상세정보
학술지
Modeling of diffuse-diffuse photon coupling via a nonscattering region: a comparative study
- 발행일
- 200406
- 출처
- Applied Optics, v.43 no.18, pp.3640-3655
- ISSN
- 1559-128X
- 출판사
- Optical Society of America (OSA)
- 협약과제
- 03MB3500, e-Health 구현을 위한 바이오 정보통신 기술, 김윤태
- 초록
- It is well established that diffusion approximation is valid for light propagation in highly scattering media, but it breaks down in nonscattering regions. The previous methods that manipulate nonscattering regions are essentially boundary-to-boundary coupling (BBC) methods through a nonscattering void region based on the radiosity theory. We present a boundary-to-interior coupling (BIC) method. BIC is based on the fact that the collimated pencil beam incident on the medium can be replaced by an isotropic point source positioned at one reduced scattering length inside the medium from an illuminated point. A similar replacement is possible for the nondiffuse lights that enter the diffuse medium through the void, and it is formulated as the BIG method. We implemented both coupling methods using the finite element method (FEM) and tested for the circle with a void gap and for a four-layer adult head model. For mean time of flight, the BIC shows better agreement with Monte Carlo (MC) simulation results than BBC. For intensity, BIC shows a comparable match with MC data compared with that of BBC. The effect of absorption of the clear layer in the adult head model was investigated. Both mean time and intensity decrease as absorption of the clear layer increases. © 2004 Optical Society of America.
- KSP 제안 키워드
- Boundary coupling, Clear layer, Coupling method, Diffusion approximation, Finite Element Method(FEM), Four-layer, Light propagation, Monte Carlo (MC) Simulation, Pencil beam, Region-based, Scattering length