Flame emission tomography based on finite element basis and adjustable mask

Abstract

Flame emission tomography is a promising tool for combustion diagnostics. Up to now, this technique relies on the assumption that the distribution within a voxel is uniform. Such an assumption suffers from a large gradient between adjacent voxels and the loss of information within the voxel. Hence, this work aims to develop a method based on the finite element basis to address the above shortcomings. From the reconstruction side, an adjustable mask is developed to suppress the artifacts and speed up reconstruction. Both simulative and experimental studies have been designed and conducted. The simulative results show that the finite element basis can decrease the reconstruction errors (defined as normalized 2-norm difference) from 0.616 to 0.241 and 0.386 to 0.203 by the algebraic reconstruction technique for two representative flame phantoms. The adjustable mask can decrease the reconstruction error for both bases, especially under low voxel resolution. The experimental results show that the predicted projection error of the finite element basis with the adjustable mask is decreased by 57% compared with that of the uniform voxel basis with the fixed mask when the voxel resolution is 16 × 16 × 20. Furthermore, the finite element basis can generate better reconstructions with fewer voxels. Both simulative and experimental studies suggested the superiority of the finite element basis with the adjustable mask.