Patent ID: 7958564

Claim:
A scanning measurement instrument for performing autonomous scanning measurement while making a spherical tip contact a measurement surface of a workpiece, the instrument comprising: a scanning probe, the scanning probe comprising: a probe body; the spherical tip, which contacts the workpiece; and a stylus supported in a deflective manner with respect to the probe body and connected to the tip at an end; a moving unit for moving the workpiece and the scanning probe relative to each other such that a contact position of the measurement surface and the tip is moved along the measurement surface; a movement distance detection unit for detecting the movement distance of the scanning probe moved by the moving unit; a deflect on detection unit for detecting the deflection of the stylus with respect to the probe body; a data processor for calculating the coordinates of the center position of the tip according to the movement distance of the scanning probe detected by the movement distance detection unit and the deflection of the stylus detected by the deflection detection unit; a path information holding unit for holding information about a path of the center position of the tip during the autonomous scanning measurement performed with the scanning probe, the path being, with respect to the center position of the tip, from a center position of the tip immediately before the center position of the tip, to a center position of the tip located a predetermined measurement pitch before the center position of the tip, in the direction opposite a movement direction of the scanning probe; a path reference direction setting unit for calculating an approximate straight line direction from the information about the path of the center position of the tip stored in the path information holding unit to set the direction as a path reference direction; a traveling direction setting unit for setting the path reference direction set by the path reference direction setting unit as a traveling direction of the scanning probe; a movement control unit for controlling the relative movement of the scanning probe moved by the moving unit such that the scanning probe is moved in the traveling direction set by the traveling direction setting unit; and a normal direction setting unit for setting the normal direction of the measurement surface according to the direction of a vector obtained from the outer product of a vector indicating the traveling direction set by the traveling direction setting unit and a normal vector of a scanning restraining section specified in advance.