A concept of divergence angle of light beams (DALB) is proposed to analyze the depth of field (DOF) of a 3D light-field display system. The mathematical model between DOF and DALB is established, and the conclusion that DOF and DALB are inversely proportional is drawn. To reduce DALB and generate clear depth perception, a triple composite aspheric lens structure with a viewing angle of 100° is designed and experimentally demonstrated. The DALB-constrained 3D light-field display system significantly improves the clarity of 3D images and also performs well in imaging at a 3D scene with a DOF over 30 cm.

针对当前3D光场手势交互存在识别率低、识别速度慢、深度学习网络需要较多数据样本的问题，本文提出了一种基于小样本手部关键点的多层感知器（Multi-Layer Perceptron，MLP）网络提升3D光场交互准确度方法，识别速度达到毫秒级。在手部关键点采集过程中，从不同位置采集得到的同一种手势关键点三维数据存在显著差异。为了消除差异，本文提出在同一右手笛卡尔坐标系下，通过位移和罗德里格旋转公式对简化后的手势模型进行位姿变换，将同一种手势归一化。一个MLP神经网络被用来从归一化后的手部关键点跳变关系中提取手部特征。实验结果表明，本文提出的方法对3D光场交互中的简单手势识别率为95%以上，对复杂手势的识别率为90%以上。与此同时，该方法在小样本数据集训练下表现出优秀的性能，能够满足精确和快速手势识别的要求。最后，本文展示了一种将所提出的方法成功应用于3D光场交互的场景。

In the integral imaging light field display, the introduction of a diffractive optical element (DOE) can solve the problem of limited depth of field of the traditional lens. However, the strong aberration of the DOE significantly reduces the final display quality. Thus, herein, an end-to-end joint optimization method for optimizing DOE and aberration correction is proposed. The DOE model is established using thickness as the variable, and a deep learning network is built to preprocess the composite image loaded on the display panel. The simulation results show that the peak signal to noise ratio value of the optimized image increases by 8 dB, which confirms that the end-to-end joint optimization method can effectively reduce the aberration problem.

在裸眼3D显示中，传统的多视点采集方式为均匀采集。研究表明，因柱透镜光栅存在畸变，所以显示器构建的视点分布并不均匀，进而导致显示器视点和采集视点不匹配，产生了视点图像错位、透视关系错误等问题，影响最终的观看体验。针对上述问题，本文提出了一种多视点图像分布校正方案，该方案由一种视点筛选算法和中间视点生成网络构成：结合空间视点真实分布规律，针对均匀采集的多视点图像进行视点筛选，以指导中间视点预测网络生成对应位置的虚拟视点，使之匹配显示器构建视点位置。实验证明该方案为显示器视点填充了正确的视差图，有效地解决了显示器空间视点和采集视点的位置不匹配问题，提升了光栅立体显示器的观看质量。

基于视点分段式体像素的桌面光场显示系统具有正面观看视区以及100°超大视角，能够显示具有全视差的高质量三维图像。但是，该系统还存在所构建的视点在空间分布不均匀的问题，观看视区中间区域视点分布密集，两边区域视点分布稀疏，使得显示的三维图像出现透视关系不正确以及视点间的串扰等问题，影响显示质量。本文通过对系统视点的构建过程进行分析，发现造成视点分布不均匀问题的原因是系统采用的柱透镜存在像差，导致出射光线无法会聚于一点，而是形成一个弥散斑。因而，为了均匀系统视点分布，本文提出了采用对透镜进行光学优化的方法以减小像差，并设计了一种非球面透镜。最终通过实验验证了方法的可行性，系统视点分布的均匀度由39.32%提升至98.39%，显示图像透视关系不正确以及视点间的串扰等问题得到了有效改善。

3D光场显示技术因具有较大的观看视角、密集的观看视点而被研究学者们关注。分辨率是3D光场显示技术的一个重要参数，提升分辨率的方法较为复杂，因此研究学者们开始关注视觉分辨率。为了提高3D光场显示的视觉分辨率，提出了一种基于深度学习获取预处理基元图像阵列（PEIA）的方法。在光场显示的成像过程中，透镜的像差会使成像平面上形成弥散斑。弥散斑之间的交叠区域可以被视为新的视觉像素，并被用作额外的信息载体。一个分辨率增强的卷积神经网络（CNN）被用来从高分辨率基元图像阵列（HEIA）中获取PEIA，将PEIA加载到LCD上，经过透镜阵列的光学变换和定向扩散膜的扩散作用，呈现出具有视觉分辨率增强的3D光场显示图像。在实验中，通过使用PEIA、透镜阵列以及定向扩散膜，展示了一个具有70°视角的光场显示，并提高了视觉分辨率。

A distortion correction method for the elemental images of integral imaging (II) by utilizing the directional diffuser is demonstrated. In the traditional II, the distortion originating from lens aberration wraps elemental images and degrades the image quality severely. According to the theoretical analysis and experiments, it can be proved that the farther the three-dimensional image is displayed from the lens array, the more serious the distortion is. To analyze the process of eliminating lens distortion, one lens and its corresponding elemental image are separated from the traditional II. By introducing the directional diffuser, the aperture stop of the separated optical system changes from the eye’s pupil to the lens. In terms of contrast experiments, the distortion of the improved display system is corrected effectively. In the experiment, when the distance between the reconstructed image and lens array is equal to 120 mm, the largest lens distortion is decreased from 46.6% to 3.3%.

A 360° light field 3D display system is presented, which consists of a liquid crystal display, a novel triplet lenses array, and a holographic functional screen (HFS). The mapping relationship among pixels, 3D objects, and viewing positions are investigated. The aberration analysis of the single lens is carried out both in the simulation and the experiment, which shows that it cannot provide an excellent 3D image to the viewers. In order to suppress the aberrations, “the primary aberration theory” and “the damped least-squares method” are used for optical analysis and lens design. A 3D image with aberration correction can be viewed around the proposed display system.