title: Multi-directional 3D flame chemiluminescence tomography based on lens imaging.
abstract: Flame chemiluminescence tomography (FCT) has been widely used in flame diagnostics for three-dimensional (3D), spatially resolved measurements of instantaneous flame geometry and, to some extent, of species concentrations. However, in most studies, tomographic reconstructions are based on a traditional parallel projection model. Due to the light collection characteristics of a lens, a parallel projection model is not appropriate for the practical optical setups that are used for emission imaging, particularly at small F-numbers. Taking the light collection effect of the lens into account, this Letter establishes a complete and novel tomographic theory for a multi-directional tomography system consisting of a lens and CCD cameras. A modified camera calibration method is presented first. It determines the exact spatial locations and intrinsic parameters of the cameras. A 3D projection model based on the lens imaging theory is then proposed and integrated into the multiplicative algebraic reconstruction technique (MART). The new approach is demonstrated with a 12-camera system that is used to reconstruct the emission field of a propane flame, thereby resolving space and time.
authors.forename: Jia
authors.initials: J
authors.lastname: Wang
authors.forename: Yang
authors.initials: Y
authors.lastname: Song
authors.forename: Zhen-hua
authors.initials: ZH
authors.lastname: Li
authors.forename: Andreas
authors.initials: A
authors.lastname: Kempf
authors.forename: An-zhi
authors.initials: AZ
authors.lastname: He