bci2000.org BBS

Hi In fact , I am not exactly get your question ,But I guess the following example will help you ! For first question , let's assume that there are 10 word to type by BCI2000 . So there are 10*180 intensifications . It means each row/col intensify 15 times for one word (180 = 15*12 ; 12(row&col)...

Hello , I don't know will you read this post but I hope will. In fact, I have a problem to ask you. That is what kind of SVM parameters you set ? I am using libsvm .There are some parameters to set , such as -s -t -c -g and so on. The feature extracted from P300 signal input SWLDA got adaptive perfo...

Hi everyone, I have a problem about SVM in P300 Classification. I want to know what kind of kernel function mostly used in this field ? I have used SWLDA to classify P300 data which can gain adoptive result . While with the same feature vector , SVM get very poor performance . I use libsvm ,paramete...

I am sorry for too late to see it . If your mean the feature extraction in BCI2000 ,that is average the data between each stimulus start time and later 800ms according to each row/column ,in the selected channels. Then concatenate them in a vector ,i.e. feature vector . For example , if the number o...

Hi , everyone. I have read the article about feature extraction . "BCI Competition 2003—Data Sets Ib and IIb-Feature Extraction from ERP with the CWT and t-Value Scalogram" . And I want to realize the method provided in this article . But I have some problems . 1. In fact , I have met in m...

Hi, everyone . Is there anyone know t-CWT ,a kind of method for feature extraction from ERPs. Recently ,I am learning about it , but I met some problems. 1. How to do the data preprocessing for t-CWT ? 2. If there is 180 trials (fifteen 12-trial blocks), that is, 30 trials belong to target group ,15...

I have solve this problem. Because matlab load the .dat file according the file path ,but the "load_bcidat.m " will can't find when the workpath re-set to the data path . By means of the following method will work. filename = strcat(pathname,filename); [signal, states, parameters] = load_b...

Hi every! I have a question that is the "load_bcidat" can only load the .dat file which is in the same storage position with the "load_bcidat.m" and "load_bcidat.mexw32" ? I want to load some .dat files which are in another folder by means of "load_bcidat.m" i...

Thanks, sincerely !

Sandra.

I have solved this problem ,if anyone met the same problem ,you can read this.

I have solved this problem ,if anyone met the same problem ,you can readthis .

Yes , I use the function load_bcidat . 1. [signal, states, parameters] = load_bcidat(filename, '-calibrated'); I tested this code with my matlab code ,and I can get same result when apply to my data acquired from NeuroScan .In fact the data which is loaded by '-calibrated' code is equal to the outpu...

Thanks for your help ,Chad ! In fact , I did the work what your suggestion a few days ago, I set the gains to 1 and offsets to 0, AlignChannels = 0;TransmitChList = 10 (the channel number) , the classifier is :1 1 1 1 (that is, just use one element of the TransmitChList channel as feature). The resu...

Hi Chad! Thanks for your reply! I had little confuse about how the dat file written . Now I understand what your reply about "the data are simultaneously written to a dat file and passed through the BCI2000 filter pipe" . 1.I have read the DataIOFilter's source code ,the SourceChOffset and...

Hi,everyone! I have some questions about the .dat file of P300Speller. 1.After the BCI2000 run,when the .dat file began to write? 2.Was the .dat file have pass through the DataIOFilter? If is not , where and when did the SourceChOffset and SourceChGain used ? 3.If I want to analog the SpatialFilter ...