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Sensory (Kansei) Engineering of Aesthetics in Textile FabricsCode Number: F99-S02 (formerly I98-S8)

PI(s): R.L. Barker, leader, M.W. Suh, M. McCord, J.L. Woo, I. Shalev, H.B. Kim -NC State

ANNUAL REPORT FOR : October 1, 1999

Goal Statement

We are applying principles of sensor (Kansei) engineering to design consumer pleasing textilematerials.

Abstract

Kansei Engineering seeks to correlate sensory perceptions, brainwave patterns and stimulusdimensions in order to optimize physiological and psychological environments and ultimately,tailor products directly to the preference of the consumer.

An important outcome of Kansei research is the discovery that stimuli that obey a 1/f relationshipon a log/log plot of power spectral density versus stimulus frequency (f) engender well-being andharmony, while brain alpha wave fluctuations of a comfortable/content individual are also foundto obey the 1/f relationship. In other words- though the exact interaction is yet undetermined- thehuman body prefers 1/f pattern sensory inputs and correspondingly outputs 1/f type signals inresponse to such inputs.

Translation of the “1/f” concept into textile fabric production specifications will essentiallycreate a new, all encompassing design guideline for all textile products, allowing themanufacturer to continually match consumer preference and compete with “non 1/f” designedfabrics. Our interdisciplinary team, in collaboration with Japanese researchers and industrialscientists, is well positioned to go beyond what has been done to date in Japan and to build theextensive theoretical and empirical groundwork required to formulate universal Kansei designrules for fabrics. Kansei engineering, by providing a window into the heart and mind of theconsumer, may be the key to designing and producing a new class of textile fabrics and products.In a consumer driven market, systematically engendering user preference at a fundamentalsensorial level can be the categorical competitive edge.

Background

Sensory (Kansei) engineering of aesthetics into consumer products has received considerableattention in Japanese national R&D projects including the Human Sensory MeasurementApplication Technology (HSMAT) project and the Ministry of International Trade and Industry(MITI) Technology Frontier Program. Nara, Tsukuba, Hiroshima and Shinshu universities allhave Kansei related programs. Kansei engineering seeks to “improve human well-being byoptimizing physiological and psychological environments. It is a tool to design products with an

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eye on observable physiological responses to stimuli. The goal is to tailor products to thepreference of every consumer (Nakano). Kansei can be simply defined as "sensory tailoring"(Nagamachi).

There is evidence that 1/f relationships hold true for visual, auditory, tactile, olfactory and tastestimuli. The 1/f relationships have been reported to exist in the song of a nightingale, themurmur of a stream, a Mozart serenade, a beautiful painting, the heart beat and in voltagevariations in nerve fibers. This discovery is especially meaningful because the 1/f pattern isfound to exist both on the stimulus side and on the physiological response side. Advances havebeen made in the methods of extracting 1/f patterns from optical and mechanical stimuli and inmeasuring 1/f brain alpha wave fluctuations in response to pleasing stimuli. There is a strongcase for investigating the applicability of 1/f as the most promising “Universal Kansei Tool”which can be utilized for designing 1/f stimuli engendering products on the one hand and forinterpreting physiological response to monitor favorable reaction on the other hand.

Research Objectives

To establish a scientific basis for applying the "1/f" concept – a revolutionary, mathematicallydefinable framework for determining and quantifying sensory preference, developed as part ofthe Japanese “Kansei Engineering” effort - for designing universally sensorially pleasing textilefabrics.

To design optical and tactile/mechanical measuring systems and software tools for convertingtextile fabric designs, textures and color combinations into electronic waveforms which can betransformed to reveal 1/f patterns and other frequency domain analyses.

To design a physiological measurement system, based on known scalp electro-potentialsmethods, for quantifying human sensation and perception generated by pleasing visual and tactilestimuli from textile fabric designs, patterns, textures and color combinations.

Progress

Our goal, for the seed project, has been to access, or develop, measurement technologies for thepurpose of demonstrating the potential utility of Kansei approaches for application in designingtextile aesthetics. We have made tangible progress in the following areas:

Measurement SystemsProgress has been made toward the development of a measurement system capable of

measuring optical patterns from planar surfaces. A statistically based computer program hasbeen developed for identifying 1/f patterns in optical patterns from planar surfaces. Theapplication of these procedures to convert optical patterns identifying 1/f relationships is shownbelow.

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Figure 1. NCSU Developed Conversion of Optical Patterns from 2-dimensional Imagesto Show 1/f Pattern

We observe that the more visually pleasing pattern (above left) produces a 1/f relationship on aspectral density plot, whereas the visually less pleasing pattern (above right) does not.

Biomedical StudiesPreliminary studies are underway in collaboration with researchers in the UNC

Department of Biomedical Engineering and Physiology, as well as the UNC School of Dentistry.The primary goal of this research is to determine the correlation between a measurablequantitative neurophysiological response to a sensory stimulus (e.g. fabric stroked across skin)and the subjective or emotional characterization of the sensory experience (i.e., pleasant vs.unpleasant). A set of fabrics with different levels of surface texture has been assembled for usein both human psychophysical experiments and in animal studies. Human subjective responsesto touching a particular fabric will be correlated with measured brain activity in animals evokedby touching the same fabric. Since the response of the somatosensory cortex to each fabric will

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be studied using the exact same stimulus for both the psychophysical and physiological testmethods, direct comparison of the perceptual and neural data will be possible.

Brain Wave MeasurementA working relationship has been established with Professor Toshimitsu Musha, president

of the Brain Function Laboratory in Kawasaki, Japan. Musha's laboratory features a system forbrain wave analysis called ESAM (Emotion Spectrum Analysis Method). ESAM permitsanalysis of brain function electroencephalogram (EEG) as a basis for quantifying human responseto external stimuli. ESAM analyses output from scalp electrodes show human emotionalresponses. We have begun a collaboration with Musha to determine the utility of ESAM as atool for gauging human response to the visual and tactile stimuli produced by textile fabrics(Professor Suh visited Musha's laboratory in Japan to view the ESAM system and to discussdetails of the collaboration). We are now working with Musha on two fronts: as a preliminarytest of ESAM's textile applicability, we have given Musha ten fabrics selected to represent a widerange of textile textures and hand (We have also characterized the physical properties of thesefabrics on the Kawabata Evaluation System). Musha is using the ESAM to characterize humanbrain wave response to the touch of these materials. We are discussing a lease arrangement withMusha that will enable installation of the ESAM system at NCSU by Fall 1999. Thisdevelopment will allow us to further explore the usefulness of ESAM as a means ofcharacterizing human response to textile aesthetics.

Future Work

This seed project will provide a foundation for future research that seeks to accomplish thefollowing goals, in its first year:

1. Establish laboratory techniques for quantitative characterization of physiological response tostimuli based on scalp electro-potential ("brain wave") measurement at key locations. Installbrain wave measuring procedures successfully demonstrated in Japan by Musha. Techniqueswill be adapted and enhanced using US cutting edge competency in bio-physiologicalscience, signal/ information processing and computer software.

2. Develop measurement systems for acquiring visual and tactile information from fabric andfabric-like surfaces. Install CCD system capable of measuring optical patterns from planarsurfaces with minimal loss of information.

3. Develop analytical and statistical procedures for identifying 1/f patterns in complex opticaland mechanical fluctuations. Employ techniques of statistical signal analysis to analyze andinterpret frequency spectrograms.

4. Provide qualification for the utilization of 1/f patterns as criteria for pleasing response tovisual and tactile stimuli from textile designs and materials.