Exploring the Limitations of Environment Lighting on Optical See-Through Head-Mounted Displays

Abstract

Due to the additive light model employed by most optical seethrough head-mounted displays (OST-HMDs), they provide the best augmented reality (AR) views in dark environments, where the added AR light does not have to compete against existing real-world lighting. AR imagery displayed on such devices loses a significant amount of contrast in well-lit environments such as outdoors in direct sunlight. To compensate for this, OST-HMDs often use a tinted visor to reduce the amount of environment light that reaches the user's eyes, which in turn results in a loss of contrast in the user's physical environment. While these effects are well known and grounded in existing literature, formal measurements of the illuminance and contrast of modern OST-HMDs are currently missing. In this paper, we provide illuminance measurements for both the Microsoft HoloLens 1 and its successor the HoloLens 2 under varying environment lighting conditions ranging from 0 to 20,000 lux. We evaluate how environment lighting impacts the user by calculating contrast ratios between rendered black (transparent) and white imagery displayed under these conditions, and evaluate how the intensity of environment lighting is impacted by donning and using the HMD. Our results indicate the further need for refinement in the design of future OST-HMDs to optimize contrast in environments with illuminance values greater than or equal to those found in indoor working environments. CCS CONCEPTS • Hardware → Displays and imagers; • Computing methodologies → Mixed / augmented reality; Perception.

Augmented Reality and Mixed Reality Measurement Under Different Environments: A Survey on Head-Mounted Devices

“…Studies that incorporate users' responses are the most common category among the types of measurement, likely because capturing direct feedback from users is a quick and easy way to obtain experimental data. Frequently used cases in this category are: health care (participants report their symptoms after using HMDs) [72], [73], comfort assessment (participants report whether they feel uncomfortable after using HMDs in different environments) [74], [75], environment interaction (participants provide feedback on changes in the environment) [76], [77], and questionnaire (the participants are asked to fill in questionnaires before or after the experiment) [49], [78].…”

“…One of the most frequently mentioned environmental factors is the difference between indoor and outdoor environments. For example, [77] mentions that most OST-HMDs add AR light so they do not have to compete against real-world lighting. However, when the OST-HMDs are exposed to direct sunlight in outdoor environments, they lose a significant amount of contrast.…”

“…Recent research has focused specifically on environment luminance affecting OST-HMDs, which use additive light models, meaning they lose a significant amount of contrast in high luminance environments (e.g., outdoor on a sunny day with no clouds). In [77], the authors designed a measurement to evaluate perceptual challenges with OST-HMDs and made some suggestions for future improvements.…”

Stay Positive: Non-Negative Image Synthesis for Augmented Reality

“…With such limitations, current hardware solutions compromise by relying on dimming the incoming light instead, using methods such as a sunglasseslike effect for OST and a darkened room for projector AR. In fact, current solutions use very dark tints, admitting only 15−20% [22,58] of the light from the original scene. While this delivers increased control over the pixel dynamic range, blocking too much light in the scene limits the kind of settings in which OST or projector AR can be applied.…”

18‐2: Assessment of Image Quality in Augmented Reality Displays Using a Computational Model of Target Detectability

“…Recent developments in augmented reality (AR) head-mounted displays (HMDs) have enabled new commercial [1] and medical imaging applications involving 3D lesion visualization [2,3], targeting [4], and image-guided surgery [5][6][7][8]. However, there are still unresolved technical challenges for AR HMDs such as inadequate resolution and field of view (FOV), limited display brightness [9], color [10] and image contrast degradation due to the see-through physical light field (e.g., outdoors or surgical operating room applications) [11].…”