The effect of Anisotropy constant on Distribution of weight of diffuse-reflected photon packets on a hypothetical hemisphere-shaped detector


Aksel E. B. , Akin A.

Conference on Optical Interactions with Tissue and Cells XVII, San-Jose, Kostarika, 23 - 25 January 2006, cilt.6084

  • Cilt numarası: 6084
  • Doi Numarası: 10.1117/12.646443
  • Basıldığı Şehir: San-Jose
  • Basıldığı Ülke: Kostarika

Özet

In this work, preliminary results of a method to calculate anisotropy constant of scattering phase function (g) of a homogeneous. semi-infinite slab are shown. The method relies on measuring steady-state diffuse reflectance from the medium. In order to test the method, Monte-Carlo simulation of photon propagation in turbid media is utilized. Simulation depends on capturing diffuse-reflected photon packets which are injected perpendicularly by a point source in a continuous-wave manner. Photon packets are captured by a hemi-sphere like detector residing on the upper plane of the slab a few centimeters away from the source. The surface of the detector is divided into 120 sub-regions with equal area. Exit angles are converted into spherical coordinates. Therefore, the intersection of a particular photon packet with the detector surface is evaluated and the weight of photon packet is added to its corresponding sub-area. This process is repeated for all packets leaving the medium through the base of the hemisphere in each run. To evaluate the effect of anisotropy constant of the phase function on hemispheric weight accumulation the following simulations are performed. Optical properties of the medium are chosen as 10 cm(-1) for scattering coefficient, 0.1 cm(-1) for absorption coefficient, and 1.0 for refractive index. Detector is a non-scattering and non-absorbing medium whose refractive index is 1.0. Twenty millions of packets are used in the simulations. All optical properties except g are kept constant, while g is chosen to be 0.30, 0.50. 0.70, 0.75 and 0.80 for different runs.