International Archives of Photogrammetry and Remote Sensing. Vol. XXXII, Part 6. Bandung-lndonesia 1999
57
PROCEDURES OF CORRECTION OF THE GEOMETRY DISTORSIONS
FOR DIGITAL IMAGES
F. Barison A. Guamieri, A. Vettore
Dip. Costruzioni e Trasporti - Università di Padova - Italy Dip. Territorio TESAF - Università’ di Padova - Italy
Via Marzolo 9-35100 Padova AGRIPOLIS - Statale Romea 16
35020 Legnaro (Padova)
Phone +39-049-8275580 , fax +39-049-8372713
e-mail: vettoan@ux 1. unipd, i t
ABSTRACT
Since a few years digital fotocameras have widely spread on the market, principally because of their price, quality image
improvement and easy of use. In order to extract from these digital images reliable 3D informations regarding objects position and
dimension, both the exact knowledge about perspective and dimensional relations between image and scene, and the knowledge
about the geo-metric distortions parameters are needed.
Therefore, the aim of this work was to develope an alternative method to estimate the parameters of the major forms of geometric
distortions, i.e. radial, tangential, decentering and thin-prism. The proposed method, based on Tsai calibration algorithm and
Leveberg-Marquardt non linear optimi-zation procedure, starts with a first estimate of inner and exterior orientation parameters in
absence of distortion, taking into account only center image points. Then a non linear estimate of all digital camera parameters is
carried out, taking into account all image points in order to compute the geo-metric distortions as well.
The method has been implemented in such a way to allow a full camera calibration or a compu-tation of the exterior orientation
parameters only, using inner orientation and distortion parameters determined from previous full calibration. This approach can be
useful if only an estimate of new targets positions is required, in which the inner and distortion parameters are already given.
