| 摘要 |
An active pixel sensor for use in ambient light conditions together with a controlled light source, the sensor producing a difference signal which is indicative of the intensity of light incident on the sensor from the controlled light source. The sensor operates in two phases and includes a photodetector coupled to processing circuitry coupled to storage circuitry. In the first phase, the photodetector generates an ambient light signal and the processing circuitry memorises the ambient light signal. In the second phase the photodetector generates a total light signal, the processing circuitry subtracts the stored memorised ambient light signal from the total light signal to produce the difference signal, and the storage circuitry stores the difference signal. The sensor alternates between the first and second phases in response to receiving a strobing signal, the strobing signal and the controlled light source being synchronised. |
