bci4eval

 BCI4eval evaluates a BCI-result for two and more classes

   Two classes are evaluated like in [1,2]:
   - It returns the classification error, the signal to noise ratio, 
   the mutual information, as well as mean, standard error, 
   within-class accuracy and standard deviation for both classes. 
   - time course of these resulting parameters are supported

   More than two classes are evaluated with 
   - Kappa coefficient including standard deviation 
   - Accuracy
   
   Missing values can be encoded as NaN.

 X = bci4eval(tsd,trig,cl,pre,post,Fs)
 INPUT:
       tsd     continous output 
               for 2 classes, tsd must have size Nx1 
               size NxM for M-classes, for each row the largest value 
               determines the assigned class 
       trig    trigger time points
       cl      classlabels
       pre     offset of trial start 
       post    offset of trial end 
       Fs      sampling rate;

 OUTPUT: 
       X is a struct with various results  
       2-classes:
               X.MEAN1, XMEAN2: mean of both classes      
               X.ERR           error rate 
               X.p_value       significance level of paired t-test 
               X.SNR           signal-to-noise ratio
               X.I             mutual information
               X.AUC           area-under-the-(ROC) curve
       N(>2)-classes:
               X.KAP00         Cohen's kappa coefficient
               X.Ksd00         standard error of kappa coefficient 
               X.ACC00         accuracy 

               X.MEAN0         average output of non-active class                
               X.MEAN1         average output of active class
               X.SNR           signal-to-noise ratio for each class
               X.I             mutual information for each class
               X.AUC           area-under-the-(ROC) curve for each class
               X.r             correlation coefficient (parametric) 
               X.rankcorrelation    rank correlation (non-parametric)
               X.I_Nykopp      Nykopp's mutual information
               X.I_Wolpaw      Wolpaws mutual information 


 see also: SUMSKIPNAN, PLOTA, BCI3EVAL

 REFERENCES:
  [1] Schl�l A., Neuper C. Pfurtscheller G.
    Estimating the mutual information of an EEG-based Brain-Computer-Interface
    Biomedizinische Technik 47(1-2): 3-8, 2002.
  [2] A. Schl�l, C. Keinrath, R. Scherer, G. Pfurtscheller,
    Information transfer of an EEG-based Bran-computer interface.
    Proceedings of the 1st International IEEE EMBS Conference on Neural Engineering, pp.641-644, Mar 20-22, 2003.
  [3]  A. Schl�l, Evaluation of the dataset III of the BCI-competition 2003.
    http://ida.first.fraunhofer.de/projects/bci/competition/results/TR_BCI2003_III.pdf
 [4] Schl�l A, Kronegg J, Huggins JE, Mason SG;
    Evaluation criteria in BCI research.
    (Eds.) G. Dornhege, J.R. Millan, T. Hinterberger, D.J. McFarland, K.-R.M�ler;
    Towards Brain-Computer Interfacing, MIT Press, p327-342, 2007