Improved light sectioning resolution by optimized thresholding

摘要

Abstract: A common approach to structured light illumination is light stripe projection onto a surface topology and then analyzing the lateral displacements of the reflected pattern to reconstruct the surface topology. A single spatial frequency of a light stripe pattern may be used to illuminate a relatively flat surface. In the case of rough surfaces, the surface topology is encoded with a sequence of light stripe patterns with successively higher spatial frequencies. In both approaches, the maximum resolution is limited by the maximum spatial frequency used. However, the tradeoff between SNR blurring and spatial frequency limits the final reconstruction accuracy. That is, as spatial frequency increases, the projection systems's blurring function causes the light stripes to be coupled thereby decreasing the SNR of the reflected image. We present both mathematical and numerical models for this phenomenon which indicates that by laterally moving the light stripe pattern across the surface and optimally thresholding the image, we can achieve measurement density and accuracy beyond that achieved by increasing the frequency of a stationary light stripe pattern. the numerical model to be calibrated will accept experimental data. Theoretical and numerical results will be compared with experimental results. !13