Patent ID: 8650939

Claim:
A surface texture measuring machine for measuring a surface texture of an object, comprising: a stage on which the object is mounted; a contact-type detector having a stylus that is brought into contact with a surface of the object; an image probe that captures an image of the surface of the object; a relative movement mechanism that relatively moves the stage against the contact-type detector and the image probe and/or relatively moves the contact-type detector and the image probe against the stage; and a controller that controls a drive of the relative movement mechanism and executes processing on measurement data obtained by the contact-type detector and image data captured by the image probe, the controller including: a center position calculating unit that, when the image probe enters position data of at least three points on a circular contour of a circular concave portion or a circular convex portion of the object, approximates the entered position data to a circle to obtain a center position of the circle; and a stylus setting unit that, when the center position calculating unit obtains the center position, operates the relative movement mechanism to position the stylus of the contact-type detector at the center position, wherein: one of the stylus of the contact-type detector and the image probe is located at an offset position not to interfere with the other of the stylus of the contact-type detector and the image probe that is used for a measurement, the surface texture measuring machine includes an offset amount storage unit that stores an offset amount of a tip end of the stylus of the contact-type detector and the image probe, and when the center position is obtained by the center position calculating unit, the stylus setting unit operates the relative movement mechanism to position the image probe at the center position and then operates the relative movement mechanism by the offset amount stored in the offset amount storage unit to position the stylus of the contact-type detector at the center position.