Signal preprocessing

When the signal preprocessing is finished, additional pretreatments can be carried out to enhance certain properties of the image data set. Again, the spectra in an image can be subjected to any data pretreatment used in traditional spectroscopic data sets, with the choice depending on the spectral structure and the goal of the... 

Signal preprocessing (amplification, filtering, A/D conversion, segmentation, signal transformation)... 

Pedrotti, M., Lei, s., Dzaack, j. Rotting, M. 2011. A data-driven algorithm for offline pupil signal preprocessing and eyeblink detection in low-speed eye-tracking protocols. Behavior Research Methods, 43, 372-383. 

Linear-interpoUUed of heart period signal Preprocessing technique of linear-interpolated heart period values is obtain by linear interpolation of the heart period before it is resampled at 4Hz. 

Fig. 4a shows a characteristic narrow banded signal (860 kHz center frequency) from a flat steel surface (reference signal). A steel block was milled in a way that the distance of the upper and graved surface varied from 0 to about 1300 microns (Fig. 5). Moving the probe along the edge (see Fig. 5) about 30 signals have been acquired equidistantly (all 4 mm). Fig. 4b and 4c show two characteristic signals (position 6 and 12). The 30 measured signals have been preprocessed and deconvolved. Fig. 6 shows the evident correlation between measured TOF difference and signal position (depth of milled grave).

Uncertainty in Process Measurements. Sensor measurements are always subject to noise, calibration error, and temporary signal loss, as well as various faults that may not be immediately detected. Therefore, data preprocessing will often be required to overcome the inherent limitations of... 

The data matrix is preprocessed using any signal enhancement technique to obtain the spectroscopic data of greatest interest as it relates to the spatial characteristics of the material or sample surface under study. In this particular case each data point represents the absorbance difference between a no absorbing wavelength for the paper surface and an absorbing wavelength for the transparent ink added to the paper. The difference in... 

Fig. 3. a Raman spectra (preprocessed) this peak predominantly shows formation of product, b Spectral changes over time shown for the wave number of maximum signal (1608 cm 1)... 

MSC Multiplicative signal/scatter correction (preprocessing of NIR data)... 

Prior to data analysis, some preprocessing may be desirable or necessary. Normalization of acquired images to regions that should contain no mRNA (e.g., corpus callosum), which can reduce signal variance (see Ambesi-Impiombato et al., 2003). Algorithms have also been developed that allow the comparison of... 

H. Martens and E. Stark, Extended multiplicative signal correction and spectral interference subtraction new preprocessing methods for near infrared spectroscopy, J. Pharm. Biomed. Anal, 9, 625-35 (1991). 

In the case of the complex analytical signals arising from artificial tongue instruments, a number of preprocessing tools may be employed for three main purposes, namely ... 

Row preprocessing acts on each single signal, independent of the other ones, and the result is the correction of systematic differences among signals. 

Evaluate carefully the most appropriate data preprocessing tools (signal corrections, transforms, compression) in order to minimize the amount of unwanted information. 

Kohler, A., Zimonja, M., Segtnan, V., and Martens, H. (2009). Standard normal variate, multiplicative signal correction and extended multiplicative signal correction preprocessing in biospectroscopy. In "Comprehensive Chemometrics", (S. D. Brown, R. Tauler, and B. Walczak, Eds), Vol. 2, pp. 139-162. Elsevier, Amsterdam. 

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