Method for expanding the field-of-view of micro-CT imaging using array micro-focus X-ray source.

Micro-computed tomography (micro-CT) is a critical high-resolution, non-destructive testing technique. However, its field-of-view (FOV) is constrained by the detector size, which limits the ability to perform high-resolution imaging of larger objects. To overcome this limitation, we developed a method for expanding the FOV of micro-CT imaging using an array micro-focus X-ray source based on electron beam scanning (EBMCT). This innovative approach expands the FOV by allowing X-rays to traverse different regions of the object through focal array scanning. Due to the unique scanning methodology of EBMCT, the resulting projections exhibits redundancy and truncation issues. For this reason, we propose a weighting distribution strategy based on trigonometric functions to smooth the projections, effectively mitigating the effects of redundancy and truncation on the reconstructed images. Furthermore, by combining the geometric structure of EBMCT and the weighting function, we derive a two-dimensional analytical reconstruction algorithm (Weighted multi-sources filtering back-projection, w-MSFBP) and a three-dimensional approximate reconstruction algorithm (Weighted multi-sources Feldkamp-Davis-Kress, w-MSFDK) for EBMCT reconstruction. Simulation and physical experiment results show that EBMCT can expand the FOV by more than two times while maintaining high resolution. Additionally, both the w-MSFBP and w-MSFDK algorithms accurately reconstruct two-dimensional and three-dimensional structures of the scanned objects. By effectively expanding the FOV of micro-CT, EBMCT provides valuable insights for the research and design of large FOV micro-CT systems.