SNR Figure of Merit

Rearrangement of Eq. (4.15) permits definition of an SNR figure of merit (f sNR). which is useful for comparing spectrometer performance (2). It is generally more useful than the figure of merit for signal defined in Eqs. (3.10) and (3.11). Equation (4.24) defines Fsnr based on Eq. (4.15). 

In principle, the signal and signal/noise ratio (SNR) figures of merit discussed in Sections 3.4 and 4.4 can be applied to fiber-optic sampling. Equation (3.11)... 

The observed F depends on several variables, particularly the fiber numerical aperture, sample depth, interfiber distances, filter losses, and so fourth Similarly, an SNR figure of merit may be determined empirically, which would Incorporate SNR degradation due to fiber background. Equation (12.7) for is identical to Eq. (4.25), and both are based on experimetnally determined variables ... 

The performance of a lifetime detection system can be conveniently quantified by a figure-of-merit F, which is defined as the ratio of the SNR in a lifetime measurement and the SNR in an intensity measurement both carried out with the same number of photons. Based on this definition, F can be written as ... 

We have utilized a performance metric that is suitable for comparing the imaging performance for large spatial areas of two different systems. The figure of merit we employ is the number of pixels per minute (pixpm) that can be recorded for specified data quality (SNR of absorbance spectra) at defined spectral and spatial resolution, apodization and wavelength bandpass. Since the SNR of recorded data can be anticipated to scale with the data acquisition time (as V ), the adjustment allows for easy comparisons of detectors with different sizes and performance. Consider the comparison between two detectors in terms of the ratio of their pixpm output as... 

In three-way calibration, as with two-way calibration, the figures of merit are similarly derived from the three-way NAS. Assuming that all calculations are performed at unit analyte concentration, the selectivity, sensitivity, and SNR are the magnitude of the NAS divided by the magnitude of the analyte signal, concentration, and noise, respectively. Mathematically, these equations can be found from... 

The expression for Raman signal from Chapter 3 may be combined with Eq. (4.11) to arrive at the dependence of experimental SNR on various sample and measurement variables. SNR is a generally more important indicator of the utility of the measurement than raw signal, since SNR determines the detection limit and overall information content. In addition, SNR may be compared for spectra with quite different intensity units, such as dispersive/CCD and FT-Raman instruments. In the remainder of this chapter, we will derive SNR expressions for several situations, and define a figure of merit for SNR. 

The figures of merit, Fs and f snr. defined in Chapters 3 and 4, permit comparison of spectrometers for a given sample and laser power. Equation 4.29 shows... 

For assessing the performance of the above-described wavelet de-noising algorithm a quantitative evaluation of the reconstruction was carried out. As figures of merit, the MSE (Eq. (6)) and the SNR (Eq. (8)) were used. Wavelet de-noising was compared with the optimal MSE Wiener filter [2]. Wiener filter reconstructions were calculated using the wiener function from the... 

In other words, a single-exponential fluorescence lifetime can ideally be derived from a given number of photons per pixel with the same relative uncertainty as the intensity [187, 274]. The efficiency of a lifetime technique is often characterised by the Figure of Merif [19, 84, 274, 409]. The figure of merit, F, compares the SNR (signal-to-noise ratio) of an ideal recording device with the SNR of the technique under consideration ... 

The SNR is a figure of merit that is frequently cited in product literature. Values are often reported as peak-to-peak absorbance measured for a given spectrometer configuration over a specified time period and spectral range and at a specified spectral resolution. The SNR varies in direct proportion to the instrument throughput, source spectral radiance, detector D, and spectral resolution [35]. SNR also increases with the square root of measurement time which... 

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