Backlight compensation, strong light suppression, and wide dynamics are widely used functions of surveillance cameras. A reasonable monitoring screen can be obtained by setting various parameters reasonably:
Backlight compensation: Also known as backlight compensation, the picture is divided into several different areas, each of which is exposed separately. In some applications, the field of view may contain a very bright area, while the contained subject is surrounded by a bright field, the picture is dim and layerless. At this time, since the signal level detected by the AGC is not low, the gain of the amplifier is very low, and the brightness of the main body of the picture cannot be improved. When the backlight compensation is introduced, the camera detects only one sub-area of the entire field of view. The average signal level of this region determines the operating point of the AGC circuit.
Strong light suppression: refers to the video information of the strong light part in the image is processed by the DSP, and the brightness of the video signal is adjusted to the normal range, so as to avoid the front and back contrast in the same image is too large.
Main function: The traditional CCD has a dynamic range limitation. In the process of acquiring an image, only the entire image is sampled once, and there is bound to be an overexposure of a bright area in the entire image or an underexposure of a darker area. The function of strong light suppression is to use DSP technology. The simple meaning is to weaken the strong light part and brighten the dark light part to achieve light balance.
Wide Dynamics: Width Dynamics is a technique used by cameras to see the characteristics of an image in very strong contrast. When a high-luminance area illuminated by a strong light source (daylight, luminaire, or reflective) and a relatively low-intensity area such as a shadow or a backlight are simultaneously present in the image, the image outputted by the camera may appear bright, and the white area becomes white due to overexposure. The dark area becomes black due to insufficient exposure, which seriously affects the image quality. The camera's performance in the brightest and darker regions in the same scene is limited. This limitation is commonly referred to as the "dynamic range."
