Abstract: A three-dimensional (3D) terrain reconstruction method for a scoured area around bridge pier foundation based on a mechanical scanned imaging sonar includes scanning an overall terrain of a scoured area around bridge pier foundation with a sonar from different azimuths to acquire n sonar images of a foundation scouring terrain; intercepting multiple analysis sections from each of acquired sonar images at a same distance; extracting key parameters of upper and lower edges on a terrain imaging strip in each of the analysis sections in the image, and transforming extracted parameters to a 3D space, a fan-shaped beam surface of the sonar being represented with a fan-shaped arc; recognizing a scour terrain profile in the analysis section; recognizing terrain profiles one by one, and respectively extracting spatially scattered 3D coordinate data; and performing interpolation and fitting on the spatially scattered data, thus implementing 3D reconstruction for the foundation scouring terrain.

Abstract: A three-dimensional (3D) terrain reconstruction method for a scoured area around bridge pier foundation based on a mechanical scanned imaging sonar includes scanning an overall terrain of a scoured area around bridge pier foundation with a sonar from different azimuths to acquire n sonar images of a foundation scouring terrain; intercepting multiple analysis sections from each of acquired sonar images at a same distance; extracting key parameters of upper and lower edges on a terrain imaging strip in each of the analysis sections in the image, and transforming extracted parameters to a 3D space, a fan-shaped beam surface of the sonar being represented with a fan-shaped arc; recognizing a scour terrain profile in the analysis section; recognizing terrain profiles one by one, and respectively extracting spatially scattered 3D coordinate data; and performing interpolation and fitting on the spatially scattered data, thus implementing 3D reconstruction for the foundation scouring terrain.