Controlled Exposure
In the controlled exposure situation, the line-scan CCD sensor is brought into the reset condition before entering the exposure condition. It is often said that an "electronic shutter" is used.
The line-scan camera hosting the sensor experiences a periodical cycle paced by successive instants we will refer to as "line reset". The line reset pulses occur at the line frequency. Each line reset causes the following sequence:
- Exposure condition of some known duration.
- Transfer gate event.
- Readout process.
- Return to reset condition.
Operational sequence
It can be seen that the exposure duration is not equal to the line period. It can be made independent of the line rate.