Efficient evaluation of a three-dimensional eye-box in a near-eye display using light-field acquisition of luminance distribution.

We propose, what we believe to be, a novel assessment methodology for evaluating three-dimensional (3D) characteristics of an eye-box volume in a near-eye display (NED) using a light-field (LF) data acquired at a single measuring distance. In contrast to conventional evaluation methods for the eye-box, where a light measuring device (LMD) changes its position in lateral and longitudinal directions, the proposed method requires an LF of the luminance distribution (LFLD) for the NEDs captured only at the single observation distance, and the 3D eye-box volume is evaluated via a simple post-analysis. We explore an LFLD-based representation for the efficient evaluation of the 3D eye-box, and the theoretical analysis is validated by simulation results using Zemax OpticStudio. As experimental verifications, we acquired an LFLD for an augmented reality NED at a single observation distance. The assessed LFLD constructed a 3D eye-box successfully over the distance range of 20 mm, which included assessment conditions where it was hard to measure the light rays' distributions directly in the conventional methodologies. The proposed method is further verified by comparing with actual observed images of the NED both inside and outside of the evaluated 3D eye-box.