A Self-Projected Light-Section Method for Fast Three-Dimensional Shape Inspection

We present a novel self-projected light-section method that can realize fast three-dimensional (3-D) shape inspection by reducing pixel dimensions of the image to be processed without degradation of accuracy. In our method, differential shape information from a 3-D reference shape is obtained by processing a straight-line-like light pattern projected in a camera view, which is a projection of a curved-line light pattern generated by the reference shape. Compared with straight-line light projections in most light-section methods, a light pattern projected on a measurement object can be captured in a narrower image region in our method, enabling high-speed processing for acquiring the 3-D shape with a higher dynamic range when the shape of the measurement object is cylindrical and its shape is given as a reference. Based on our method, we developed a real-time, high-frame-rate 3-D shape measurement system, which consists of a high-speed vision platform and an LCD projector. Its effectiveness was evaluated by showing experimental results for cylinder-shaped objects that were measured at 10,000 fps.

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