Abstract: An automatic inspection system for evaluating dimensional and geometrical characteristics of apertures or bores within production parts is disclosed. The system includes a profile sensor, having an outwardly extending probe, that is mounted to a probe manipulator. The probe manipulator is configured for moving the profile sensor so that the tip of the probe moves along axial and circumferential paths of a cylindrical scanning sequence in which the probe tip traces out geometrical elements along the interior contour of the aperture. As the probe tip is moved through the scanning sequence, signals representative of the circumferential and axial position of the probe tip and the radial deflection of the probe tip are periodically supplied to a control circuit that converts these signals to a digital format and controls movement of the probe through the next portion of the scanning sequence.