Omnet projects in New South Wales:
Omnet projects in New South Wales For example, in regions of the ultrasound image where no clutter is omnet projects in New South Walespresent, rejection 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, omnet projects in New South Walessingular value-based, and manual observation-based methods.
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 omnet projects in New South Walesuser’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 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 omnet projects in New South Walesin better approximate stationarity and basis functions can better adapt to local 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 omnet projects in New South Walesfunctions. The mean frequencies of each basis function are
computed using the lag-one autocorrelation estimation, and basis functions are rejected when their mean omnet projects in New South Walesfrequencies are within the assumed bandwidth of clutter. Yu and Lovstakken have also examined adaptive weightings based on the spectrum of eigenvalues.