Measure what the human eye sees: optical testing of AR/VR headsets

AR/VR devices are an exciting new way of visual interaction with the environment in real time. Besides the virtual display, the headsets contain several types of light sources and sensors that enable users to immerse themselves in the virtual world. To ensure a perfect user experience, extensive and highly accurate optical tests are necessary. Besides standard optical tests, new parameters that are specific to near-eye displays, e.g. eyebox dimensions, are critical for quality assurance. A uniform display is fundamental for an undisturbed viewing experience. Accurate luminance and colors are a basic requirement for natural perception. Contrast is important for good legibility of virtual text. Distortion of the image due to tolerances in the mechanical and optical setup have an immediate impact on the display quality and must be kept below the human perception threshold.

In order to meet these test requirements, the LumiTop AR/VR 2D imaging colorimeter designed by Instrument Systems has been optimized for the production testing of near-eye displays (NEDs). The AR/VR lens in the LumiTop simulates the human eye and measures color and luminance exactly as seen by the user. A wide camera field of view (120°), various pupil sizes and an adjustable focus distance facilitate a wide range of testing applications.

The unique periscope lens design guarantees easy access to the NED and enables an optimal measurement position, even under the tight spatial constraints of fully assembled headsets. A hardware trigger enables perfectly synchronized one-shot two-eye measurements with two LumiTops.

LumiTop AR/VR is also based on the proven LumiTop principle. While an RGB camera takes the image of the NED in one shot, a reference spectroradiometer corrects the results to yield highly accurate absolute luminance and color values. The measurement results are fully traceable to national standards and therefore allow low manufacturing tolerances, especially important for distributed manufacturing. Simultaneous measurement of a 2D image, spectrum and flicker makes LumiTop a very fast, comprehensive and highly accurate imaging light measurement device for AR/VR tasks in production. Instrument Systems also offers testing solutions for the IR sources (NIR LED, VCSEL) often used for gesture and object recognition within an AR/VR headset.