picture elements. Thereafter, a distance between the object 1 and the camera 5 is derived, using a known factor stored in the device 7, thereby calculating a correction for the measured displacement.;COPYRIGHT: (C)1996,JPO