In most augmented reality (AR) or virtual reality (VR) devices, a virtual image is formed in front of the eye at a specific focal distance. Focal distance is the distance to the virtual image produced by the virtual image optics and is a display parameter of interest. In this study, a method to measure the focal distance is proposed. A positive lens was added adjacent to the AR device, and the image of the virtual image formed by this lens was photographed at the different distances with the translation of complementary metal–oxide–semiconductor (CMOS), which was used as two‐dimensional spatial sensor arrays. Grating pattern with the various line thickness was used as input signal. Once the distance of the image of the virtual image formed by the addition of the positive lens was determined, the focal distance of the virtual image was found from the lens equation. The measurement accuracy of the proposed method with regard to the CMOS translation step was compared with the other conventional methods.

中文翻译：

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增强现实或虚拟现实设备中虚拟图像的焦距的测量方法

在大多数增强现实（AR）或虚拟现实（VR）设备中，虚拟图像是在特定的焦距下在眼前形成的。焦距是由虚像光学器件产生的到虚像的距离，并且是关注的显示参数。在这项研究中，提出了一种测量焦距的方法。在AR设备附近添加了一个正透镜，并通过互补金属氧化物半导体（CMOS）的平移在不同距离拍摄了由该透镜形成的虚像的图像，该图像被用作二维空间传感器阵列。具有各种线宽的光栅图案被用作输入信号。一旦确定了通过增加正透镜形成的虚像的图像的距离，从镜头方程中可以找到虚像的焦距。将所提出的方法在CMOS平移步骤方面的测量精度与其他常规方法进行了比较。