Environment Effects at Phantom-Based X-Ray Pose Measurements

abstract

Image-based pose measurements relative to phantoms are used for various applications. Some examples are: tracking, registration or calibration. If highly precise measurements are needed, even changes of environment factors influence the measurements. This work evaluates how humidity and room temperature affect an image based pose measurements using a phantom. The pose measurement is used for the specific use case of an absolute accurate calibration of a C-arm X-ray system. However, the results are transferable to other applications, too. We describe the effects on different measurement parameters and experimentally evaluate the imprecisions caused by water absorption and thermal expansion of the phantom. The real world results show, that it is needed to monitor the environment effects if measurement precisions in the submillimeter scale are necessary.