Premium
Photogrammetric Techniques for Voxel‐Based Flow Velocity Field Measurement
Author(s) -
Westfeld Patrick,
Maas HansGerd
Publication year - 2011
Publication title -
the photogrammetric record
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.638
H-Index - 51
eISSN - 1477-9730
pISSN - 0031-868X
DOI - 10.1111/j.1477-9730.2011.00656.x
Subject(s) - cuboid , voxel , computer science , computer vision , artificial intelligence , tracking (education) , data set , calibration , affine transformation , 3d reconstruction , mathematics , geometry , psychology , pedagogy , statistics
The paper presents improved photogrammetric techniques for the determination of 3D flow velocity fields with the goal of optimising the performance, efficiency and flexibility of the method. This includes a multi‐camera system configuration and calibration, as well as approaches for volumetric reconstruction. The result of the volumetric reconstruction process is a time‐resolved, voxel‐space representation of tracer particles marking a flow. Using a high‐speed camera, a typical data‐set consists of 1000 volumetric data‐sets per second, each with 1000 × 1000 × 300 voxels. 3D tracking in the time‐resolved voxel data is performed by 3D least squares tracking, determining 12 parameters of a 3D affine transformation between cuboids in successive voxel data‐sets. Besides the cuboid translation, these parameters also include information on the shear tensor of each cuboid. The tomographic reconstruction methods and the cuboid tracking have been implemented and validated with both simulated and real data in an experimental set‐up of a vortex ring in a water tank.