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Owning Palette: Feature Extraction VIs

Installed With: Advanced Signal Processing Toolkit

Detects ridges by extracting peaks of each row of signal.

Details  Example

	local threshold specifies the method to use to choose the threshold. The default is FALSE, which indicates that the VI uses the global threshold. If local threshold is TRUE, the VI sets the threshold for each row of the signal.
	signal is 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 of the peaks of each row of signal. The unit of width is in samples, and the VI coerces the value to a power of 2.
	error in describes error conditions that occur before this VI or function runs. The default is no error. If an error occurred before this VI or function runs, the VI or function passes the error in value to error out. This VI or function runs normally only if no error occurred before this VI or function runs. If an error occurs while this VI or function runs, it runs normally and sets its own error status in error out. Use the Simple Error Handler or General Error Handler VIs to display the description of the error code. Use error in and error out to check errors and to specify execution order by wiring error out from one node to error in of the next node. status is TRUE (X) if an error occurred before this VI or function ran or FALSE (checkmark) to indicate a warning or that no error occurred before this VI or function ran. The default is FALSE. code is the error or warning code. The default is 0. If status is TRUE, code is a nonzero error code. If status is FALSE, code is 0 or a warning code. source specifies the origin of the error or warning and is, in most cases, the name of the VI or function that produced the error or warning. The default is an empty string.
	ridge contains the ridges the 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. If error in indicates that an error occurred before this VI or function ran, error out contains the same error information. Otherwise, it describes the error status that this VI or function produces. Right-click the error out front panel indicator and select Explain Error from the shortcut menu for more information about the error. status is TRUE (X) if an error occurred or FALSE (checkmark) to indicate a warning or that no error occurred. code is the error or warning code. If status is TRUE, code is a nonzero error code. If status is FALSE, code is 0 or a warning code. source describes the origin of the error or warning and is, in most cases, the name of the VI or function that produced the error or warning.

WA Multiscale Ridge Detection Details

You usually can characterize the ridges of the 2D input signal by the peaks in each row. Therefore, the 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.

Example

Refer to the Spectrogram Ridge Detection VI in the labview\examples\Wavelet Analysis\WAGettingStarted.llb for an example of using the WA Multiscale Ridge Detection VI.