摘要
车载抬头显示系统(HUD)作为辅助驾驶技术,通过将驾驶信息叠加在路况实景上,减少驾驶员视线转移,提升驾驶安全并缓解眼疲劳。然而,传统的抬头显示系统对影像平面深度的缺乏感知,造成驾驶者在感知现实与影像时,焦距需要转换,无法全神贯注。提出了可实现连续深度调节的双光路增强显示车载抬头显示系统(AR-HUD)系统,基于全息成像理论,利用液晶空间光调制器(LCOSSLM)加载纯相位计算全息图,实现了虚像深度的连续可调。设计的可实现连续深度调整双光路ARHUD系统包括近光路和远光路两部分:近光路设计为定焦光路,虚像距离为3 m,远光路设计为连续深度调整光路,视场角分别为6°×1°和12°×4°,设计范围为7~15 m。所设计的双光路AR-HUD像差分析、动态畸变分析结果较好,显著提升成像质量。
Objective In-vehicle heads-up display systems allow drivers to see key data without turning their heads or looking down by virtually superimposing all types of driving information on the real-world view of the road.Head-up display systems require at least two or more virtual image depth planes to realize the augmented reality display effect truly.Currently,a variety of methods have been proposed for realizing AR-HUD systems with multiple depth planes.However,most of these designs suffer from the problem of insufficient depth of far-optical road imaging distance adjustment,which is unable to effectively respond to the visual convergence adjustment conflicts brought about by changes in vehicle speeds,affecting the driving experience and safety.Research has shown that holographic imaging technology can provide a realistic three-dimensional display effect and all the depth cues required by the human eye.At the same time,the holographic three-dimensional imaging content displayed by the use of spatial light modulator(SLM)depth of the virtual image continuously adjustable,a complete solution to the imaging of the convergence of the adjustment of conflicts,vertigo,to achieve an indeed augmented reality display effect.Methods Based on the holographic imaging principle,the impulse response function of the holographic display equipped with a spatial light modulator and the modulation transfer function are derived,and a dual-optical path AR-HUD system that can realize continuous depth adjustment is established(Fig.4).The optical system structure was constructed by acquiring windshield surface data and extracting the application area through Zemax(Tab.1).The dual-optical path AR-HUD system was designed with an off-axis reflective optical design to solve the superposition problem of the near-optical path and far-optical path information.The system optimizes the dot column plots,MTF curves,grid and dynamic aberrations of the near-and far-optical paths.It gives the projection distance and image width variation diagrams of the projection unit of the far-optical path(Fig.10).Results and Discussions At the end of the design optimization of the dual optical path AR-HUD system,the maximum value of the RMS radius is 10.933µm at 15 m.The RMS radius is 23.304µm at 3 m(Fig.6),the MTF curves,the MTFs are all greater than 0.5 at a cut-off frequency of 6 lp/mm(Fig.7).The maximum mesh aberration is less than 2%for the projected distance of 15 m.The maximum mesh aberration is less than 3%for the projected distance of 3 m(Fig.8).In the process of continuous adjustment of projection distance,the worst image quality is at the projection distance of 7 m(Fig.9),at this time,the RMS spot radius is within the radius of the Airy spot,the MTF can satisfy the requirement of more than 0.5 at 6 lp/mm,and the mesh aberration is less than 2%,which meets the acceptable range of the human eye.It can satisfy the driving demand in the actual use of the system.Conclusions Aiming at the problems of the traditional AR-HU,such as the inability of the final imaging to match the depth distance of the natural scene and the poor imaging quality caused by the windshield irregularities in the holographic HUD,the theoretical feasibility of the continuous depth adjustment system is verified through the research based on the holographic imaging theory.A dual-optical path AR-HUD system with continuous depth adjustment is designed.The aberration correction capability of free-form optics is utilised to accurately correct the irregular aberration introduced by the windshield,which significantly improves the imaging quality and ultimately obtains dual-optical path AR-HUDs with imaging distances of 3 m,7-15 m,and field of view angles of 6°×1°and 12°×4°with good imaging quality,respectively.At the same time,the dynamic aberration analysis of the designed dual-optical path AR-HUD system is carried out,which proves the stability of the designed AR-HUD system.
作者
柴嘉亮
董博
薛常喜
CHAI Jialiang;DONG Bo;XUE Changxi(School of Optoelectronic Engineering,Changchun University of Science and Technology,Changchun 130022,China;Key Laboratory of Advanced Optical Design and Manufacturing Technology of Jilin Province,Changchun University of Science and Technology,Changchun 130022,China)
出处
《红外与激光工程》
北大核心
2025年第7期286-295,共10页
Infrared and Laser Engineering
基金
吉林省自然科学基金项目(20220101124JC)。
