火焰辐射光场成像光线采样特性

为了研究全光相机对火焰等半透明介质的光场采样并优化全光相机的参数,基于近轴光学,建立了全光相机的逆向光线追迹模型。在此基础上,针对弥散介质沿采集方向的半透明特性,提出了像素采样锥形角以及物方采样角度等评价光线角度采样的性能指标,据此分析了全光相机像素和微透镜的位置对光场采样特性的影响,以及全光相机光学参数变化对光线方向采样性能的影响。结果表明:采集火焰辐射光场时,较小的微透镜直径有利于提高光场采样的单方向性,并减小主镜头入瞳直径,而较小的主镜头焦距有利于增大物方采样角度。

Characterization of ray sampling for flame radiation in light field imaging

To investigate the radiation sampling of the translucent media and optimize the parameters of a plenoptic camera,a backward ray tracing model is established based on the paraxial approximation in this pa-per. Considering the integrating properties along the sampling path of the translucent media,several indices for evaluating the angular sampling are then proposed such as cone angle of a single pixel and sampling angel of object side. The effects of the positions of the pixels and micro lenses of the plenoptic camera on the radia-tion sampling and the effects of the optical parameters of the plenoptic camera on ray direction sampling per-formance are analyzed. The results indicate that,for the light field sampling on flame radiation,a smaller di-ameter of the micro lens is useful for improving the accuracy of radiation sampling in certain direction and de-creasing the size of main lens aperture. Moreover,smaller focal length of main lens is advantageous for impro-ving the sampling angle of object side.