Overview light attenuation display: (Left) Our prototype of a light attenuation display positioned close to the user-perspective camera’s viewing point. (Middle) An example image created with our light attenuation display; the successive gray-scale images are input phase images and the bottom image is a real color image captured by a user-perspective camera. (Right) Example application of enhancing the real-world view by using the system. The view of a colored checkerboard is augmented by alignment of our spatial color filter with the scene, which results in an augmented view of the same colored checkerboard but with a more vivid appearance. Note that the two images are captured under the same illumination with the same capture settings, including exposure time, gamma, and white balance.
Abstract: We present a display for optical see-through near-eye displays based on light attenuation, a new paradigm that forms images by spatially subtracting colors of light. Existing optical see-through head-mounted displays (OST-HMDs) form virtual images in an additive manner-they optically combine the light from an embedded light source such as a microdisplay into the users' field of view (FoV). Instead, our light attenuation display filters the color of the real background light pixel-wise in the users' see-through view, resulting in an image as a spatial color filter. Our image formation is complementary to existing light-additive OST-HMDs. The core optical component in our system is a phase-only spatial light modulator (PSLM), a liquid crystal module that can control the phase of the light in each pixel. By combining PSLMs with polarization optics, our system realizes a spatially programmable color filter. In this paper, we introduce our optics design, evaluate the spatial color filter, consider applications including image rendering and FoV color control, and discuss the limitations of the current prototype.
Acknowledgements: This work was partially supported by JSPS KAKENHI Grant Number- sJP17H04692 and JP17K19985, Japan; and by JST PRESTO Grant Number JPMJPR17J2, Japan. Tobias Langlotz is partially supported by Callaghan Innovation, host of the Science for Technological Innovation National Science Challenge, Seed Project 52421, New Zealand. We also thank Prof. Masahiro Yamaguchi for sharing his expertise on optical imaging and polarization interference.