The technology of wide dynamic camera is a kind of technology used to make the camera see the feature of image under the very strong contrast. In some cases where the contrast of light and shade is too large, the general camera is limited by the sensitive characteristics of CCD, so the image usually has too bright background or too dark foreground. In view of this situation, the wide dynamic technology emerges as the times require, which solves this problem well.
When the object in the field of view of the conventional camera needs to look at the object at the door or outside the window when the background light is higher, the (BLC) mode is usually compensated by the central backlight, which mainly depends on raising the brightness of the central part of the field of view. Reduce the brightness of the surrounding part of the field of view to see the object in the center position. Backlight compensation, also known as backlight compensation, divides the picture into different regions, each exposed separately. In some applications, the field of view may contain a bright area, while the subject is surrounded by the bright field. At this time, because the signal level detected by AGC is not low, the gain of amplifier is very low, so it can not improve the brightness of the main body of the picture. When the backlight compensation is introduced, the camera detects only one sub-region of the whole field of view. The working point of the AGC circuit is determined by calculating the average signal level in this area. Because the average level of the sub-region is very low, the AGC amplifier will have a higher gain, which will increase the amplitude of the output signal, thus make the main drawing on the monitor clear, and greatly reduce the subjective brightness difference between the background picture and the main picture. The visibility of the entire field of view is improved. The backlight compensation can improve the brightness of the subject, but the image quality will more or less deteriorate. The technology of wide motion is two exposures at the same time, one time slowly, and then combine to make it possible to see the bright and dark objects on the screen at the same time. Although both of them are to overcome the measures taken to see the target clearly under the condition of strong backlight environment, the backlight compensation is at the cost of sacrificing the contrast of the picture, so in some sense, the wide dynamic technology is the upgrade of backlight compensation.
