Optimization of geometric models and development of calibration strategies for an all-reflective camera system

Project title

All-reflective optics for multispectral image acquisition in photogrammetric applications

Funding

German Research Foundation (DFG)

Motivation

Conventional refractive systems have a significant loss of image quality and geometric accuracy due to the chromatic aberration of lenses. This fact is important especially for photogrammetric applications that require imaging a wide spectral range. Those chromatic aberration problems can be completely avoided in all-reflective optical systems.

Aims and tasks

The aim of the project is the design and verification of an all-reflective multispectral high resolution wide-angle camera system for the application in photogrammetric measurement tasks at a high and at the highest level of accuracy. The all-reflective unobscured optical system with ultra precision optical components shall reach a new quality of reflective optics in this field.

Design of an all-reflective unobscured multispectral high resolution wide-angle camera system for the application in photogrammetric measurement tasks at a high and at the highest level of accuracy
Realization of a demonstration system
Extension of the collinearity condition by a specific additional parameter set and a finite elements approach
Development of calibration strategies for the reliable estimation of the model parameters

Results

At first we developed three demonstrators with different fixed focal lengths, each equipped with a RGB sensor. The large asymmetric geometric image distortion can be corrected with the developed geometric camera model. Based on these preliminary investigations we designed an all-reflective multispectral camera system and built up a prototype.