Company Events Academic NI Developer Zone Support Solutions Products & Services Contact NI MyNI

WA Multiscale Peak Detection VI

Owning Palette: Feature Extraction VIs

Installed With: Advanced Signal Processing Toolkit

Uses multiresolution wavelet analysis to detect peaks or valleys in a signal. Wire data to the signal input to determine the polymorphic instance to use or manually select the instance.

Details  Examples

Use the pull-down menu to select an instance of this VI.

WA Multiscale Peak Detection (waveform)

peaks/valleys specifies whether this VI looks for peaks or valleys in the signal. The default is peaks.
signal specifies the input signal.
threshold specifies the threshold this VI uses to reject peaks or valleys of a particular size. If this VI looks for peaks, this VI ignores peaks with a peak amplitude less than threshold. If this VI looks for valleys, this VI ignores valleys with a valley amplitude greater than threshold.
width specifies the width, in number of samples, of the peaks or valleys. This 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.
initialize? specifies whether to initialize the internal state of the block of data to zero. The default is TRUE. When the value is TRUE, this VI initializes the internal state to zero and processes one block of data. When the value is FALSE, this VI initializes the internal states to the final states by using the previous call to this VI instance.To process consecutive blocks of data, set initialize? to TRUE for the first block and FALSE for all other blocks of data.
num of peaks returns the number of peaks this VI detects.
location returns the locations of the peaks this VI detects.
amplitude returns the amplitudes of the peaks this VI detects.
peak plot returns the input signal and the peaks this VI detects. You can plot this information on an XY graph.
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 Peak Detection (array)

peaks/valleys specifies whether this VI looks for peaks or valleys in the signal. The default is peaks.
signal specifies the input signal.
threshold specifies the threshold this VI uses to reject peaks or valleys of a particular size. If this VI looks for peaks, this VI ignores peaks with a peak amplitude less than threshold. If this VI looks for valleys, this VI ignores valleys with a valley amplitude greater than threshold.
width specifies the width, in number of samples, of the peaks or valleys. This 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.
initialize? specifies whether to initialize the internal state of the block of data to zero. The default is TRUE. When the value is TRUE, this VI initializes the internal state to zero and processes one block of data. When the value is FALSE, this VI initializes the internal states to the final states by using the previous call to this VI instance.To process consecutive blocks of data, set initialize? to TRUE for the first block and FALSE for all other blocks of data.
num of peaks returns the number of peaks this VI detects.
location returns the locations of the peaks this VI detects.
amplitude returns the amplitudes of the peaks this VI detects.
peak plot returns the input signal and the peaks this VI detects. You can plot this information on an XY graph.
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 Peak Detection Details

This VI executes the following steps to detect peaks by using a wavelet-based method.

  1. Performs undecimated discrete wavelet decomposition with the biorthogonal wavelet bior3_1 on the input signal. The width input controls the decomposition level.
  2. Searches for zero-crossing points in the detail coefficients at all levels.
  3. Selects the zero-crossing points at the largest scale as the coarse estimation of the real peaks.
  4. Searches the finer scale for the corresponding nearest zero-crossing point for each detected point.
  5. Repeats step 4 until this VI reaches the finest scale, which is the first level.

Examples

Refer to the following VIs for examples of using the WA Multiscale Peak Detection VI:

  • Breakdown Point Detection VI: labview\examples\Wavelet Analysis\WAApplications.llb
  • ECG Heart Rate Monitor (Online) VI: labview\examples\Wavelet Analysis\WAApplications.llb
  • ECG QRS Complex Detection VI: labview\examples\Wavelet Analysis\WAApplications.llb
  • Peak Detection (Wavelet vs. Normal) VI: labview\examples\Wavelet Analysis\WAGettingStarted.llb

Resources
 

Your Feedback! poor Poor  |  Excellent excellent   Yes No
 Document Quality? 
 Answered Your Question? 
Add Comments 1 2 3 4 5 submit