High dynamic range video using split aperture camera.pdfVIP

High Dynamic Range Video Using Split Aperture Camera Hongcheng Wang ? , Ramesh Raskar ? , Narendra Ahuja ? ? Beckman Institute, University of Illinois at Urbana-Champaign (UIUC), IL, USA ? Mitsubishi Electric Research Laboratories (MERL), MA, USA Abstract We present a new approach to display High Dynamic Range (HDR) video using gradient based high dynamic range compression. To obtain HDR video, we utilize the split aperture camera. We apply a spatio-temporal gradient based video integration algorithm for fast and accurate in- tegration of the three input HDR videos into a low dynamic range video, which is suitable for display. The spatio- temporal video integration generates videos with temporal coherency and without artifacts. In order to improve the computational speed, we propose using a diagonal multi- grid algorithm to solve the Poisson equation. We show ex- perimental results on a variety of dynamic scenes. 1 Introduction A conventional digital camera typically provides a dy- namic range of two orders of magnitude through the CCD’s analog-to-digital converter (The ratio in intensity between the brightest pixel and the darkest pixel is usually referred to the dynamic range of a digital image). However, many real-world scenes have a larger brightness variation. Thus, some areas of the images captured by digital cameras are undersaturated or oversaturated. Tonemapping (also called tone reproduction) is used to establish an efficient way to reconstruct faithfully the high dynamic range radiance on a low dynamic range image for display. Display of HDR video is the main problem we address in this paper. To capture a high dynamic range image, several images with different exposures are usually taken to cover the whole range of a real scene using con- ventional cameras. Those images are combined into a sin- gle high dynamic range image (radiance map). High dy- namic range radiance maps are then recovered from these images [3]. Tonemapping methods are then applied to t