| 摘要 |
During the integration time, the voltage applied to the electrodes of a charge coupled device (CCD) imager under which radiation induced charges are to be collected is changed as a function of time. To obtain dark current reduction, a linear ramp may be employed which starts at a relatively low voltage level. The lower average voltage employed to collect charge signals results in lower dark currents (especially at locations where defects are present) but does not appreciably change the number of radiation induced charge carriers which are collected. To obtain increased dynamic range, the voltage may be changed in non-linear fashion, for example, increased in discrete steps or increased by changing the slope of the voltage waveform. Similar techniques may be employed for gamma ( gamma ) correction. |
