光学学报, 2019, 39 (7): 0709001, 网络出版: 2019-07-16
一种新的正交扫描多视投影计算全息图生成方法 下载: 1056次
Computer-Generated Holograms with Improved Orthogonal Scanning Multi-view Projections
全息 多视投影 正交扫描 圆形扫描 傅里叶频谱 hologram multi-view projection orthogonal scanning circular scanning Fourier spectrum
摘要
提出一种新的正交扫描多视投影计算全息图生成方法。该方法基于推导出的物体三维傅里叶频谱抽样统一模型及其误差分析,设置角度参数,从正交扫描投影图中模拟获得特定角度圆形扫描下的投影图频谱采样圆,并按“θ 角(扫描视角)小者优先”准则确定重叠位置的频谱采样信息,从而提高正交投影图频谱利用效率;从理想采样点与其取整点在频谱信息一致性、空间邻近程度的相互关系出发,设置理想采样点所在频域格网点权重值,并以之为基础自适应选取频谱信息一致性较高的格网点作为实际采样点,从而在投影图频谱充分采样和背景噪声引入之间取得平衡,以获得最优的物体三维傅里叶频谱。针对虚拟三维模型的正交扫描多视投影计算全息实验结果表明,所提方法可明显改善所生成的全息图再现像视觉质量,其再现像信噪比不仅在相同投影图数量下显著优于传统正交、圆形扫描方法,并且在冗余采样条件下,投影图数量减少为原来的1/2时,所提方法所生成的全息图再现像信噪比也优于传统正交、圆形扫描方法,因此所提方法具有较高的应用价值。
Abstract
This paper presents a novel approach to generate computer-generated holograms (CGHs) with orthogonal scanning multi-view projections. An unified object three-dimensional Fourier spectrum sampling model is established, and based on its error analysis, the spectrum sampling circle of a circular scanning projection image at a specific angle θ can be simulated from a traditional orthogonal scanning projection image; then, the principle of "smaller θ (view angle of scanning) wins all" is adopted to determine the spectrum sampling information for overlapped positions so as to improve the spectrum utilization efficiency of orthogonal scanning projection image. Starting from the relationship between the ideal sampling point and its integration points in the consistency of spectrum information and the degree of spatial proximity, we set the weights of frequency-domain grid points where the ideal sampling points are located. Based on these weights, grid points with high consistency of spectrum information are selected adaptively as the actual sampling points, thereby achieving a balance between the sufficient sampling of projection spectrum and the introduction of background noise to obtain the optimal object three-dimensional Fourier spectrum. Experimental results of CGH with the orthogonal scanning multi-view projection for a virtual three-dimensional model show that the visual quality of the reconstructed hologram by the proposed method is notably improved. The signal-to-noise ratio of the reconstructed hologram is significantly better than that of traditional orthogonal and circular scanning methods under the same number of projected images; in addition, the signal-to-noise ratio of the reconstructed hologram implemented with a redundant sampling operation by the proposed method is also better than that of the traditional orthogonal method even when the number of projected images is reduced by one time. Therefore, the proposed method has great values both on theory and practice.
吴军, 王冰洋, 彭智勇. 一种新的正交扫描多视投影计算全息图生成方法[J]. 光学学报, 2019, 39(7): 0709001. Jun Wu, Bingyang Wang, Zhiyong Peng. Computer-Generated Holograms with Improved Orthogonal Scanning Multi-view Projections[J]. Acta Optica Sinica, 2019, 39(7): 0709001.