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PeakFindingWavelet

Find all peaks in the given data along a given axis.

This method uses a continuous wavelet based approach to be able to identify multiple peaks of various shapes and sizes. Note that there is also an alternative method that is based on contours, which may be easier to use or give more predictable results. By default, the offset is returned as the index of the element, counting from zero for the first element. However, in the special case that the node is applied over the time axis, it is possible to measure the offset instead in seconds, and one may also look up the position in seconds from the time axis (e.g., relative to whatever is 0 in the time axis). One can also optionally account for the delay of previous filter nodes, to the extent that the data is annotated with it. Version 1.0.2

Ports/Properties

indata

Input data.

  • verbose name: Indata
  • default value: None
  • port type: DataPort
  • value type: Packet (can be None)
  • data direction: IN

latencies

Output peak latencies.

  • verbose name: Latencies
  • default value: None
  • port type: DataPort
  • value type: Packet (can be None)
  • data direction: OUT

amplitudes

Output peak amplitudes.

  • verbose name: Amplitudes
  • default value: None
  • port type: DataPort
  • value type: Packet (can be None)
  • data direction: OUT

axis

Axis along which to find the peak. This axis will drop out of the data and be replaced by a one-element feature axis.

  • verbose name: Find Peak Along Axis
  • default value: time
  • port type: ComboPort
  • value type: str (can be None)

negative

Apply to negative peaks. If checked, the smallest element will be searched, instead of the largest.

  • verbose name: Find Negative Peaks
  • default value: False
  • port type: BoolPort
  • value type: bool (can be None)

unit

Unit of measurement to use, depending on axis that the peak is searched along. Using seconds here works only if the operation is performed along the time axis, and if the axis has a sampling rate set.

  • verbose name: Unit Of Measurement
  • default value: samples
  • port type: EnumPort
  • value type: str (can be None)

wavelet

Type of wavelet to use for matching.

  • verbose name: Wavelet
  • default value: ricker
  • port type: EnumPort
  • value type: str (can be None)

min_width

Minimum peak width. Expressed in the selected unit of measurement (seconds or samples). For other units (e.g., Hz), this is still measured in samples.

  • verbose name: Min Width
  • default value: 5
  • port type: FloatPort
  • value type: float (can be None)

max_width

Maximum peak width. Expressed in the selected unit of measurement (seconds or samples). For other units (e.g., Hz), this is still measured in samples.

  • verbose name: Max Width
  • default value: 15
  • port type: FloatPort
  • value type: float (can be None)

num_widths

Number of intermediate widths to consider. The algorithm will separately scan for a number of intermediate widths between min_width and max_with. Choosing a finer resolution here may improve the accuracy of peak finding, but at increased computational cost.

  • verbose name: Num Widths
  • default value: 10
  • port type: IntPort
  • value type: int (can be None)

max_count

Maximum number of peaks to find. If more peaks are found, the ones with the highest amplitude will be kept.

  • verbose name: Max Count
  • default value: None
  • port type: IntPort
  • value type: int (can be None)

subtract_filter_delay

Subtract filter delay (time axis only). Note that this is most reliable when used with only linear-phase filters (e.g., FIR filter without minimum phase option), since otherwise the delay will depend on the frequency content of the signal.

  • verbose name: Subtract Filter Delay
  • default value: False
  • port type: BoolPort
  • value type: bool (can be None)

account_for_time_axis

Look up latency from the time axis. If unchecked, the lantency will be computed relative to the beginning of the data segment, but if checked, it will be relative to whatever is 0.0 in the time axis (and would even work with irregularly sampled data).

  • verbose name: Respect Time Axis
  • default value: False
  • port type: BoolPort
  • value type: bool (can be None)

update_on_streaming

Update on streaming data. If enabled (default), then this node will update its output measure on every chunk, whether it is marked as streaming or not. If False, then it will only update on non-streaming, chunks, such as calibration data.

  • verbose name: Update On Streaming Data
  • default value: True
  • port type: BoolPort
  • value type: bool (can be None)

min_snr

Minimum signal-to-noise ratio.

  • verbose name: Min Snr
  • default value: 1
  • port type: FloatPort
  • value type: float (can be None)

noise_percentile

Percentile of where the noise floor lies.

  • verbose name: Noise Percentile
  • default value: 10
  • port type: FloatPort
  • value type: float (can be None)

set_breakpoint

Set a breakpoint on this node. If this is enabled, your debugger (if one is attached) will trigger a breakpoint.

  • verbose name: Set Breakpoint (Debug Only)
  • default value: False
  • port type: BoolPort
  • value type: bool (can be None)

metadata

User-definable meta-data associated with the node. Usually reserved for technical purposes.

  • verbose name: Metadata
  • default value: {}
  • port type: DictPort
  • value type: dict (can be None)