High Dynamic Range Imaging

Abstract

High dynamic range (HDR) images and video contain pixels, which can represent much greater range of colors and brightness levels than that offered by existing, standard dynamic range images. Such “better pixels” greatly improve the overall quality of visual content, making it appear much more realistic and appealing to the audience. HDR is one of the key technologies of the future imaging pipeline, which will change the way the digital visual content is represented and manipulated. This article offers a broad review of the HDR methods and technologies with an introduction to fundamental concepts behind the perception of HDR imagery. It serves as both an introduction to the subject and a review of the current state of the art in HDR imaging. It covers the topics related to capture of HDR content with cameras and its generation with computer graphics methods; encoding and compression of HDR images and video; tone mapping for displaying HDR content on standard dynamic range displays; inverse tone mapping for upscaling legacy content for presentation on HDR displays; the display technologies offering HDR range; and finally image and video quality metrics suitable for HDR content.

The high dynamic range imaging pipeline : Tone-mapping, distribution, and single-exposure reconstruction

“…The gamma correction operation can also be extended to account for the display and viewing environment, with the gamma-offset-gain model [34,175],…”

“…It also places the individual thesis papers in relation to previous work, demonstrating how they contribute to the area. For a wider description of HDR imaging and its applications, the reader is referred to recent books on the topic, treating HDR imaging in general [28,175,211] and specializing on HDR video [49,71].…”

High dynamic range image processing using manifold-based ordering

“…This results in a more contrasted and sharper tone-mapped image. This is assessed by the values of the log-PSNR values (a quality metric for HDR images [25] 1 ).…”

Physically Based Rendering of Synthetic Objects in Real Environments

“…From a purely physical standpoint, the scattering of light inside the eye limits the maximum contrast that can be perceived by the eye to about 1 ∶ 3000 [144]. However, as the eye rapidly changes gaze and adapts locally, it is commonly believed that we can perceive scenes with a dynamic range of 1 ∶ 40000 or more [144], far more than the capabilities of a traditional camera sensor.…”

“…From a purely physical standpoint, the scattering of light inside the eye limits the maximum contrast that can be perceived by the eye to about 1 ∶ 3000 [144]. However, as the eye rapidly changes gaze and adapts locally, it is commonly believed that we can perceive scenes with a dynamic range of 1 ∶ 40000 or more [144], far more than the capabilities of a traditional camera sensor. In fact, with adaptations over time, relevant for video applications, the human visual system is believed to be capable of perceiving a dynamic range of about 1 ∶ 10 14 , from a moonless night to bright daylight [63].…”