High dynamic range

About: High dynamic range is a research topic. Over the lifetime, 4280 publications have been published within this topic receiving 76293 citations. The topic is also known as: HDR.

A wide field, high dynamic range, stereographic viewer

Abstract: In this paper we present a High Dynamic Range viewer based on the 120-degree field-of-view LEEP (Large Expanse Extra Perspective) stereo optics used in the original NASA virtual reality systems. By combining these optics with an intense backlighting system (20 Kcd/m2) and layered transparencies, we are able to reproduce the absolute luminance levels and full dynamic range of almost any visual environment. This is important because it allows us to display environments with luminance levels that would not be displayable on a standard monitor. This technology may enable researchers to conduct controlled experiments in visual contrast, chromatic adaptation, and disability and discomfort glare without the usual limitations of dynamic range and field of view imposed by conventional CRT display systems. In this paper, we describe the basic system and techniques used to produce the transparency layers from a high dynamic range rendering or scene capture. We further present a series of psychophysical experiments demonstrating the device's ability to reproduce visual percepts, and compare this result to the real scene and a visibility matching tone reproduction operator presented on a conventional CRT display.

Representing and reconstructing high dynamic range images

Abstract: A high dynamic range image can be recovered from a full-resolution lower-dynamic-range image and a reduced-resolution higher-dynamic-range image. Information regarding higher spatial frequencies may be obtained by extracting high spatial frequencies from the lower-dynamic-range image. In some embodiments an approximate impulse-response function is determined by comparing the higher- and lower-dynamic range images. A scaling image obtained by applying the impulse-response function to a high-frequency band of the lower-dynamic range image is combined with an upsampled higher-dynamic range image to yield a reconstructed image.

High dynamic range video with ghost removal

Abstract: We propose a new method for ghost-free high dynamic range (HDR) video taken with a camera that captures alternating short and long exposures. These exposures may be combined using traditional HDR techniques, however motion in a dynamic scene will lead to ghosting artifacts. Due to occlusions and fast moving objects, a gradient-based optical flow motion compensation method will fail to eliminate all ghosting. As such, we perform simpler block-based motion estimation and refine the motion vectors in saturated regions using color similarity in the adjacent frames. The block-based search allows motion to be calculated directly between adjacent frames over a larger search range, yet at the cost of decreased motion fidelity. To address this, we investigate a new method to fix registration errors and block artifacts using a cross-bilateral filter to preserve the edges and structure of the original frame while retaining the HDR color information. Results show promising dynamic range expansion for videos with fast local motion.

Demystifying High-Dynamic-Range Technology: A new evolution in digital media.

Abstract: High-dynamic-range (HDR) technology has attracted a lot of attention recently, especially in commercial trade shows such as the Consumer Electronics Show, the National Association of Broadcasters Show, the International Broadcasting Convention, and Internationale Funkausstellung Berlin. However, a great deal of mystery still surrounds this new evolution in digital media. In a nutshell, HDR technology aims at capturing, distributing, and displaying a range of luminance and color values that better correspond to what the human eye can perceive. Here, the term luminance stands for the photometric quantity of light arriving at the human eye measured in candela per square meter or nits. The color refers to all the weighted combinations of spectral wavelengths, expressed in nanometers (nm), emitted by the sun that are visible by the human eye (see Figure 1). The human eye can perceive a dynamic range of over 14 orders of magnitude (i.e., the difference in powers of ten between highest and lowest luminance value) in the real world through adaptation. However, at a single adaptation time, the human eye can only resolve up to five orders of magnitude, as illustrated in Figure 2. Dynamic range denotes the ratio between the highest and lowest luminance value. As reported in Table 1, there are different interpretations for dynamic range, depending on the application. For instance, in photography, dynamic range is measured in terms of f-stops, which correspond to the number of times that the light intensity can be doubled.