二步法大景深反射全息图

Two-Step Large Scene Reflection Holograms

以开拓反射全息图的景深表达能力为目的,从反射全息图的共轭物像关系出发,利用反射全息图的均匀介质耦合波理论和布拉格条件,对其白光再现像模糊作了具体的分析和讨论,得到色模糊和线模糊的表达式。指出反射全息图上不同各点对任意白光再现像点的色模糊和线迷糊的影响均存在差异,给出反射全息图白光再现像的景深表达式。实验利用二步法制作了一张景深为83 cm的反射全息图,与大景深彩虹全息图再现像相比,其再现像的立体感更加强烈。理论分析和实验结果表明,光源的再现角度和观察距离对反射全息图的再现像景深大小影响显著。在再现光垂直于反射全息图平面照明情况下,反射全息图具有最好的景深表达能力。

To exploit the expressive ability of depth of field of reflection holograms according to the relationship between object and conjugate image, and using the uniform coupled-wave theory and the Bragg condition, the image blur of reflection hologram which was caused by reconstruction with white light source, was analyzed and discussed concretely, so the expressions of the color blur and linear blur were achieved. Such a difference was pointed out.. when the reflection hologram was constructed by white light source, the color blurs and linear blurs caused by different dots on the reflection hologram, have different effects for the same construction image point. The expression about the depth of field of reflection hologram was advanced. A two-step large scene depth reflection hologram which is deep as 83 centimeters was obtained in experiment. Compared with large depth rainbow hologram, the three-dimensional effect of the reconstruction image is stronger. The theoretical analysis and the experimental result showed that, the depth of field of reflection hologram＇s reconstruction image will be affected markedly by reconstructing angle and the watching distance. When the reflection hologram was reconstructed vertically, it has the most ability to express it＇s depth of field.