Voting Classifier

Summary

• Plugin name : Voting Classifier
• Version : 1.0
• Author : Yann Renard
• Company : INRIA
• Short description : Majority voting classifier. Returns the chosen class.
• Documentation template generation date : Oct 29 2020

Description

Each classifier used as input is assumed to have its own two-class output stream. Mainly designed for P300 scenario use.

The purpose of this simple classifier is to choose between multiple two class classifiers which one mostly fits a condition. For example imagine n states. Each of those states can be either active or inactive. Additionally, imagine you want only one active state at a time. Then you can have n two-class classifiers telling for each state if it is active or not, and a following voting classifier that chooses which of those states is the most active.

Inputs

You can add as many inputs as you need depending on the number of preceeding states.

The inputs of this classifier can be changed to either streamed matrix of stimulations.

In the case you choose stimulations, each active stimulation gives a point to the preceeding state. Both an inactive and a reject stimulation gives no point. Any other stimulation is ignored. After a number of repetitions, the state with the best score is chosen.

In the case you choose streamed matrix, the matrix must have only one element. This element is used as a score coefficient (in place of the simple 1-0 of the previous case). After a number of repetitions, the state with the best score is chosen.

1. Classification result 1

Input stream for the first state.

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

2. Classification result 2

Input stream for the second state.

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

Outputs

1. Classification choice

This output sends a new stimulation as soon as the classifier received the correct number of votes from the preceeding states. The output stimulation is based on the 5th setting of the box. First state being selected would send exactly this stimulation. Second state would send this stimulation + 1 etc.

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

Settings

1. Number of repetitions

This setting tells the box how many votes it needs before choosing. If the box uses stimulations, it must receive either the target or non target stimulation to consider a state has been voted. Additionaly, the box waits each state to be voted the correct number of times to take a decision.

• Type identifier : Integer (0x007deef9, 0x2f3e95c6)
• Default value : [ 12 ]

2. Target class label

If the box uses stimulations, this settings tells what stimulation reflects that the state is active.

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

3. Non target class label

If the box uses stimulations, this settings tells what stimulation reflects that the state is inactive.

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

4. Reject class label

In case no choice can be made (for example, there are more than one state with the highest score), the voting classifier can choose to reject the vote and send a specific stimulation for this. This is more likely to happen when the box works on stimulation better than streamed matrix. You can force this box to choose using the 6th setting.

• Type identifier : Stimulation (0x2c132d6e, 0x44ab0d97)
• Default value : [ OVTK_StimulationId_Label_00 ]

5. Result class label base

This stimulation is used as a basis for the stimulations to send when a state is selected. First state being selected would send exactly this stimulation. Second state would send this stimulation + 1 etc.

• Type identifier : Stimulation (0x2c132d6e, 0x44ab0d97)
• Default value : [ OVTK_StimulationId_Label_01 ]

6. Choose one if ex-aequo

This setting can force the box to choose a state even if more than one state have the highest score. In such case, there won't be any rejection. The way the box decides between the ex-aequo candidates is undefined.

• Type identifier : Boolean (0x2cdb2f0b, 0x12f231ea)
• Default value : [ false ]

Examples

This box is used in the P300 speller and the P300 magic card BCIs. Please see those scenarios in the sample openvibe-scenarios.

Miscellaneous