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Augmented Reality (AR) creates a photorealistic view by either superimposing or subtracting computer‐generated scenes onto a user's view of the real physical world. The challenge for the AR display is to convince the user whether it is effective by conveying the sense of reality. It can be quantified into several topics: 1) Virtual image quality in the dark room; 2) Virtual image quality with the bright background as an example of color image quality degeneration shown in Figure 1; and 3) Real world scenes effected by the optics and virtual image of the AR display. 4) Performance of the virtual image merged with the real scene.

VR/AR eyewear displays are truly here in 2018, but the challenge remains. One of the potential benefits of VR/AR applications is the immersive experience with the virtual world that can suspend disbelief. However, the drawback is that the technology still needs improvement. Currently, most commercially available VR displays may only output 10‐20 ppd (pixel per degree) in angular resolution due to the limitation of the microdisplays. However, our human eye can dissolve the image details up over 60 ppd. Thus, the lack in image resolution can easily lose its capability of fooling the user. In order to improve the design such as the microdisplay panel or imaging optics, we need to evaluate the characteristics of the virtual images in the visual aspect. In conventional display measurement, pixel angular resolution is applied, but the pixel number is only a physical definition. Additionally, for a small pixel structure, it may have high spot luminance and low average image luminance which would cause an uncomfortable stimulus to the user. Therefore, what is a better way to define image resolution in VR/AR displays? In this work, we reviewed the current methods proposed in IEC TC110 on image quality. Then, some of the key factors that involve the image resolution measurement would be presented. We first reviewed the fundamental aspects of visual‐spatial perception and the mechanism of the human eye, and then we explained why such display limits the image quality of VR/AR display systems. In addition, we presented other measurement parameters including the newly proposed term ‐ pixel angular density, MTF (modulation transfer function) as well as the virtual image quality in static and moving picture conditions. These parameters were addressed in this work from introducing the definition to how and why they are necessary to test. An example of measurement in static picture resolution is shown in Figure1. The contrast modulation measurement is performed to determine static picture resolution. The test patterns and the calculation formula are critical in the measurement. The goal of this work is to provide some essential and fundamental guidelines to manufactures and engineers in the image resolution measurement of VR/AR systems.