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Background light compensation (BLC)
- Apr 13, 2018 -

BLC - Abbreviation for BackLight Compesation, also known as backlight compensation or backlight compensation, which can effectively compensate for the darkness of the main body of the camera when shooting in the backlight environment.

Usually, the AGC working point of the camera is determined by averaging the entire field of view, but if the field of view contains a very bright background area and a very dark foreground target, then the AGC work determined at this time Points may not be suitable for the foreground goals. Background light compensation may improve the foreground target display.

When the backlight compensation function is introduced, the camera only detects one sub-area of the entire field of view (for example, from the 80th to the 200th center of the line). The average signal level of this area is used to determine the working point of the AGC circuit. Since the average level of the sub-areas is very low, the AGC amplifier will have a higher gain, which will increase the amplitude of the output video signal, thereby making the subject picture on the monitor clear. The background picture at this time will be brighter, but the subjective brightness difference between the subject picture and the picture will be greatly reduced, and the visibility of the entire field of view will be improved.

When the background light compensation is on, the camera only averages one sub-area of the entire field of view to determine its AGC operating point. If the foreground target is located in the sub-area, the visibility of the foreground target is expected to improve. .