Patent ID: 8363101

Claim:
A method for optically measuring an external thread profile, in particular at a pipe end, comprising the steps of: producing a thread in a production line in a clocked manner; and continuously measuring the thread in line from beginning to end by illuminating and scanning a profile of the thread in tangential relationship to a pipe cross section on the basis of a relative movement, comprised of rotation and translation, between a pipe and at least one optical measuring unit arranged in a counter light and comprised of an illumination and a camera, wherein a position of the pipe end in relation to a position of the measuring unit is continuously determined in longitudinal pipe direction by means of laser triangulation and a thread length is calculated during measurement while taking into account possible changes in position; setting a scanning speed in such a manner that a time for scanning the thread profile, while taking into account a required resolution of the camera, lies within a cycle time necessary for a production of a next thread; capturing an image of the thread profile by the camera to generate optical signals; evaluating the optical signals; and comparing the optical signals with target specifications.