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。

在裸眼3D立体视频观看中，由于存在辐辏调节的矛盾，观看者会产生诸如眩晕、呕吐等视疲劳症状，尤其在医疗、A/VR等场景下，3D视频观看通常为任务驱动，眼动行为由于受到主观控制，单一的眼动特征很难准确评估视觉疲劳，更无法得到视疲劳等级，导致视疲劳无法及时被发现，从而造成不可预估的损失。针对以上问题，本文提出了一种基于多种眼动行为的3D视疲劳等级评估模型，旨在观看3D内容时，通过对注视、扫视、眨眼等眼动行为进行建模分析，得到实时视疲劳等级。本文采用主客观相结合的方法进行实验：受试者观看3D内容，实验人员记录受试者主观打分并利用眼动仪提取受试者客观眼动行为；通过进行相关性分析，探究任务驱动下能够表征3D视疲劳的各种客观眼动行为；利用神经网络建立基于16种眼动行为的视疲劳四等级评估模型。模型对3D视疲劳等级的预测准确率达到82%，证明了模型的有效性。

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.

针对基于数字微镜器件的全息显示分辨率受限的问题，提出了一种大尺寸、高分辨率计算全息显示方法。本文利用计算机渲染或相关变换方法生成高分辨率输入图像，利用菲涅尔衍射算法和傅立叶变换并行计算提升全息图的分辨率，根据数字微镜器件特性进行衍射图像的时空复用与动态融合，有效提升计算全息显示的分辨率与动态效率。实验结果表明，该方法可实现大尺寸、高分辨率的动态全息显示效果，突破了数字微镜器件固有的像素数目及分辨率限制，使用像素分辨率为2K的数字微镜器件可显示8K甚至更高分辨率的重建图像，尺寸可以达到82 mm甚至更大。

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。

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 holographic visualization of volume data based on adjustable ray to optical-wave conversion is presented. Computer-generated holograms are generated by emitting multiple rays to sample the volumetric field. Equal interval sampling, object light wave adjustment, and information composition are sequentially performed during the march of rays. The program is accelerated in parallel to reduce the total time, and the reconstructions are dynamically adjusted to express different parts of an object. Optical experiments verify that the proposed method can holographically reconstruct the surface and interior information of objects.

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%.