Zero-Crossing Detector

Summary

Doc_BoxAlgorithm_ZeroCrossingDetector.png
  • Plugin name : Zero-Crossing Detector
  • Version : 1.0
  • Author : Quentin Barthelemy
  • Company : Mensia Technologies SA
  • Short description : Detects zero-crossings of the signal
  • Documentation template generation date : Nov 2 2017

Description

Detects zero-crossings of the signal for each channel, with 1 for positive zero-crossings (negative-to-positive), -1 for negatives ones (positive-to-negative), 0 otherwise. For all channels, stimulations mark positive and negatives zero-crossings. For each channel, the rythm is computed in events per min.

Using an hysteresis thresholding, this box detects the zero-crossings of the input, operating on all channels.

Inputs

1. Input signal

The input signal $ X \in \mathbb{R}^{C \times N} $, composed of $ C $ sensors and $ N $ samples.

  • Type identifier : Signal (0x5ba36127, 0x195feae1)

Outputs

1. Zero-crossing signal

Zero-crossing signal $ Z \in \mathbb{R}^{C \times N} $, composed of $ C $ sensors and $ N $ samples. It is defined as 1 for positive zero-crossings (negative-to-positive), -1 for negatives ones (positive-to-negative), 0 otherwise.

  • Type identifier : Signal (0x5ba36127, 0x195feae1)

2. Zero-crossing stimulations

For all channels, stimulations mark positive and negatives zero-crossings.

  • Type identifier : Stimulations (0x6f752dd0, 0x082a321e)

3. Events rythm (per min)

For each channel, the rythm of zero-crossings is computed in events per min.

  • Type identifier : Streamed matrix (0x544a003e, 0x6dcba5f6)

Settings

1. Hysteresis threshold

This setting defines the value $ t $ of the hysteresis threshold, to provide a robust detection.

ZeroCrossingDetector_thresholding.png
Difference between naive and hysteresis sign thresholding
  • Type identifier : Float (0x512a166f, 0x5c3ef83f)
  • Default value : [ 0.01 ]

2. Rythm estimation window (in sec)

This setting defines the length of the time window for the rythm estimation.

  • Type identifier : Float (0x512a166f, 0x5c3ef83f)
  • Default value : [ 10 ]

3. Negative-to-positive stimulation

This setting defines the stimulation id for negative-to-positive crossings.

  • Type identifier : Stimulation (0x2c132d6e, 0x44ab0d97)
  • Default value : [ OVTK_StimulationId_ThresholdPassed_Positive ]

4. Positive-to-negative stimulation

This setting defines the stimulation id for positive-to-negative crossings.

  • Type identifier : Stimulation (0x2c132d6e, 0x44ab0d97)
  • Default value : [ OVTK_StimulationId_ThresholdPassed_Negative ]

Examples

Miscellaneous