A performance test for a fringe projection scanner in various ambient light conditions

Optical triangulation based scanners have been widely used in industry, mainly for reverse engineering applications and freeform inspection tasks. Error contributions of these optical scanners include many influencing factors like surface quality and material properties of measurand, orientation and scan depth of sensors, ambient light changes, etc. This paper presents a performance evaluation test for a commercially available structured light scanner, under different ambient light conditions. The freeform reference standard developed by National Physical Laboratory is used to identify the influence of ambient light changes to the measurement accuracy

Imaging solutions for harsh environments

This paper presents a quantitative assessment of uncertainty for the stereo calibration at different cameras angle and control object 3D reconstruction. Stereo-photogrammetry with high resolution commercially available digital cameras is applied to deliver a 3D data from a pair of 2D images. The main goal of the project is the reconstruction of the 3D model from the images obtained underwater in a high vibration manufacturing environment. The crucial step in obtaining high accuracy 3D data is stereo-rig calibration. Robust camera calibration is a critical step in 3D reconstructions in order to extract precise quantitative measurements from 2D images. Two AV 6600 monochrome 29 Megapixels GigE cameras were calibrated at four different angles to ensure that the angle of the stereo rig and variation in image contrast would not influence significantly the final results. All the images were undertaken in the high vibration manufacturing environment. It was shown that calibration of the cameras set at the angle of 15o reduces significantly 3D reconstruction accuracy. However, it does not influence reprojection error, which is less than 0.5 pixels