Crossing Detector

Emits a TTL event when a continuous channel crosses a specified threshold level. Each Crossing Detector can only process one input channel at a time, but multiple detectors can be placed in series to trigger on as many channels as desired.

Installation

This plugin can be added via the Open Ephys GUI Plugin Installer. To access the Plugin Installer, press ctrl-P or ⌘P from inside the GUI. Once the installer is loaded, browse to the "Crossing Detector" plugin and click "Install."

Usage

Plugin Editor

• When the Channel that is selected Rises and/or Falls across the threshold level (specified in the visualizer window), an event is triggered on the TTL_OUT line.

• TIMEOUT_MS controls the minimum time between two consecutive events (i.e. for this number of milliseconds after an event fires, no more crossings can be detected).

Visualizer Window

• Threshold type:

  • Constant (default) - the threshold is a constant value.

  • Random - the plugin randomly chooses a new threshold for each event, based on a uniform distribution

  • Continuous channel - the input channel is compared with a second continuous channel on a sample-by-sample basis, to allow the threshold to change dynamically

• Event criteria:

  • Cross-threshold jump size limit (does not fire an event if the difference across threshold is too large in magnitude; useful for filtering out wrapped phase jumps, for example)

  • Sample voting (make detection more robust to noise by requiring a larger span of samples before or after t0 to be on the correct side)

  • Ignore crossings at the end of a buffer

• Event duration (in ms) - the delay until the "OFF" event after an "ON" event is triggered

Building from source

First, follow the instructions on this page to build the Open Ephys GUI.

Important: This plugin is intended for use with the latest version of the GUI (0.6.0 and higher). The GUI should be compiled from the main branch, rather than the former master branch.

Then, clone this repository into a directory at the same level as the plugin-GUI, e.g.:

Code
├── plugin-GUI
│   ├── Build
│   ├── Source
│   └── ...
├── OEPlugins
│   └── crossing-detector
│       ├── Build
│       ├── Source
│       └── ...

Windows

Requirements: Visual Studio and CMake

From the Build directory, enter:

cmake -G "Visual Studio 17 2022" -A x64 ..

Next, launch Visual Studio and open the OE_PLUGIN_crossing-detector.sln file that was just created. Select the appropriate configuration (Debug/Release) and build the solution.

Selecting the INSTALL project and manually building it will copy the .dll and any other required files into the GUI's plugins directory. The next time you launch the GUI from Visual Studio, the Crossing Detector plugin should be available.

Linux

Requirements: CMake

From the Build directory, enter:

cmake -G "Unix Makefiles" ..
cd Debug
make -j
make install

This will build the plugin and copy the .so file into the GUI's plugins directory. The next time you launch the compiled version of the GUI, the Crossing Detector plugin should be available.

macOS

Requirements: Xcode and CMake

From the Build directory, enter:

cmake -G "Xcode" ..

Next, launch Xcode and open the crossing-detector.xcodeproj file that now lives in the “Build” directory.

Running the ALL_BUILD scheme will compile the plugin; running the INSTALL scheme will install the .bundle file to /Users/<username>/Library/Application Support/open-ephys/plugins-api. The Crossing Detector plugin should be available the next time you launch the GUI from Xcode.

Attribution

This plugin was originally developed by Ethan Blackwood and Mark Schatza in the Translational NeuroEngineering lab at the University of Minnesota. It is now being maintained by the Allen Institute.