基于分层技术的三维物体全息图的快速算法

Fast algorithm for generating hologram of a 3D object by employing connection between layers

提出了一种计算三维物体全息(CGH)图的快速算法。在传统的相干光线追迹(CRT)算法中,将三维物体分成很多层,每一层看作是一系列点源的集合,通过计算机模拟每一层上所有点光源光线的传播再与参考光干涉得到物体的CGH。在本文提出的算法中,假设物体的深度相对传播距离非常小,只需要计算第1层和全息面之间的倾斜因子,其余面和全息面之间的倾斜因子可以通过一个非常简单的关系得到。因此,本文算法计算量得到了简化,计算速度比传统的CRT算法快约6倍。同时光学重建了CGH,计算表明,本文快速算法光学重建像的质量和传统算法有很好的吻合。

An approximate method for generating computer-generated hologram （CGH） of a 3D object with speed 6 times faster than the conventional algorithm is presented. In the conventional coherent ray tracing （CRT） algorithm,a 3D object is sliced into many layers and treated as the collection of self-illu- minated point light sources. The process of light ray propagating from every point of object to all the points on the hologram plane and interferred with the reference beam to form a CGH is simulated. In our proposed method,under the assumption that the depth of 3D object is much smaller than the recording distance,we just need to calculate the oblique distance between the first layer and the hologram plane, and then the oblique distances from the other layers to hologram plane can be obtained from their simple relation, thus the computational time is much reduced. The CGH is optically reconstructed and the quali- ty of the reconstructed image is as good as that from the conventional algorithm.