Visibility of Interior Projections: Effects of Surface Characteristics

Today, projections are a part of everyday life - and they are becoming increasingly present in vehicle interiors. Exterior projections serve as a communication medium to interact with vulnerable road users and as a driver assistance system to improve road safety, such as projecting an extended turn signal for a cyclist. In addition, projections appear to be beneficial for use in vehicle interiors to enhance the character of the vehicle with graphic elements. When considering the focus on interior projections, the characteristics of the projection area vary depending on the material, colour, or geometry of the surface. Prior research defines that the material composition of interior surfaces plays a key role in the visibility of projections in the vehicle's interior. Differences in colour, texture, reflectivity and other characteristics can enhance or reduce the perceived experience for the car passenger. However, the specific relationships between surface properties and projection visibility have not been extensively studied in the context of vehicle interiors. This work defines the visibility requirements of a subject study with 33 participants with mesopic vision for different materials such as leather or knitted fabrics in various colours. For a detailed analysis, the resulting detection contrasts of the specific materials are compared using statistical measures to identify trends. The results indicate dependencies on either colour influence or material influence for the use case of projections in a vehicle interior.