Signal-to-noise ratio, contrast-to-noise ratio, and exposure time for imaging systems with photon-limited noise

2006 ◽  
Vol 45 (5) ◽  
pp. 056403 ◽  
Author(s):  
Robert L. Lucke
Keyword(s):  
Exposure Time ◽  
Signal To Noise Ratio ◽  
Imaging Systems ◽  
Signal To Noise ◽  
Noise Ratio

scholarly journals Photometric Characteristics of Data from the Hubble Space Telescope Goddard-High Resolution Spectrograph

1988 ◽  
Vol 132 ◽  
pp. 35-38
Author(s):  
Dennis C. Ebbets ◽  
Sara R. Heap ◽  
Don J. Lindler
Keyword(s):  
Exposure Time ◽  
Hubble Space Telescope ◽  
Signal To Noise Ratio ◽  
Scattered Light ◽  
Signal To Noise ◽  
Space Telescope ◽  
Additional Noise ◽  
Reduction Strategies ◽  
Noise Ratio

The G-HRS is one of four axial scientific instruments which will fly aboard the Hubble Space Telescope (ref 1,2). It will produce spectroscopic observations in the 1050 A ≤ λ ≤ 3300 A region with greater spectral, spatial and temporal resolution than has been possible with previous space-based instruments. Five first order diffraction gratings and one Echelle provide three modes of spectroscopic operation with resolving powers of R = λ/ΔΔ = 2000, 20000 and 90000. Two magnetically focused, pulse-counting digicon detectors, which differ only in the nature of their photocathodes, produce data whose photometric quality is usually determined by statistical noise in the signal (ref 3). Under ideal circumstances the signal to noise ratio increases as the square root of the exposure time. For some observations detector dark count, instrumental scattered light or granularity in the pixel to pixel sensitivity will cause additional noise. The signal to noise ratio of the net spectrum will then depend on several parameters, and will increase more slowly with exposure time. We have analyzed data from the ground based calibration programs, and have developed a theoretical model of the HRS performance (ref 4). Our results allow observing and data reduction strategies to be optimized when factors other than photon statistics influence the photometric quality of the data.

Accurate Measurement of Trace Elements Using an Innovative Fixed Goniometer for a Simultaneous Spectrometer

1994 ◽  
Vol 38 ◽  
pp. 691-698
Author(s):  
K. Kansai ◽  
K. Toda ◽  
H. Kohno ◽  
T. Arai ◽  
R. Wilson
Keyword(s):  
Trace Elements ◽  
Exposure Time ◽  
Background Subtraction ◽  
Signal To Noise Ratio ◽  
Detection Limits ◽  
Background Correction ◽  
Analysis Time ◽  
Signal To Noise ◽  
Noise Ratio ◽  
Selection Of

Advancements in trace clement analysis require improvements in both the signal-to-noise ratio and accurate background correction. With a sequential spectrometer, one can obtain detection limits of around 0.1 ppm for medium to heavy Z elements. Conditions can be individually optimized for each element, for example, selection of filters, collimators, crystals and background subtraction. The disadvantage is that the analysis time may become “long” if many elements are to be analyzed. This long exposure time can lead to the deterioration of some samples.

Optimization of the exposure time of aerospace camera through its signal-to-noise ratio

2008 ◽  
Author(s):  
Yuheng Chen ◽  
Yiqun Ji ◽  
Jiankang Zhou ◽  
Xinhua Chen ◽  
Weimin Shen
Keyword(s):  
Exposure Time ◽  
Signal To Noise Ratio ◽  
Signal To Noise ◽  
Noise Ratio
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