Development of a direct-mapping tomography method to solve confined space problems with enhanced calculation efficiency

Abstract

This work reports an optimized tomography method, termed Direct-Mapping Cross-Interfaces Computed Tomography (DMCICT), with enhanced calculation e ciency and accuracy for three-dimensional (3D) reconstruction in con ned space. Con ned-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 con ned-space tomography methods have shortcomings in reconstruction accuracy and time e ciency, 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 ame contained inside an optical cylinder. Compared to past con ned-space reconstructions, DMCICT can reduce more than 50% of the computational time in majority of tested cases, while the reconstruction accuracy is also signi cantly enhanced. Moreover, DMCICT demonstrates the robustness under different spatial resolution conditions and presents solid endurance on measurement errors.