A practical method to Extending Dynamic Range of CCD Camera

摘要

CCD (Charge Coupled Device) is the most popular detector for camera to detect low levels of light for wavelengths from 300nm to 1100nm. Contemporary CCD has read noise level equivalent to a few electrons, and Well capacity over 100,000 electrons .In order to take full advantage of these characteristics, it needs the dynamic of ADC must exceed the dynamic of the CCD. That is the number of bits provided by the ADC must exceed 16 bits. While the high reliability and inexpensive 16-20 bit A/D converter is few. In this paper, we firstly analyze CCD noise and then present the principle to extend the dynamic of the CCD in signal processing chain using two low resolution ADC with different sensitivity. At last we present a concrete example of improving the resolution of the ADC is by tow parallel low resolution ADCS with developing software to suitably process the converted analog-to-digital signal to achieve the same effect as a higher resolution ADC.