A Bivariate Thin-Plate Adaptive Smoothing Spline (BTPASS) to reduce noise in photogrammetric digital surface models Pascal Sirguey 10.17608/k6.auckland.9870014.v1 https://auckland.figshare.com/articles/conference_contribution/A_Bivariate_Thin-Plate_Adaptive_Smoothing_Spline_BTPASS_to_reduce_noise_in_photogrammetric_digital_surface_models/9870014 <div>Photogrammetric surface restitution has considerably improved, with advances in stereo-matching algorithms allowing dense and relatively clean digital surface models to be created from triangulated stereo-imagery. Nevertheless, application to scanned historical analogue imagery in</div><div>challenging contrast is exposed to noise due to fi lm grain. Restitution can produce ancillary information about the intersection error from homologous rays that measure the quality of the match. This paper proposes and demonstrates a post-processing method to filter the resulting surface with thin-plate smoothing spline. The level of smoothing is locally adaptive to allow the topography to be preserved when correctly restituted, while signi ficantly reducing noise on</div><div>low-contrast areas.</div> 2019-09-18 02:26:32 Digital Surface Model photogrammetry filtering smoothing spline ray intersection error Geospatial Information Systems