The Wide Dynamic Range (WDR) feature on Video Security Cameras is one of the most important image improvements on security cameras, alongside the higher resolution cameras evolution we see in the video surveillance industry today. WDR is the camera’s ability to see in contrasting levels of light such as when a camera is pointed towards a glass door or window, the background becomes “washed out” with the sun at different levels.
WDR is intended to provide clear images when the intensity of illumination varies in the FOV when there are very bright and very dark areas concurrently in the FOV. WDR correct the image for the intense lighting surrounding an object and enhances the ability to distinguish features and shapes within the image.
WDR is many times not the default setting on the cameras, and it should be. When WDR is activated, the typical response is… , wow! The system response is details in all areas of the Field of View(FOV) and a brilliant picture. The customer first sees the benefit of the high resolution 1080p cameras, and believes that is a great picture, but once WDR is activated and they see the resulting image, the clarity and brilliance of the high resolution camera producing clear, low noise images with good contrast.
Security video applications have various lighting situations that cannot be controlled, therefore the proper camera selection is critical to covering selected FOVs. In many video security situations there will be many locations with very contrasting brightness areas, which are not managed effectively by a standard non-WDR camera. Place a 1080p nice camera without WDR at the west-setting sun covering a parking lot, and you will get high-resolution flash-out with the results being useless video and poor results.
True WDR vs Software WDR – Digital WDR (D-WDR) is a software-based technique that optimizes image quality by adjusting the gamma (γ) value to enhance dark areas. Digital WDR does not offer the same quality as True WDR. True WDR is achieved by a double exposure technique that takes one exposure with longer exposure time to get the detail in dark area. Then another exposure is taken with a shorter exposure time to get the detail in very bright areas. The two or more exposures are then combined into a single frame. WDR is a feature that would benefit most all camera locations and should be a requirement for any outdoor camera covering any critical areas.