Amplitude Detector

Module name: AmplitudeDetector

Package: CEAMSModules 7.4.0

Version: 2.0.0

Overview

This plugin detects events based on the absolute signal amplitude. The plugin is flexible, an event can be detected when activity goes above or below the threshold. The threshold can be fixed or adaptive based on a baseline window around the event. The adaptive threshold can be x times the baseline median value or x times the standard deviation of the baseline. When a z-score is used as threshold (x BSL STD), the absolute signal amplitude can be log10 transformed to make them more normally distributed.

Inputs

Input

Format

Default

Description

signals

a list of SignalModel

—
signal.samples : The actual signal data as numpy list
signal.sample_rate : sampling rate of the signal (used to STFT)
signal.channel : current channel label

event_group

string, event group.

—

string, event group.

event_name

string, event label.

—

string, event label.

pad_sec

string

0.5
The padding event (length in second) to add to the beginning and
the end of the originally detected event.

threshold_val

string or a list of float

—
String : the value to threshold to detect events.
list : the value to threshold for each signal included in signals.

threshold_unit

string

fixed

The threshold unit (fixed, x BSL median, x BSL STD or x BSL STD(log10)).

threshold_behavior

string

Above
Above : Event is detected when activity goes above the threshold.
Below : Event is detected when activity goes below the threshold.

baseline_win_len

string

—

(optional) The baseline window length in seconds

art_events

Pandas DataFrame (columns=[‘group’,’name’,’start_sec’,’duration_sec’,’channels’])

—

(optional) Artefact events previously detected

channel_dbg

string

None

Channel label to save and exit detection info.

Outputs

Output

Format

Description

events

Pandas DataFrame

DataFrame events (columns=[‘group’,’name’,’start_sec’,’duration_sec’,’channels’])

det_activity

list of ndarray of n_windows
An array per item of the list signals.
An array is the absolute signal amplitude or the std amplitude value relative to the baseline.

bsl_activity

list of ndarray of n_windows
An array per item of the list signals.
(Optional) MedianSTD amplitude of the baseline window.

Usage in a process

  1. Open Dev Tools -> New process in Snooz.

  2. In the Module Library, find Amplitude Detector under the Detectors category.

  3. Drag the module onto the process canvas.

  4. Connect the required inputs from upstream modules (or set values in the Settings tab).

  5. Connect outputs to downstream modules as needed.

  6. Double-click the module to configure parameters in the Settings tab.

  7. Run the process and inspect results in the Results tab.

Note

For general guidance on building processes with modules, see Explore examples.