Objective Measurements of Background Color Shifts Caused by Optical See-Through Head-Mounted Displays

Optical see-through head-mounted displays (OST-HMDs) have been increasingly used in research and industrial applications as Augmented Reality (AR) support devices. However, problems still exist that prevent their use as general-purpose devices. One of these issues is the color blending problem between content and background colors. More specifically, the light from the background overlaps with the light from the OST-HMD and shifts the color of OST-HMD's light from its intended display intensity and color. Though color compensation methods exist, in order to properly compensate for light shifts, we need to know how the background color will affect the light that eventually hits the user's eye when combined with the OST-HMD image. In this paper, we study how background colors shift as a result of passing through the OST-HMD's optics in order to better inform the development of color compensation methods. We measured the background color objectively for the Magic Leap 1, the HoloLens (first gen), and the HoloLens 2 and evaluated results. We found that all three OST-HMDs shift background color to a perceptible degree, and that the degree of shift depends on the original background color.