Apparatus and methods are provided for measuring vehicle wheel alignment
characteristics. According to one embodiment, during a first measurement
cycle, spatial coordinates of multiple points on the wheel are obtained
by positioning a vision sensor at various angular offsets relative to the
wheel, the multiple points representative of samples from each of the
various angular offsets. After the first measurement cycle and before the
second measurement cycle, the wheel is rotated at least a partial
revolution. During the second measurement cycle, spatial coordinates of
multiple points on the wheel are obtained by positioning the vision
sensor at various angular offsets relative to the wheel, the multiple
points representative of samples from each of the various angular
offsets. Finally, one or more characteristics of the wheel are determined
based upon the spatial coordinates collected during the first measurement
cycle and the spatial coordinates collected during the second measurement
cycle.