Determination of the 25th Frame with the Eeg Signals Stored in the Videos

NESciences, 2019, 4(2): 92-106 -RESEARCH ARTICLEDetermination of the 25th Frame with the Eeg Signals Stored in the Videos Gözde Özkan1*, Ahmet Gökçen2 1 The Graduate School of Engineering and Science, Iskenderun Technical University, Turkey 2 Department of Computer Engineering, Iskenderun Technical University, Turkey Abstract Nowadays, the videos that appear in every part of our lives are a set of images resulting from the sequential addition of a series of image files. One second of the video is the result of the merging of 24 picture frames. The visual subliminal perceives 24 frames per second. It is difficult to see hidden pictures in the frames of videos which is called the 25th frame effect. In this study, electroencephalogram (EEG) signals are analyzed and it is aimed to determine whether or not the 25th frame effect is perceived by the brain. For this purpose, 6 different videos were shown to 50 participants. The participants watched videos which are contain a raw and 25th frame effect. And EEG signals were recorded by Emotive Epoc+. Statistical feature extraction algorithms were applied to EEG signals. K-nearest neighbor (KNN) classifier and Naive Bayes(NB) classifier, were used for classificstion. Training was performed by applying the k-fold cross validation. The KNN classifier's performance are as follows; overall accuracy of 96.60%, recall of 98.00%, F1 score of 96.50%, precision of 95.29%. The NB classifier's performance are as follows; overall accuracy of 92.00%, recall of 92.00%, F1 score of 92.20%, precision of 92.00%. Keywords: Electroencephalography Signals, Brain Computer Interface, 25th frame, Subliminal Messages. Article history: Received 20 April 2019, Accepted 05 May 2019, Available online 16 May 2019 Introduction A video is called a series of images resulting from the sequential addition of a series of images. The number of images displayed in 1 second of a video is called frame per second (fps) (Davis et al., 2015 ; Özcan et al., 2015). A one-second video has been composed by 24 frames. However, if the video has the 25th frame, the viewer could create it at the level of consciousness and works in * Corresponding Author: Gözde Özkan, e-mail: Natural and Engineering Sciences 93 his subconscious. In the literature, this situation, which is called the 25th frame effect, is usually used by advertising companies to influence the viewer through subliminal message delivery (Vokey, 2013; Karremans et al., 2006; Küçükbezirci, 2013). The Radio and Television Supreme Council (RTÜK), which provides control of television broadcasts in Turkey, stipulates that subliminal advertisements of this type should not be allowed. Consciousness is the moment of awareness in people. At the level of consciousness, perception is open and emotions are felt. The subconscious is another structure consisting of movements, thoughts and behaviors in the state of consciousness. Movements in the state of consciousness directly affect the subconscious (Florea, 2016). The aim of this study is to determine if the brain perceives the hidden pictures in the videos that are thought to affect people's subconscious. The signals were recorded using the Emotiv EPOC + device, which is mounted on a wireless hood and is connected to the computer via Wi-fi. Two of the 16 channels of the Emotiv EPOC + device are used as reference points. The Emotiv EPOC + device is non-invasively attached to the scalp, allowing electrode information from the brain. Electroencephalogram (EEG) recordings can be used for observing the changes of human emotions in brain signals (Altan et al., 2016). EEG signals are widely used in emotion estimation applications In the mid-90s, people began to teach emotion estimation to machines. Hans Berger was the first to associate EEG signals with sleep. The first EEG-based classification was made in 1937 by Loomis and his assistants (Williams et al., 1974 ). There are many studies in the literature about the effect of EEG signals on emotions. In the studies, emotion analysis and classification process were used for different types of stimuli using EEG signals and facial expressions (Murugappan et all., 2008 ; Soroush et al., 2018; Daşdemir et al., 2017 ; Atasoy et al., 2014). Emotions are reflected in body language, facial expressions, voice tones. For this purpose, the participants evaluated the audio-visual stimuli. Accordingly, EEG findings were classified according to their positive and negative conditions. (Soleymani et al., 2016 ; Liu et al., 2010 ; Özerdem & Polat, 2016). Emotions are expressed by music, tone, voice, facial expressions, gestures. Music videos are also used for observing the emotional effects. Participants have rated each video in terms of the levels of arousal, valence, like/dislike, dominance, and familiarity by The bodily reactions of the user have been translated into EEG signals (Koelstra et al., 2012). In another study, the participants were listened to unpleasant sounds and EEG recordings were recorded. As a result, it was observed that spontaneous mimic movements increased during the application of unpleasant sounds (Grunwald et al., 2014). In some studies, it has been examined how brain performance is affected by music, picture and meditation by analsing EEG from the patients wtih psychological trauma or chemotherapy treatment (Bhattacharya & Lee 2016 ; Tan et al., 2014; Fidan & Özkan 2018). In a study, classification was performed by EEG signals for the diagnosis of epileptic diseases (Acharya et al., 2011). With the development of emotion recognition studies, the neuromarketing sector has been emerged. With the transfer of the data obtained in neurological research to the marketing discipline, the field of neuro-marketing has emerged. Studies are integrated into this field. The effect of advertising, brand selection and product design on the brain was investigated. By analyzing at the EEG signals of consumers, it was investigated how they gave the purchase decision and which marketing tools were affected. Neuromarketing has focused on how advertising and marketing Natural and Engineering Sciences 94 stimulates nerve centers in the brain (Wang et al., 2018 ; Yücel & Coşkun 2018). As a matter of fact, EEG signals while watching the advertisements were recorded and emotional reactions were examined (Elden, 2009). As a result of analysis on EEG, studies were conducted to detect the likes of the brands that they have seen in television commercials (Custdio, 2011). Material and Methods The study was carried out in three stages as data acquisition, feature extraction and classification respectively. Figure 1 shows the working flow chart. Figure 1. Flow diagram of the study. Data Acquisition In this study, six different videos including animal, plant and nature themes were prepared. These videos are divided into frames. Pictures are added to be randomly positioned between the frames. Frames are reassembled to form a new video with hidden (...truncated)