Bringing a colored head-down display symbology heads up: Display fidelity review of a low-cost see-through HMD

Within the U.S.-German project agreement on advanced technology for rotorcraft (PA-ATR) DLR conducts research on pilot aids for helicopter operations in DVE. For example, an HMD can provide visual cues to the pilot while flying eyes-out. With the HoloLens 2 as a low-cost HMD, the full-color waveguide display facilitates rapid prototyping of new color-coded symbology. To estimate the optical feasibility of the device, this paper presents findings on the see-through transmission of the combiner and a subjective rating of the color fidelity. The found issues can then be taken into account in the future design and development process of head-up display symbology.