Ns2 simulation in Illinois:
Ns2 simulation in Illinois For example, in regions of the ultrasound image where no clutter is present, rejection ns2 simulation in Illinois of the first PCA basis functions will have the unwanted affect of attenuating the desirable source signal of interest Due to these limitations, different strategies have been proposed for adaptively determining t he weighting coefficients.
These can be categorized into frequency-based, singular value-based, and manual observation-based methods. ns2 simulation in Illinois Manual observation strategies generally have involved computing one set of basis functions for the entire ultrasound image, inspecting these basis functions, and then setting based on the user’s interpretation of these basis functions
While adaptive, this strategy is limited in its inability to be applied in real-time. Moreover, determining a new ns2 simulation in Illinois set of PCA basis functions for every spatial location of the image, instead of a single set of basis functions for the entire image,
is advantageous as observations in better approximate stationarity and basis functions can better adapt to localns2 simulation in Illinois spatial variations in the ultrasound image. In the frequency-based approach proposed by Yu and Lovstakken weighting coefficients are determined adaptively from the frequency content of the individual PCA basis functions.
The mean frequencies of each basis function are computed using the lag-one autocorrelation estimation, and ns2 simulation in Illinoisbasis functions are rejected when their mean frequencies are within the assumed bandwidth of clutter. Yu and Lovstakken have also examined adaptive weightings based on the spectrum of eigenvalues.