UNDERWATER COMPARISON OF WAND AND 2D PLANE NONLINEAR CAMERA CALIBRATION METHODS

  • Amanda P. Silvatti
  • Thiago Telles
  • Fábio A. S. Dias
  • Pietro Cerveri
  • Ricardo M. L. Barros
Keywords: nonlinear camera calibration, 3D underwater analysis

Abstract

The purpose of this study was to compare two nonlinear camera calibration methods for 3D underwater motion analysis. The DVideo kinematic analysis system was used for underwater online data acquisition. The system consisted of two gen-locked Basler cameras working at 100Hz, with wide angle lenses that were enclosed in housings. The accuracy of both methods was compared in a dynamic rigid bar test. The mean absolute errors were 1.16mm for wand calibration, 1.20mm for 2D plane calibration using 8 control points and 0.73mm for 2D plane calibration using 16 control points. The results of both nonlinear camera calibration methods provided better underwater accuracy than all previous papers reported in literature. Both methods provided similar and highly accurate results, providing promising alternatives for underwater 3D motion analysis.