EEG-based Quantitative Analysis of Aesthetic Emotion in Clothing Design

Abstract This paper combines the perceptual aesthetic sentiments with the objective physiological responses of the human brain. By analysing the characteristics of the brain electrical activities in processing of different types of sentiments, this paper uses the specific physiological indicators of the brain to quantify the aesthetic sentiments about clothing. The purpose is to introduce the EEG quantitative analysis method for sentiment perception into the aesthetic field of clothing, and establish a theory of quantifying aesthetic sentiments towards clothing design through the brain electrical physiological responses.


Introduction
Sentiment is a complex process integrating multiple components, dimensions, categories and levels. Each occurrence of sentiment is related to physical and psychological factors, instincts and habits, and natural and social factors [1] . From various sentiment theories, it can be seen that sentiment is a mental emotion or feeling that is different from cognition or will.
It occurs in a specific situation and is a physical state related to changes in various parts of the body, accompanied by obvious or subtle behaviours.
The aesthetic sentiment of clothing can be summarized as the feeling that a person obtains through visual or tactile sensation in the aesthetic process of the clothing. It is the attitude and experience of the person towards the aesthetic object [2] . Such attitude and experience can lead to positive or negative feelings. Therefore, the generation of clothing sentiment is closely connected with the corresponding aesthetic process.
The traditional way of studying sentiment is usually to describe different sentiment dimensions by designing a semantic scale, which uses degree quantifiers, such as fairly, very, moderately and rarely, to evaluate the degree of sentiment [3] . This method can well track the emotions and feelings of people, but it is relatively subjective. Now that the modern design concept focuses on more objective evidence, it is necessary to convert sentiment, which involves the complex mechanism of psychological processes, into an objective theory and applied technology. For example, Taiwanese scholars use the female vest as an example to use adjectives to evaluate the mood of colour, and get a popular vest colour with fresh, Easy and soft features; or through the "wear acceptance", "wearing concern" and other aspects to develop clothing interest scales, and obtain support for letter and validity; or use degree quantifiers, such as: very, Very, general, and rarely, etc. to assess the degree of change in mood. These methods can better track people's emotional feelings, but they are relatively subjective. Under the premise that modern design concepts pay more and more attention to objective evidence, it is necessary to convert emotions, which are complex mechanisms involving psychological processes, into an objective theory and applied technology, and transform emotional sensory quantities into physiological changes.
It is known that people can respond physiologically when they feel various external stimuli and carry out a series of psychological activities. This reaction can be measured by it is processing different types of sentiments, we can quantify the sentiments using specific physiological indicators of the brain [4,5] , and explains the aesthetic sentiments towards clothing from a rational perspective.

EEG-BASED QUANTITATIVE ANALYSIS OF AESTHETIC EMOTION IN CLOTHING DESIGN
In addition, with the development of science, people started to study the perceptual sentiments rationally by the quantitative analysis approach [6] . This concept was first proposed by the Japanese scholar Mituo Nagamachi, which is called Kansei engineering.
He thought that Kansei engineering is a translation technique that translates customers' feelings and intentions into design elements.
At present, Kansei engineering, design psychology and ergonomics have been widely used in product design, which emphasize emotional design. Therefore, quantifying the aesthetic sentiments with specific physiological indicators according to the brain's responses and changes in processing of different types of sentiments can help people better understand an individual's cognitive process. which provides theoretical basis for the market research on product characteristics [7,8] . Figure   2 shows the widely used product sentiment model, which explains how the product sentiment is produced from a cognitive perspective.

Relations between clothing style and sentiment experience
The word "style" came from the lettering carved on stencils by Romans with needle or pen. The initial meaning was related to the distinctive way of writing. Since then, its meaning has been generalized, not only in literature but also in various fields. Obviously, different styles of clothing will give people different sentiment experience, so the design of clothing will significantly affect people's sentiments [9,10] . Both

Functional division of the brain
The brain is the centre of can be divided into scalp EEG and cortical EEG [8] . Since the acquisition of cortical EEG data requires a craniotomy of the subject, scalp EEG is more widely applied in practical applications.
For the purpose of this paper, EEG refers to scalp EEG. Scalp EEG is the superimposed reflection of the spontaneous and rhythmic electrical activities of brain neurons on the scalp and is obtained by electrodes placed on the scalp. Usually, EEG signals are divided into five frequency bands: delta, theta, alpha, beta and gamma. Its frequency range and characteristics are shown in Table 1.  Then the experimental data are compared with pre-recorded data in the experiment to determine the subjects' sentiments.

Analysis of aesthetic sentiments towards clothing design with EEG signals
Emotional production is not independent. It is accompanied by changes in the peripheral nervous system, central nervous system, and endocrine system, external behaviour, and psychology. It is a kind of experience, physiology, and interaction that arises from the interaction of objective things with human needs. The  Mainly appear on both sides of the back of the brain. The state of the human brain is often referred to as the subconscious state.

Beta 15~30Hz
Awake state <30uV Symmetrically distributed and mainly concentrated in the frontal lobe of the brain Gamma 30~100Hz Short-term memory and multi-modality different clothing styles, and generated the map of the subjects' preferences for different styles, as shown in Figure 7.
The sentiment analysis results obtained from the EEG signals proved to be consistent with the results obtained from subjective questionnaires. Therefore, it is reasonable and effective to use EEG signals to quantify the aesthetic sentiments towards clothing design.

Conclusions
Because the aesthetic emotion of clothing can be expressed through visual channels or through other sensory channels, such as touch, pressure, temperature, muscle, etc., real-time EEG data can be collected through multi-channel induction during experimental design. In addition, emotions can be evaluated