基于景深的增强现实光学系统虚像视距测量方法

Field Depth Based Virtual Image Viewing Distance Measurement in Augmented Reality Optical System

针对AR光学系统中虚像视距(VID)测量方法基于主观判断、易受摄影系统的景深干扰等问题,从VID的测量原理出发,提出了利用景深特性使AR虚像视距与参考实物物距保持一致的方法,通过构建实验系统和分析算法,采用基于边缘的空间频率响应检测同一摄影系统在拍摄虚像和参考实物过程中图像清晰度的相对变化,将VID转换为摄影系统在相应对焦位置时的远景距离,实现对AR光学系统VID的定量测量。实验结果表明:设计的VID测量系统的测量结果(1397 mm)与所测的AR波导镜片样品的理论设计值(1400 mm)相符,说明了该测量系统的有效性;测量误差为10~40 mm,即将理论误差降低到传统测量方法的1.6%~6.45%,显著提高了VID的测量精度。该方法仅基于常用实验器件即可实现AR光学系统VID的测量,有利于将VID检测系统更便捷地投入到AR设备的生产和研发环境中,助力AR设备设计和生产工艺的进步。

Due to their subjective nature,conventional virtual image viewing distance(VID)measurement methods in AR optical systems are easily disturbed by field depth of the photography system.To mitigate this issue,this study proposes a method to stabilize object distances between virtual images and actual reference objects using the field depth property based on the measurement principle of VID.In our experimental analysis,the edge-based spatial frequency response is used to measure the relative change of image sharpness in shooting virtual images and reference objects by the same photography system.During this process,the VID is converted into view distance at the corresponding focus position,and a corresponding quantitative measurement is returned.Experimental results show that the VID measurement result generated in this study(1397 mm)matches the theoretical design value of the AR waveguide lens sample(1400 mm),which demonstrates the measurement system’s validity.Furthermore,a measurement error of 10-40 mm is observed,which is 1.6%-6.45%of that generated by conventional measurement methods.Because this method enables VID measurement in common experimental optical systems,it is highly applicable across AR-equipped devices,which in turn should help advance these devices’design and production.