We implement Monte Carlo-based parallel ray tracing to achieve quick irradiance evaluation for freeform lenses with nonuniform rational B-splines(NURBS)surfaces.We employ the inverse transform sampling method to sampl...We implement Monte Carlo-based parallel ray tracing to achieve quick irradiance evaluation for freeform lenses with nonuniform rational B-splines(NURBS)surfaces.We employ the inverse transform sampling method to sample rays uniformly from the Lambertian light source and adopt the analytical form of the B-spline basis function to achieve fast surface interpolation.When performing parallel calculations for the intersections between the rays and the NURBS surfaces,we propose a parameter transformation method to avoid the parameters escaping from the defined range in the iteration process.Simulation results of two complex picture-generating freeform lenses show that our method is fast and effective.展开更多
A simple method is proposed to design free- form surface for Lambertian extended source. In this method, it can take advantage of the designing method for point source via substituting each incident ray with a dynamic...A simple method is proposed to design free- form surface for Lambertian extended source. In this method, it can take advantage of the designing method for point source via substituting each incident ray with a dynamically calculated equivalent ray. For each facet on the freeform surface, the equivalent ray emits from the energy weighted average-emitting-position for the corre- sponding incident beam, and redirects into the direction which is determined by a source-to-target mapping. The results of the designing examples show that the light distributions＇ uniformities can be improved by this method, e.g., even the improvement of 59% can be achieved.展开更多
Based on nonimaging design method, uniform illuminance systems with LED source were developed to create a uniform illuminated circular region with a desired size in a screen at a prescribed place. By using ray-tracing...Based on nonimaging design method, uniform illuminance systems with LED source were developed to create a uniform illuminated circular region with a desired size in a screen at a prescribed place. By using ray-tracing software based on Monte-Carlo method, the simulation results show that in the illuminated region the luminous uniformity is higher than 90%.展开更多
基金supported by the National Key Research and Development Program of China(No.2017YFA0701200)the National Natural Science Foundation of China(No.11704030)the CAAI-Huawei MindSpore Open Fund(No.CAAIXSJLJJ-2021-014A)。
文摘We implement Monte Carlo-based parallel ray tracing to achieve quick irradiance evaluation for freeform lenses with nonuniform rational B-splines(NURBS)surfaces.We employ the inverse transform sampling method to sample rays uniformly from the Lambertian light source and adopt the analytical form of the B-spline basis function to achieve fast surface interpolation.When performing parallel calculations for the intersections between the rays and the NURBS surfaces,we propose a parameter transformation method to avoid the parameters escaping from the defined range in the iteration process.Simulation results of two complex picture-generating freeform lenses show that our method is fast and effective.
基金This work was supported by the National Key Basic Research Program of China （Nos. 2015CB351900, 2011CB301902 and 2011CB301903）, the National Key Technology Research and Development Program of the Ministry of Science and Technology of China （No. 2012BAE01B03）, the Science and Technology Planning Project of Guangdong Province （No. 2011A081301003）, the Opened Fund of the State Key Laboratory on Integrated Optoelectronics （No. IOSKL2012KF09）, the High Technology Research and Development Program of China （Nos. 2011AA03A112, 2011AA03A106 and 2011AA03A105）, the National Natural Science Foundation of China （Grant Nos. 61307024, 61176015 and 61176059）.
文摘A simple method is proposed to design free- form surface for Lambertian extended source. In this method, it can take advantage of the designing method for point source via substituting each incident ray with a dynamically calculated equivalent ray. For each facet on the freeform surface, the equivalent ray emits from the energy weighted average-emitting-position for the corre- sponding incident beam, and redirects into the direction which is determined by a source-to-target mapping. The results of the designing examples show that the light distributions＇ uniformities can be improved by this method, e.g., even the improvement of 59% can be achieved.
文摘Based on nonimaging design method, uniform illuminance systems with LED source were developed to create a uniform illuminated circular region with a desired size in a screen at a prescribed place. By using ray-tracing software based on Monte-Carlo method, the simulation results show that in the illuminated region the luminous uniformity is higher than 90%.
