While acquiring/collecting physiological data it becomes extremely relevant to annotate or highlight specific events that occur during signal acquisition.
In this tutorial, you will learn how to use the Event Annotation add-on to highlight events & signal segments both during the acquisition and in post-processing.
Step 1: How to activate the Add-On
Activate the free Manual Measurements add-on for use in the real-time and visualisation modes using the instructions below. Note that this step is only required when using the add-on for the first time.
- Open the OpenSignals help menu
- In the REAL TIME PLUGINS list, check the checkbox next to Events Annotations to activate the add-on for the real-time acquisition mode
- In the POST-PROCESSING PLUGINS list, check the checkbox next to the Events Annotations to activate the add-on for the visualization mode (note this step is not highlighted in the screenshot above)
Step 2: How to access the Add-On
The following instructions are applicable for both the real-time acquisition mode as for the visualisation mode.
1. Open the add-ons panel using the add-on icon:
2. Select the EVENTS ANNOTATION add-on from the tabs of available add-ons at the top of the add-on panel.
Note for macOS users using macOS (10.15) Catalina and earlier In order to use this add-on's functionality you need to add OpenSignals to the accessibility whitelist. Find out how to to this here: https://mizage.com/help/accessibility.html
Step 3: How to annotate events during the acquisition
Setup your device for acquisition and start a real-time acquisition by clicking on the red record button.
Access the add-on as shown in Step 2 of this guide.
The annotations can be made either for all acquisition devices and all channels or for specific devices and channels only.
Start by selecting the device and channels for which you would like to annotate events. This setting can be changed as needed throughout the acquisition.
After defining the device and channels to which the current event will be applied, a color and single-character label can be specified using the following controls.
💡 Useful Tipp The selected annotation character also acts as hotkey for annotating events with your keyboard throughout the acquisition!
And that’s it for the acquisition mode! Your annotations will be stored in a separate .txt file in the same location where your signal acquisition is being stored.
Step 4: How to annotate events after the acquisition
Enter the visualisation mode using the replay icon in the main interface.
Access the add-on as shown in Step 2: How to access the add-on of this guide.
Step 4.1: Loading annotations (made during the acquisition)
In the visualisation mode, the add-on opens provides additional controls for you to use if you made any annotation during the signal acquisition:
- Open Annotations File: open your annotation files that belongs to your acquisition
- Draw Annotations: draw the annotations
- Reset Annotation File: remove all drawn annotations
Step 4.2: Adding new annotations in post-processing
Annotations can also be added after the acquisition in post-processing. As in the acquisition mode, annotations can be defined by color and single-character label using the following controls.
The screenshot below shows you the various results that can be achieved with these configurations.
Once you’ve set the color (1), the label (2), and added the annotation (3), you can either add an annotation that marks a specific moment in your acquisition (3a) or drag an drop to highlight signal segments with the specified color and label (3b).
Once you’ve completed your signal annotation, click on the SAVE EVENTS FILE button to save your results.
This generated file can be opened using the Open Annotation File button to reload your annotations the next time you’re working with your acquisition.