Towards a Micron-level Line Structured Light

Line structured light is a classic and popular approach for 3D object measurement. However, in many prior works, it is only evaluated on the application level, and researchers may ignore comparisons between measured values and highly accurate labels. The calibration accuracy may also not be the primary factor for specific high-precision measurement tasks: the calibration method is sophisticated and only responsible for determining fixed transformations between the camera and the laser plane. In this paper, we propose a semantic centroid method to extract laser lines in various gray values accurately, and several other factors are analyzed when measuring object thicknesses. On a customized dataset sampled from gauge blocks with ground-truth thicknesses, under strict conditions, our line structured light obtains measurement errors at the micron level.