A Novel Auto-Focus Measurement System for Mesh Membrane

摘要

In this paper, we develop the auto-focus measurement system which includes the hardware and software systems. The hardware system is composed of both modules of the motion stage and the auto-focus optic-mechanism. And the software system consists of two phases: (1) training the response surface model (RSM) for auto-focus technology in offline phase and (2) automatically capturing mesh images by RSM and robustly measuring holes by the area-based diameter (ABD) and average diameter (AD) in online phase. The experiments presented that the proposed auto-focus technology using RSM can effectively obtain the correct focusing position. The accuracy of the diameter on a hole can reach up at most 0.891 um using the above two algorithms. The successful measure rate is almost 98%; the measure time is averagely 4.8 seconds per mesh. The above results revealed that the proposed system is not only robust for the auto-focus technology but also efficient and effective for the mesh membrane measurement.