High dynamic range (HDR) is a dynamic range higher than usual, synonyms are wide dynamic range, extended dynamic range, expanded dynamic range.
The term is often used in discussing the dynamic range of various signals such as s, videos, audio or radio. It may apply to the means of recording, processing, and reproducing such signals including analog and digitized signals.
The term is also the name of some of the technologies or techniques allowing to achieve high dynamic range images, videos, or audio.
In this context, the term high dynamic range means there is a lot of variation in light levels within a scene or an image. The dynamic range refers to the range of luminosity between the brightest area and the darkest area of that scene or image.
(HDRI) refers to the set of imaging technologies and techniques that allow to increase the dynamic range of images or videos. It covers the acquisition, creation, storage, distribution and display of images and videos.
Modern movies have often been filmed with cameras featuring a higher dynamic range, and legacy movies can be converted even if manual intervention would be needed for some frames (as when black-and-white films are converted to color). Also, special effects, especially those that mix real and synthetic footage, require both HDR shooting and rendering. HDR video is also needed in applications that demand high accuracy for capturing temporal aspects of changes in the scene. This is important in monitoring of some industrial processes such as welding, in predictive driver assistance systems in automotive industry, in surveillance video systems, and other applications.
Multi-exposure HDR capture
In photography and videography, a technique, commonly named high dynamic range (HDR), allows to increase the dynamic range of captured photos and videos beyond the native capability of the camera. It consists of capturing multiple frames of the same scene but with different exposures and then combining them into one, resulting into an image with a dynamic range higher than those of individually captured frames.