Focal shifts in diffractive Fresnel lens are measured. The result is closer to the theory given by generalized eikonal.
实验测定了波带板的焦移，接近与广义程函数理论。
2
More practical ray tracing methods currently include the wavefront method, the shortest path method, the travel time epenthesis method, the eikonal equation finite difference method, etc.
当前实用性较强的射线追踪方法，包括波前法，最短路径法，走时插值法，程函方程有限差分法等。
3
A new technique is given here, which combines partial algorithm with scanning algorithm and obtains wave arrival times by solving eikonal equation with the use of finite difference method.