【摘要】 在大气或流动介质中的折射率分布是无规则非均匀的,由于流动和温度变化的影响,无法用通常的梯度折射率公式来描述。提出采用自适应网格方法来描述无规则非均匀折射率场,将数据以动态八叉树结构存放在内存中,给出了网格划分的折射率判据和折射率梯度判据,并采用插值法来计算光线传播路径上的折射率和折射率梯度。以一种可以用公式描述的梯度折射率棒为例,在折射率阈值为0.005、折射率梯度阈值为0.0005的条件下,建立了自适应网格并求出了一些位置处的折射率及其梯度,计算结果的均方根误差小于7×10-5,可以用于光线追迹。更多还原

【Abstract】 The refractive index field in atmosphere or fluid medium is irregular and inhomogeneous,and cannot be described by a usual gradient index formula due to the influence of flowage and change of temperature.The self-adaptive grid is used for describing the irregular inhomogeneous refractive index field,and the refractive index data are stored in RAM as a dynamic octa-tree,The criterion of grid division for refractive index and its gradient are given and the interpolation method is used for calculating the refractive index and its gradient at positions along the ray trace trajectory.A gradient index(GRIN) rod,in which the refractive index can be described by a formula,is also analyzed as an example.The self-adaptive grid is created and the refractive indexes and its gradient at some positions with high accuracy are output.The RMS error is under 7×10-5 and can be used for ray tracing.更多还原