Surface Profiling Using a Modified Shadow Moir é Technique

The paper presents a modified shadow moire system that improves the surface profile measurement in accuracy, efficiency and convenience. First, the new system incorporates a multigrid least-square unwrapping algorithm in conjunction with phase-shifting technique. Furthermore, the current system incorporates a contour detection technique in fringe processing to facilitate the measurement in non-rectangular or irregular shaped surfaces and hollow areas. A new system calibration approach is also implemented based on a real-time image subtraction scheme