摘要 |
A camera (10) includes a photocathode (30) operable in a night mode wherein electrons are generated in response to incident light, an active pixel sensor (36) including an array of pixels for sensing electrons in the night mode in response to a control signal, and a power supply control circuit for providing the control signal to the power supply (14) in response to a sensed incident light level. The control signal may be a gating signal having a duty cycle that increases as the sensed incident light level decreases. The camera (10) may be operable in a day mode wherein a fraction of the incident light is transmitted through the photocathode (30) and is sensed by the active pixel sensor (36). The camera (10) may further include an electron shielded light detector. A light detector signal generated by the electron shielded light detector may be used to control switching between the day mode and the night mode.
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