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Proceedings Paper

Computation of dark frames in digital imagers
Author(s): Ralf Widenhorn; Armin Rest; Morley M. Blouke; Richard L. Berry; Erik Bodegom
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Paper Abstract

Dark current is caused by electrons that are thermally exited into the conduction band. These electrons are collected by the well of the CCD and add a false signal to the chip. We will present an algorithm that automatically corrects for dark current. It uses a calibration protocol to characterize the image sensor for different temperatures. For a given exposure time, the dark current of every pixel is characteristic of a specific temperature. The dark current of every pixel can therefore be used as an indicator of the temperature. Hot pixels have the highest signal-to-noise ratio and are the best temperature sensors. We use the dark current of a several hundred hot pixels to sense the chip temperature and predict the dark current of all pixels on the chip. Dark current computation is not a new concept, but our approach is unique. Some advantages of our method include applicability for poorly temperature-controlled camera systems and the possibility of ex post facto dark current correction.

Paper Details

Date Published: 21 February 2007
PDF: 8 pages
Proc. SPIE 6501, Sensors, Cameras, and Systems for Scientific/Industrial Applications VIII, 650103 (21 February 2007); doi: 10.1117/12.714784
Show Author Affiliations
Ralf Widenhorn, Portland State Univ. (United States)
Digital Clarity Consultants (United States)
Armin Rest, Cerro Tololo Inter-American Observatory (United States)
Morley M. Blouke, Ball Aerospace & Technologies Corp. (United States)
Richard L. Berry, Digital Clarity Consultants (United States)
Erik Bodegom, Portland State Univ. (United States)
Digital Clarity Consultants (United States)


Published in SPIE Proceedings Vol. 6501:
Sensors, Cameras, and Systems for Scientific/Industrial Applications VIII
Morley M. Blouke, Editor(s)

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