1 April 1998 Model for equivalent ISO CCD camera speeds
Author Affiliations +
The expanding use of CCD sensor based, digital cameras necessitates the development of a reliable method of determining an equivalent ISO speed for such cameras. This paper will briefly describe the physical differences between image capture, and the signal and noise properties of film and CCD based imaging systems. The model first addresses the ISO speed of a monochrome CCD sensor. The results of this model indicate that an equivalent ISO speed can be found when the exposure, Em, in Lux-seconds at a signal-to- noise ration of 30 is used to calculate the speed from the expression developed for film based systems, ISO speed equals 0.8/Em. The model shows that calibration exposures of 0.01 seconds or less must be used to eliminate the effect of dark current on determining the 'correct' ISO speed. The model is then sued to calculate the effective ISO speed for a series of CCD sensors for different pixel areas, nose characteristics and quantum efficiencies. The same model is used for color cameras by introducing a color filter. The model is also used to determine what set of color filters will provide a balanced exposure for a given light source and what electronic processing must be done to compensate for different equivalent ISO speeds between the color filter elements. The effect on ISO speed and color balance as a function of illuminant is considered. The model is also used to map the signal-to-noise characteristic of the CCD camera under usage equivalent to a film based camera.
© (1998) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Michael A. Kriss, Michael A. Kriss, "Model for equivalent ISO CCD camera speeds", Proc. SPIE 3302, Digital Solid State Cameras: Designs and Applications, (1 April 1998); doi: 10.1117/12.304586; https://doi.org/10.1117/12.304586


PAU camera: detectors characterization
Proceedings of SPIE (September 24 2012)
Recent advances in ultrasensitive CCD camera technology
Proceedings of SPIE (June 03 2002)
Quantum efficiency of the XMM pn-CCD camera
Proceedings of SPIE (October 21 1999)

Back to Top