Aerial full spherical HDR imaging and display

Abstract

This paper describes a framework for aerial imaging of high dynamic range (HDR) scenes for use in virtual reality applications, such as immersive panorama applications and photorealistic superimposition of virtual objects using image-based lighting. We propose a complete and practical system to acquire full spherical HDR images from the sky, using two omnidirectional cameras mounted above and below an unmanned aircraft. The HDR images are generated by combining multiple omnidirectional images captured with different exposures controlled automatically. Our system consists of methods for image completion, alignment, and color correction, as well as a novel approach for automatic exposure control, which selects optimal exposure so as to avoid banding artifacts. Experimental results indicated that our system generated better spherical images compared to an ordinary spherical image completion system in terms of naturalness and accuracy. In addition to proposing an imaging method, we have carried out an experiment about display methods for aerial HDR immersive panoramas utilizing spherical images acquired by the proposed system. The experiment demonstrated HDR imaging is beneficial to immersive panorama using an HMD, in addition to ordinary uses of HDR images.