CCD Dynamic Range: Buyers Need Comparable Specifications

Albert J.P. Theuwissen, Philips Research

The dynamic range of a solid-state image sensor is one of the main characteristics if the device is used in high-end digital still photography. In video applications, the monitor or the human eye averages the noise from picture to picture. In a single-shot application, however, the overall noise in the picture is frozen on the monitor or on the hard copy. To make digital still applications shot-noise limited with an acceptable signal-to-noise ratio, the sensor must provide a large dynamic range.
Most detector buyers know already that sensor manufacturers' dynamic range specifications are not comparable in a practical sense. Several CCD suppliers specify their devices without taking into account the dark current effects and the temperature influence. In fact, the dynamic range depends very much on various parameters related to the CCD's temperature and driving electronics.