| 摘要 |
Apparatus (10) that performs automatic gain control (AGC) for an electronic imaging camera (30), especially in outdoor surveillance applications. A fiber optic link (13) is used to collect ambient light and couple this light onto a small portion of a light sensing array (35) of the camera (30). A reference voltage produced by the light sensing array (35) in response to the light from the fiber is used by AGC circuits (20) in the camera (30) to control the integration time of light sensing elements of the array (35), the gain of the camera's video amplifier (41), and lens aperture, if necessary. These camera gain controls are adjusted to maintain the reference voltage derived from the light provided by the fiber optic link (13) to be within a predefined range as the ambient light level varies due to weather conditions and time of day. Methods of providing automatic gain control correction are also disclosed. <IMAGE> |
