3D Topography

Summary

Doc_BoxAlgorithm_3DTopography.png
  • Plugin name : 3D Topography
  • Version : 1.0
  • Author : Yann Renard
  • Company : Mensia Technologies SA
  • Short description : The input is mapped to a 3D model of the scalp, using a color gradient and interpolation.
  • Documentation template generation date : Nov 2 2017

Description

The 3D Topography box combines EEG measures with topological information. The input, being signal, spectrum, or any other metric, is mapped to a 3D model of the scalp. This box is provided with a preconfigured channel localisation file that contains the cartesian coordinates of every electrode positions of the extended 10-20 system. The mapping is done according to these coordinates using spherical spline interpolation. A color gradient is used to display the information, and can be customized at will to easily enhance or smooth the contrasts. Several presets are available, to match the gradients you may be already familiar with when using existing softwares such as Matlab or Elan. The color gradient is mapped to the current data scale, centered around 0.

The 3D Topography box shares common concepts and settings with the other boxes in the Mensia Advanced Visualization Toolset. Additional information are available in the dedicated documentation pages:

Inputs

1. Matrix

The box input can be a streamed matrix or any derived stream (Signal, Spectrum, Feature Vector). Please set the input type according to the actual stream type connected.

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

Settings

1. Channel Localisation

The channel localisation file containing the cartesian coordinates of the electrodes to be displayed. A default configuration file is provided, and its path stored in the configuration token ${AdvancedViz_ChannelLocalisation}.

  • Type identifier : Filename (0x330306dd, 0x74a95f98)
  • Default value : [ ${AdvancedViz_ChannelLocalisation} ]

2. Gain

Gain (floating-point scalar factor) to apply to the input signal before display.

  • Type identifier : Float (0x512a166f, 0x5c3ef83f)
  • Default value : [ 1 ]

3. Caption

Label to be displayed on top of the visualization window.

  • Type identifier : String (0x79a9edeb, 0x245d83fc)
  • Default value : [ ]

4. Color

Color gradient to use. This setting can be set manually using the color gradient editor. Several presets exist in form of configuration tokens ${AdvancedViz_ColorGradient_X}, where X can be:

  • Matlab or Matlab_Discrete
  • Icon or Icon_Discrete
  • Elan or Elan_Discrete
  • Fire or Fire_Discrete
  • IceAndFire or IceAndFire_Discrete

The default values AdvancedViz_DefaultColorGradient or AdvancedViz_DefaultColorGradient_Discrete are equal to </t>Matlab and Matlab_Discrete.

An example of topography rendering using these color gradients can be found here.

  • Type identifier : (0x3d3c7c7f, 0xef0e7129)
  • Default value : [ ${AdvancedViz_DefaultColorGradient} ]

Examples

In the following example, we compute the band power of the signal in the 8-15 Hz frequency range, and average it over the last 32 epochs received.

You can find a commented scenario in the provided sample set, the scenario file name is {3DTopography.mxs}.

3DTopography_Example.png
Example of scenario using the 3D topography

Miscellaneous