Non-contact 3D Measurement of Freeform Reflective Surface

Abstract

AbstractNon-contact 3D shape measurement has been widely studied and applied to many fields of science and engineering owing to high speed, high accuracy, and simple implementation. However, the measurement system still poses improper acquisition of optical signal when surfaces with high reflectivity are scanned. This paper proposes a new and effective approach to solve the problem of shiny mechanical surface measurement. The appropriate exposure time for the surface measurement is indicated through image intensity histogram analysis. The appropriate exposure times in each region of the histogram are determined. Then, point clouds are merged at appropriate exposure times to obtain a good quality point cloud, avoiding the saturation region on the CCD. Profile parts of two different aluminum surfaces are measured fast and accurately using single exposure time and proposed solution. Experimental results prove that the proposed technique can inspect the 3D surface of the mechanical parts with high surface reflectivity.Keywords3D shape measurementFringe projectionShiny surfaceHigh dynamic range