| 摘要 |
A system comprises an imaging pixel array 203, such as a complementary metal oxide silicon (CMOS) array, and an exposure level determining means 207 that generates a signal indicating the level of exposure of the sensor array. A voltage supply adjuster 206 then operates to vary the voltage supplied to the imager in response to the exposure level indicator. The voltage supply is increased for higher exposure levels, expanding the dynamic range of the array, and decreased for lower exposures, accordingly reducing pixel noise levels. The device for determining exposure may comprise a programmable gain amplifier (PGA 301, Figure 3A), analogue to digital converter (ADC, 303) and gain controller (305). A comparator (207, Figure 3B) may be used to compare digitised signals output from the array with a target, threshold value (309).
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