چكيده به لاتين
Visual information such as orientation, colour, and shape of the objects were analyzed separately in the primary visual cortex of the mammalian brain. The purpose of this project has been to classify the EEG signals taken through while viewing simple images into four different orientation stimuli (horizontal, vertical, and ± 45 degrees). Experimet tests of viewing images was designed and performed by nineteen subjects which after the secondary studies on gathered data, only the data of the four subjects were selected as database. After the removal of the eyelid movement and muscle effects, signals were entered into the feature extraction and classification step. The comparison of ERP signals for each subject in each of the four orientation showed that after viewing the images, a stimulation was observed in the corresponding EEG signals, which were placed on the four orientation with a slight difference in the attitude of the signals. These results indicated attention in subjects. After the appearance of the attention peak, EEG signals in each orientation had distinguished pattern at each time interval which was used for further classification of orientations. The results of the feature extraction indicated that for the specified time intervals, the integral of the data for each stimulus can determine the type of stimulus (angle). Four stimuli were used in this research form six categories (as two in a group). The integral feature of the comparator in each category could determine the type of signal based on the type of stimulus. The category classification accuracies of 100, 84, 94.7, 100, 100 and 68.4 percent were obtained for 1 to 6 categories respectively. In the next step, a number of statistical quantities was investigated at each of these time intervals and categories, among which were the maximum and average quantities for the fifth category and the standard deviations and variances for the third category, the root mean square for the first group and the second is the skewness quantity for the sixth category.
