Wide dynamic range
lastmod 2019-07-25created 2018-12-316 edits
Wide Dynamic Range (WDR) is a term used in the surveillance camera industry to refer to high-dynamic-range imaging.
About
Dynamic range arises from the difference in illuminance between the darkest and brightest parts of a given scene.
On an overcast day with few shadows, the dynamic range is low. There is no deep darkness and no extreme brightness. On a sunny day, however, there are distinct shadows, and there can be a large difference between the brightest and darkest parts, which results in a wide dynamic range (or high dynamic range).
Nature has a wider dynamic range than a camera or the human eye can perceive. A photo of a person standing in front of a bright window is one example. The camera can either expose the person properly and ignore the rendering of the scene outside shining through the window, or prioritize capturing the view outside the window and leave the person unexposed and dark. The dynamic range between the person and the outside scene is wider than the camera can handle.