Spherical acquisition trajectories for X-ray computed tomography with a robotic sample holder

TL;DR

This paper introduces a robotic system for executing arbitrary spherical trajectories in X-ray CT, improving reconstruction quality and coverage over traditional methods, and enabling more flexible, efficient imaging with reduced scan times and radiation exposure.

Contribution

The paper presents a novel robotic sample holder system with optimized path planning for spherical trajectories in X-ray CT, enhancing image quality and trajectory coverage.

Findings

Achieved nearly 82% of all possible rotations with the robotic system.

Improved reconstruction quality over conventional circular trajectories.

Demonstrated system's potential for flexible, task-specific imaging trajectories.

Abstract

This work presents methods for the seamless execution of arbitrary spherical trajectories with a seven-degree-of-freedom robotic arm as a sample holder. The sample holder is integrated into an existing X-ray computed tomography setup. We optimized the path planning and robot control algorithms for the seamless execution of spherical trajectories. A precision-manufactured sample holder part is attached to the robotic arm for the calibration procedure. Different designs of this part are tested and compared to each other for optimal coverage of trajectories and reconstruction image quality. We present experimental results with the robotic sample holder where a sample measurement on a spherical trajectory achieves improved reconstruction quality compared to a conventional circular trajectory. Our results demonstrate the superiority of the discussed system as it outperforms single-axis systems by reaching nearly 82\% of all possible rotations. The proposed system is a step towards higher image reconstruction quality in flexible X-ray CT systems. It will enable reduced scan times and radiation dose exposure with task-specific trajectories in the future, as it can capture information from various sample angles.