Geometric Calibration Based on a Simple Phantom for Multi-Lens Microscopic CT

In multi-lens microscopic cone-beam CT system, different resolutions can be achieved by tuning different objective lens with different magnifications, following the scan field of view (FOV) changed. By this multi-FOV/resolution acquisition strategy, many applications like truncation problem can be solved successfully. However, in order to achieve high-resolution image, the microscopic cone-beam CT system should comply with its geometrical restrictions accordingly, which are not only for that of conventional cone-beam system but also for that of multiple objective lens. Hence, compared with the existed cone-beam system calibration, a specific united calibration method is proposed in this paper. A set of geometrical parameters is presented, which can fully describe whole geometry of conventional cone-beam system as well as multi-lens. By taking use of projective data of circular trajectory of one single ball phantom, a cost function with the described arguments based on the projective lines of the phantom i...