Direct-Mapping Cross-Interfaces Computed Tomography

Abstract

Abstract This work reports an optimized tomography method, termed Direct-Mapping Cross-Interfaces Computed Tomography (DMCICT), with enhanced calculation efficiency and accuracy for three-dimensional (3D) reconstruction in confined space. Confined-space tomography methods are designed to correct the image distortion on recorded target images caused by light refraction through optical walls, such as optical engine cylinders. However, past confined-space tomography methods have shortcomings in reconstruction accuracy and time efficiency, since they usually involve time-consuming iterations or numerical interpolation during calculating the mapping relationship from 3D measurement domain to 2D imaging planes. There, DMCICT is developed in this work to directly calculating the mapping relationship by performing reverse ray-tracings originated from imaging planes, then decide the intersection volumes with discretized measurement domain. Numerical and experimental validations of DMCICT are respectively performed based on multiple simulated phantoms and a two-branch laminar flame contained inside an optical cylinder. Compared to past confined-space reconstructions, DMCICT can reduce more than 50% of the computational time in majority of tested cases, while the reconstruction accuracy is also significantly enhanced. Moreover, DMCICT demonstrates the robustness under different spatial resolution conditions and presents solid endurance on measurement errors.