Patent ID: 7355682

Claim:
A system for measuring the distance from a first point spaced away from a surface of an object to a second point on a surface of an object along an axis extending through the first point and the second point, comprising: a first projection assembly for projecting a first plane of light so that the first plane of light contains the second point and intersects the surface of the object to form a first light stripe on the surface; a second projection assembly for projecting a second plane of light so that the second plane of light contains the second point and intersects the surface of the object to form a second light stripe on the surface, the first light stripe intersecting the second light stripe at the second point; an imaging device for detecting the position of the second point by sensing the intersection of the first light stripe and the second light stripe at the second point; and a distance calculator for calculating the distance between the first point and the second point along the axis using the position of the second point detected by the imaging device, wherein the distance between the first point and the second point is determined from the detected position of the second point and the imaging device detects the position of a third point along the axis, the distance between the first point and the third point being predetermined, and wherein the distance calculator determines the distance between the second point and the third point and subtracts the distance between the second point and the third point from the distance between the first point and the third point for determining the distance between the first point and the second point.