Demonstration of 3D computed tomography of chemiluminescence with a restricted field of view

Abstract

Three-dimensional imaging techniques have experienced a surge in research interest during the past few years due to advancements in both hardware, i.e., the sensor arrays and data acquisition systems, and new imaging concepts, such as light field imaging and compressed sensing. Computed tomography of chemiluminescence (CTC) is an intriguing technique for combustion diagnostics due to its ease of implementation, as no excitation source is required in measurements. It has been applied extensively for the retrieval of intermediate species such as CH^*/OH^*, from which the flame topology can be obtained. However, all previous demonstrations or applications were performed under the assumption that a complete field of view is available for all projections. However, this prerequisite cannot be guaranteed for some practical scenarios, such as engine measurements, in which optical access is extremely limited and a portion of the field of view is unavoidably blocked, especially when a considerable number of projections are required. This work aims to develop an improved CTC modality that can handle projections with a restricted field of view, and to suggest the best strategy for tomographic reconstruction under such experimental conditions. Although this technique is discussed under the context of combustion diagnostics, it can also be useful and adapted for other tomographic areas, such as biomedical imaging.