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.