טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentIlizirov Grigory
SubjectPhotogrammetry Based on Imaging via Mirrors
DepartmentDepartment of Civil and Environmental Engineering
Supervisor Professor Sagi Filin
Full Thesis textFull thesis text - English Version


Abstract

The application of terrestrial photogrammetry for documentation and reconstruction of sites benefits from the ease of data collection, the ability to avoid physical contact with mapped objects, and the existence of well-established photogrammetric documentation methodologies. With current advances in imaging technology, where affordable digital cameras have high quality, using photogrammetry for mapping becomes even more relevant and wide spread. Nonetheless, photogrammetry application with of standard cameras is hindered by limited field of view, necessitating larger amount of images to be taken in order to perform mapping even of limited scenes. Extending the field of view offers advantages in covering larger spans within a single view. In this regard, when mirrors are incorporated into the imaging system the field of view can significantly be broadened.

Nonetheless, imaging scene via mirrors alters the collinearity principle, which states that an object point, its respective image point, and the cameras perspective center must all lie on a straight line. This fundamental principle, which stands at the core of most models, is altered by the reflection from the mirrors. Therefore, developments of appropriate mathematical models and theories for the application of photogrammetric concepts are required.

This thesis studies the influence of reflection geometry on the photogrammetric process and analyzes its theoretical aspects. It proposes a model for describing the geometric relations and for estimating the additional parameters involved. It shows that the information about the mirror location and shape is embedded in the object and image relation therefore a calibration of the camera and the mirror can be performed simultaneously. It also shows that for known mirror a collinearity law equivalent can be formed, and proposes a closed form model for planar and spherical mirrors.

Results show that the proposed models are stable and facilitate accuracy to a level of equivalent close-range photogrammetric practices.