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Optical Engineering

Signal-to-noise ratio, contrast-to-noise ratio, and exposure time for imaging systems with photon-limited noise
Author(s): Robert L. Lucke; R. A. Kessel
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Paper Abstract

We present simple, mathematically tractable definitions of signal-to-noise ratio (SNR), contrast, and contrast-to-noise ratio (CNR) for imaging systems when photon-counting statistics are the dominant source of noise. These definitions lead to a simple expression for CNR that is convenient for comparing images taken under different conditions and/or in different wave bands. Furthermore, this real-space CNR is directly proportional to the SNR in Fourier space. The sampling factor Q with which a focal plane array records an image is shown to be a primary determinant of exposure time and of SNR. If Q is known (or assumed), the f-number, resolution, and pixel size are not required.

Paper Details

Date Published: 1 May 2006
PDF: 6 pages
Opt. Eng. 45(5) 056403 doi: 10.1117/1.2205850
Published in: Optical Engineering Volume 45, Issue 5
Show Author Affiliations
Robert L. Lucke, Naval Research Lab. (United States)
R. A. Kessel, Naval Research Lab. (United States)

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