Speckle Based Pose Estimation for 3D Measurement of the Feature-less Environment by Two Cameras

In this research, we propose the 3D measurement system combining structured light and speckle based pose estimation by introducing two different setting cameras. The proposed system consists of two lasers, spot laser and line laser, and two cameras, with and without lens, which can obtain both focused and defocused images at once. Local shapes are measured using focused images by a structured light method. 3D positions of points projected by laser are calculated by triangulation. Pose changes are estimated from speckle information using defocused images. Displacements of speckle patterns are detected as optical flow by Phase Only Correlation (POC) method. Pose changes are estimated from speckle displacements by solving equations derived from the physical nature of speckle. The target shape as a whole is reconstructed by integrating local shapes into common coordinates using estimated pose changes. In the experiment, the texture-less flat board was measured with motion. From the experimental results, it is confirmed that the shape of the board was reconstructed correctly by the proposed 3D measurement system.