A ball-based intermediary target technique is presented to position moving machine vision measurement system and
to realize data registration under different positions. Large-sized work-piece measurement based on machine vision faces
several problems: limited viewing angle, range and accuracy of measurement inversely proportional. To measure the
whole work-piece conveniently and precisely, the idea that using balls as registration target is proposed in this paper.
Only a single image of the ball target is required from each camera then the vision system is fully calibrated (intrinsic
and extrinsic camera parameters). When the vision system has to be moved to measure the whole work-piece, one
snapshot of the ball target in the common view can position the system. Then data registration can be fulfilled. To
achieve more accurate position of ball’s center, an error correction model is established.
Sub-aperture stitching (SAS) testing method is an effective way to extend the lateral and vertical dynamic range of a
conventional interferometer. However, the center of each sub-aperture could be in error because of the complex motion
of the mechanical platform. To eliminate the affection of lateral location error in the final stitching result, a lateral
location error compensation algorithm is introduced and the ability of the algorithm to compensate the lateral location
error is analyzed. Finally, a 152.4mm concave parabolic mirror is tested using SAS method with the compensation
algorithm. The result showed that the algorithm can effectively compensate the lateral location error caused by the
mechanical motion. The proposal of the algorithm can reduce high requirement of mechanical platform, which provides
a feasible method for the practical application of the engineering.