Research on non-contact measurement algorithm of retrieving the parameters distribution of semi-transparent medium

For the semi-transparent media which only consider the absorption, emission and scattering attenuation characteristics, the outgoing radiative intensities at the boundary surface were simulated by the line-of-sight (LOS) method, which were served as input for the inverse analysis. The least-square QR decomposition (LSQR) algorithm was used to estimate the three dimensional temperature distributions of the semi-transparent media with known radiative properties. And the retrieval results show that the temperature distributions could be retrieved accurately even with noisy data. For the participating media with unknown radiative properties, a hybrid least-square QR decomposition (LSQR)-Stochastic Particle Swarm Optimization (LSQR-SPSO) algorithm was developed to estimate the 3-D temperature distributions and radiative properties (absorption coefficients and scattering coefficients) simultaneously. And the retrieval results show that the absorption coefficients, scattering coefficients and 3-D temperature distributions also could be retrieved accurately even with measurement errors. It was also found that the temperature field could be estimated more accurate than the radiative properties.