By Wendi Burke, Director of Marketing, IQinVision
The term Wide Dynamic Range (WDR) is used to describe the function of a camera designed to produce clearer, more actionable images and/or video in circumstances where back light and intense illumination can vary excessively, especially when both very bright and very dark areas are simultaneously present in the camera’s field-of-view. The wider the dynamic range, the better the camera’s sensor can accurately capture varying light intensities and then heighten the details visible within the area of view.
Examples where WDR functionality is most needed include:
The challenge in attaining consistently high-quality surveillance video is that the camera needs light to generate an image. But too much light and the image is blown out; too little light and the image is dark and unusable. Often, a scene has a wide range of light variation and the camera simply can’t adjust its iris settings or shutter speed to properly adjust for the optimal amount of light. Hence, WDR techniques have been developed to improve the speed of iris adjustment and thus enhance video quality and integrity.
There are two basic techniques commonly used to successfully provide WDR capability:
Of the two techniques, multi-frame imaging is the most commonly used by manufacturers supporting WDR capability for two main reasons. First, it is superior at capturing images in real-time, and secondly, it can process moving objects more quickly than non-linear sensors. Multi-frame imaging is also more cost effective and integration friendly because it is far more common in the marketplace. While non-linear sensors do perform well, they have not been widely adopted and current trends do not suggest this technique will overtake multi-frame imaging in popularity in the near future.
This article first appeared on IQinVision’s site. To read the article — which includes examples of photos taken with and without WDR, as well as tips for its use — click here.