One of the most significant advances in light detection methods in recent years is the development of CCD technology. There is a great difference, however, in merely detecting light versus providing accurate photometric measurements of a field of view. Many factors must be taken into account in controlling CCD and camera characteristics, data acquisition, and subsequent data processing. Calibration techniques are particularly significant if we are to ensure proper photometric analysis.
K. Frank Lin,
"High-accuracy photometry using CCD technology", Proc. SPIE 2550, Photodetectors and Power Meters II, (26 September 1995); doi: 10.1117/12.221415; https://doi.org/10.1117/12.221415