Door phones with WDR backlight compensation

WDR (backlight compensation)

— cameras with backlight compensation based on WDR technology.

Flare occurs, in particular, when one or more bright light sources appear in the frame against a dark background. Around such sources, a halo often appears, “muffling out” part of the image. And if you simply reduce the sensitivity of the matrix to eliminate this effect, then the surrounding, relatively dark background will be poorly visible.

Backlight compensation technologies are designed to eliminate such phenomena. And WDR (Wide Dynamic Range — “extended dynamic range”) is the most effective of these technologies used in outdoor panels. The principle of its operation is that the camera takes several frames in a row with different exposures, and then combines them into one picture. As a result, dark areas are brightened, and overexposures are darkened, and the output is an image with extremely uniform illumination. In addition to WDR, modern outdoor panels can also use BLC technology, which works as follows: each frame is divided into many sections, and each of these sections, if necessary, is adjusted separately.

It is also worth noting that the original WDR technology is implemented at the hardware level, using additional equipment in the camera. An alternative option is DWDR — "digital" WDR, implemented by post-processing the resulting image with software tools. DWDR is noticeably cheaper, but inferior to the original WDR in terms of efficiency. Therefore, calling panels with DWDR are not included in this category.