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Owning Palette: Feature Extraction VIs
Requires: Advanced Signal Processing Toolkit
Detects ridges by extracting peaks of each row of a signal.
|local threshold? specifies the method to use to choose the threshold. If local threshold? is TRUE, this VI sets the threshold for each row of the signal. If local threshold? is FALSE, this VI uses the global threshold. The default is FALSE.|
|signal specifies the 2D input signal.|
|threshold ratio specifies the threshold to reject small peaks. The threshold equals (Max–Min)×threshold ratio+Min, where Max and Min are the maximum and minimum value of the signal, respectively. threshold ratio must be between 0 and 1.|
|width specifies the width, in samples, of the peaks of each row of signal. This VI coerces the value to a power of 2.|
|error in describes error conditions that occur before this node runs. This input provides standard error in functionality.|
|ridge returns the ridges this VI detects. ridge has the same dimensions as signal. The values in ridge are 0 or 1, where 1 indicates that a peak exists at the location along the row direction. Use an intensity graph to display the ridges.|
|error out contains error information. This output provides standard error out functionality.|
You usually can characterize the ridges of the 2D input signal by the peaks in each row. Therefore, this VI carries out the robust peak detection using the wavelet-based method on each row. All detected peaks form the ridges. For signals with ridges parallel to the row direction, you can detect the ridges from the transposed 2D signals.
Refer to the Spectrogram Ridge Detection VI in the labview\examples\Wavelet Analysis\WAGettingStarted directory for an example of using the WA Multiscale Ridge Detection VI.