Reconstruction of 3D flame temperature and absorption coefficient field by the hybrid light-field imaging and laser extinction technique

Abstract

A hybrid method based on combining the light-field imaging and laser extinction techniques is proposed to reconstruct the 3D temperature and absorption coefficient fields in the pure absorbing flame. The inhomogeneous absorption coefficient distribution can be recovered based on the exit laser signals according to Beer-Lambert law firstly. According to the attained absorption coefficient distribution, the temperature field can be retrieved accurately with high efficiency by utilizing the light-field imaging technique. Besides, the influence of two types of measured signal noises, i.e. the laser signal noise and the light-field image signal noise, on the reconstructed quality have been investigated thoroughly. The Landweber method is adopted to solve the inverse analysis. All the results showed that the 3D temperature and absorption coefficient distribution can be reconstructed accurately and efficiently with different measurement noises, which proves the feasibility of the proposed method for the non-contact measurement of 3D temperature and absorption coefficient distributions of absorbing flame.