Wearable augmented reality optical see through displays based on integral imaging

In the context of Augmented Reality (AR), industrial pioneers and early adopters have considered the wearable optical see-through (OST) displays as proper and effective tools in applications spanning from manufacturing and maintenance up to the entertainment field and the medical area, because they provide the user with an egocentric viewpoint maintaining the quality of the visual perception of the real world. The common OST displays paradigm entails intrinsic perceptual conflicts owing to mismatched accommodation between real 3D world and virtual 2D images projected over semitransparent surfaces. Such paradigm is suitable for augmenting the reality with simple virtual elements (models, icons or text), but various shortcomings remain in case of complex virtual contents. The major shortcoming is due to the tedious and error prone calibration methods required to obtain geometrical consistency, pivotal in many of the aforementioned fields of application. These shortcomings are due to the intrinsic incompatibility between the nature of the 4D light field, related to the real world, and the nature of the virtual content, rendered as a 2D image. In this paper we describe a radical rethinking of the wearable OST displays paradigm by generating, through integral imaging technique, the virtual content as a light field, in order to overcome the typical limitations of the traditional approach. This paper describes the hardware components and an innovative rendering strategy in more details in respect to a previous work. Furthermore we report early results with the implementation of the integral imaging display using a lens array instead of a pinhole array.