Signal and Data Processing

fa سنجش عملکرد سامانه‌های رابط مغز و رایانه P300 Speller به‌ازای ماتریس نمایش ردیف و یا ستون (RCP) و نمایش حروف زبان فارسی Performance Analysis of a Persian text input brain–computer interface (BCI) P300 Speller system with row/column paradigm (RCP) مقالات گروه علائم حیاتی ( مرتبط با مهندسی پزشکی) Paper پژوهشي Research سامانه‌های رابط مغز و رایانه P300 Speller به‌عنوان عضوی از خانواده سامانه‌های رابط مغز و رایانه سعی دارد تا توانایی تایپ حروف و برقراری ارتباط با این شیوه را برای بیماران و معلولان فراهم آورد. یکی از موارد بسیار مهم در این سامانه‌ها، قابلیت شخصی‌سازی است. با توجه به آنکه بیش‌تر پژوهش‌های این حوزه بر اساس نمایش حروف انگلیسی انجام شده، در این پژوهش سعی شده است تا برای نخستین‌بار عملکرد یک سامانه ارتباط مغز و رایانه P300 Speller به‌ازای نمایش حروف زبان فارسی مورد سنجش قرار گیرد. در این پژوهش پس از ثبت داده از داوطلبان و سنجش عملکرد سامانه مورد بررسی، صحت تشخیص 21/88% و نرخ انتقال اطلاعات 74/6 بیت در دقیقه به‌ازای پانزده تکرار با  ترکیب روش کاهش بعد LDA و طبقه بند بیز به‌دست آمد. همچنین در این پژوهش اثر تغییر تعداد تکرار و کاهش زمان آزمایش نیز مورد بررسی قرار گرفت و نشان داده شد که به‌ازای کمینه تعداد تکرار، می‌توان به صحت تشخیص 06/80% و نرخ انتقال اطلاعات 43/42 بیت بر دقیقه دست یافت.   As a Brain computer interface system, BCI P300 Speller tries to help disabled people and patients to regain some of their lost ability with allowing communication via typing. The ability of personalization is one of the most important features in a BCI system, so the typing language as a personalization factor is an important feature in a BCI speller. Most prior researches on P300 Speller has focused on displaying English alphabet and there were only few studies made on other languages such as Chinese. In this research, we present a P300 Speller system, based on RCP, for Persian (Farsi) character input. RCP (Row or Column Paradigm) was introduced by Farwell and Donchin at 1988, and since then it has been considered as a benchmark in P300 BCI speller research. As a result, in this study also, Row or column paradigm was selected as the base stimulation pattern in P300 speller system. In order to evaluate the Persian row or column paradigm performance, we recorded EEG signals from volunteered subjects while the stimulation pattern was being displayed. It should be noted that the test was explained to each subject before testing, and for more experience and in order to reduce the error, each subject participated in an experiment test before attending the main test. These EEG signals were recorded from 8 channels based on ‘‘Fz’’, ‘‘Cz’’, ‘‘P3’’, ‘‘Pz’’, ‘‘P4’’, ‘‘O1’’, ‘‘Oz’’ and ‘‘O2’’ site in accordance to the International 10–20 system electrode placement system and by using Science Beam co.’s EEG recording device. The sample rate was 1 KHz which was down sampled to 250Hz. After recording, the EEG signals were filtered using a band passed filter And for classification, Linear discriminate analysis was used in combination with K-fold validation method for classifier training. As performance determination, we calculated accuracy and bit rate for the mentioned system based on recorded data from volunteers and reached the average accuracy of 88.21% and bit rate of 6.74 (bits/minute) (we use Linear LDA classifier for classification and the total trial number was set to 15). Furthermore, in this research performance was measured for different trial number and final results demonstrated that this system can achieve high average accuracy of 80.06% and average bit rate of 42.43 (bits/minute) by using only 2 repetitions.   سامانه‌های رابط مغز و رایانه, سامانه P300 Speller BCI, روش کاهش بعد LDA, مؤلفه P300 , طبقه‌بند بیز Brian computer interface systems, BCI P300 Speller, P300 wave, LDA classifier 131 140 http://jsdp.rcisp.ac.ir/browse.php?a_code=A-10-750-1&slc_lang=fa&sid=1 Mohammad Mikaeili محمد میکائیلی Mikaeili@shahed.ac.ir 10031947532846005483 10031947532846005483 Yes Shahed University دانشگاه شاهد foroogh Najafi فروغ نجفی foroogh.najafi.c@gmail.com 10031947532846005484 10031947532846005484 No Shahed University دانشگاه شاهد