Noise filtration

The previous method supposes complete knowledge of the system and depends on the measurement quality of instruments (errors, availability), leading to severe effects on the accuracy of the on-line estimates. Therefore, a good noise filtration algorithm (like the Kalman filter or derivative) should be employed to improve the reliability of the estimated values before their use. 

The OCR process is divided into two steps separation of each character into a matrix and the recognition of each matrix. Character separation is performed because characters are often overlapped, and therefore recognition is difficult or unreliable. Each separated matrix undergoes a noise filtration to eliminate isolated on-pixels. The character recognition is achieved by feature extraction of the refined matrix. 

Pizurica, A. and Philips, W. and Lemahieu, I. and Acheroy, M., A versatile wavelet domain noise filtration technique for medical imaging ,IEEE Transactions on Medical Imaging 2003, pp. 323— 331... 

This necessitates plant capable of control of temperature by being able to add or subtract heat from the air and control of humidity by being able to add or subtract moisture. The system also comprises fan(s), filtration, and a distribution system and may include noise control. Other terms such as cooling or comfort cooling may be met and these can be taken to mean an ability to lower the temperature of the air by refrigeration but without full control of humidity. Moisture may be removed as an incidental characteristic of the cooling coil. The term air conditioning is sometimes used where control of humidity is not included. It is essential to employ clear specifications of performance. 

Centrifuges, 22 288. See also Hydrocyclones basket, 11 389-390, 391 filtration equipment, 5 542-548 fixed-bed, 11 389-391 materials of construction and operational stress, 5 522-524 moving-bed, 11 391-392 noise, 5 524-525... 

Figure 12.6 Two sections of the proton NMR spectrum for a protein product after the protein has been removed. Only the formulation buffer (25 mM citrate) and a small amount ( 1 pg/ml) of residual Tris (a component of the penultimate buffer used in the recovery process prior to the final UF/DF formulation step) are observed after the filtration. The signal-to-noise ratio of Tris is about 70. The absence of any other significant proton NMR signals provides compelling evidence for good clearance of any other small proton-containing molecule impurities.

After the second layer the time courses of A, (t) are filtrated by the threshold value UiH and gradually settled to a two-state, having the values 0 and 1.0 only, and having a higher signal-to-noise ratio. 

The low frequency baseline noise of the viscometer can be substantially reduced by careful filtration of samples and regular checking and maintenance of column end fittings and fractional sections of tubing in the system. Figure 5 shows the effect of column screen replacement on the stability of the baseline signal at a flow rate of 1.0 ml/min. 

Greater spatial resolution Better suited than conventional SEM for automation Better signal-to-noise ratio for submicron particulates Subject to filtration artifacts... 

From Fig. 3.15 we can note that, by analogy to the 2 bar constant pressure case, example FIS shows a new special case where we have positive and small negative values in the concentrated suspension flow rate at the plant exit. This result can be explained by the background noise in the measurement of the flow of suspension. Nevertheless, the mean value of the flow rate is small but positive. If the efficiency of the filtration at constant pressure is given by the solid concentration ratio between the exit and fresh suspensions, then, as shown in Fig. 3.13, the ratio is always lower than 2 for operation case F2/1.6. For cases FI and FIS, this ratio increases permanently, non-uniformly and attains values over 12 g/1 in the proximity of the complete clogging state. 

A second potential problem concerns aliased noise due to the increased spectral width. Digital filters, when combined with analog ones (Section 2-4c), do an excellent job of keeping unwanted noise (and signals, too ) from aliasing into the selected spectral window. This very efficient filtration can become a liability, however, if spectral widths are not carefully chosen, because the presence of signals that have been accidentally left outside of the spectral window is not revealed by the appearance of aliased resonances. 

Figure 4. A block diagram of cavitation indicators (a) and spectrum patterns of cavitation noises of aluminum melts of different purities with the ultrasonic treatment at 18 kHz with A = 20 pm at 720 °C (b). I. Noise level at different AI2O3 content (mass %) II. A melt of a V95pch grade alloy before (1) and after (2) fine filtration.

A compressor should also match the other typical requirements of a road vehicle, in particular noise, cost reduction, and compactness. A further consideration derives from the quality of oxidant required by the stack. The air must be very clean since the presence of few small oil droplets or traces of chemical contaminants could damage dramatically the fuel cells, reducing their efficiency and durability. Therefore, PEMFC systems require oil-free compressors or air filtration for removing particulate and contaminants (sulfurs, salts, CO, and hydrocarbons). 

Which agrees with the result obtained using the irreducible tensor formalism.34 The triple-quantum filtration pulse sequence, applied to a spin- quadrupolar nucleus, produces almost exactly the same result as does the double-quantum filtration sequence, except for two differences. The double-quantum relaxation rate is faster than the triple-quantum relaxation rate, and the triple-quantum FID is a factor of 1.5 larger than the double-quantum FID.34 The triplequantum filter will thus require less than half the number of acquisitions to equal the signal-to-noise of the double-quantum sequence. 

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