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TitlesThree-dimensional computer graphic simulation to develop base makeup for
pearly skin
Kumiko, Nishiyama1; Kensuke, Tobitani2; Atsushi, Ishida2; Lisa, Park2; Noriko, Nagata2;
Akihiro, Okada1
1

Naris Cosmetics Co., Ltd., 11-17, 1-chome Ebie, Fukushima-ku, Osaka 553-0001, Japan2

Kwansei Gakuin University, 2-1, Gakuen, Sanda, Hyogo 669-1337, Japan

Keywords: Base makeup, Pearly skin, 3DCG simulation, Blurring[Short summary]
Pearls have attracted attention because of their elegant beauty. In this study, we propose applying
the luster of pearls to cosmetic products. We conducted research on the influence of the opticalphenomena of pearls embodied on a human face using a three-dimensional computer graphic (3DCG)
simulation. The unique luster of pearls is the result of a complex optical phenomena caused by theirmultilayer structure. Nagata et al. suggested new optical models for the optical phenomena of pearls
and succeeded in generating high-quality 3DCG images of pearls. We applied these optical models toa 3DCG model of the human face and generated images of a human face with the luster of pearls.
Figure 1 shows the conceptual diagram of creating pearly skin. We also conducted a subjective
evaluation of these images and examined the association between the optical phenomena of a pearl
and the evaluation factors of a face. We found that the influence of blurring on the evaluation factors
was the most effective among the optical phenomena of pearls when applied to a human face. The
results indicate that the influence of blurring is a valuable indicator for the development of base makeupthat has a pearly appearance.

Figure 1: Conceptual diagram of creating pearly skin.

[Introduction]
Pearls, which are widely used in jewelry, have attracted attention since ancient times because of
their elegant beauty. The charm of pearls, i.e., their smooth luster and deep gloss, is ideal for the skin ofa woman. In this study, we propose applying the luster of pearls to cosmetic products. First, we
conducted research on the influence of the optical phenomena of pearls embodied on a human face
using a three-dimensional computer graphic (3DCG) simulation. Visual simulations using computer
graphics have attracted considerable attention as a method of analysis by synthesis. The time and costof conducting trials and evaluations can be significantly reduced using a 3DCG simulation. Pearls have331

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Titlesa multilayer thin-film structure and display a unique rainbow color pattern and lustrous iridescenceowing to the diverse behaviors of light, such as refraction, interference, diffraction, and multiple
reflections. Nagata et al. succeeded in achieving a realistic representation of a pearl by means of threeprincipal factors, the interference, mirroring, and texture components, using physics-based modeling [1].
Dobashi et al. indicated that the blurring of light was an important fourth factor in improving therepresentation of a delicate appearance, and proposed a computational model and calculation
algorithm [2]. Furthermore, a new model, the “partial coherent model,” which considers both coherent
light and incoherent light used in the visualization of the interference phenomenon in [1] has beenproposed. These studies successfully generated high-quality perfect sphere pearl CG images [1][2].
The authors of this paper applied the pearl visualization method to a free-form surface [3]. Using themethod presented in [3], we represent the luster of pearls on a human face and generate CG images ofa human face with the luster of pearls. We also conduct a subjective evaluation of these images andexamine the association between the optical phenomena of a pearl and the evaluation factors of a face.
The association has potential application in the field of cosmetic preproduction to help develop basemakeup for pearly skin.
[Methodology]
Generating a Pearly Skin Face Image
In this study, we selected interference and blurring as suitable factors to represent the features ofpearls on a human face.
The interference phenomenon observed in a pearl is the mixture of the interference of coherent light(dependent of the direction of the light source) and incoherent light (independent on the direction of thelight source). The interference of coherent light is general thin-film interference. On the other hand, theinterference of incoherent light is the phenomenon specific to pearls. The incident light is distributed tothe whole pearl layer through repeated reflection and refraction. As a result, it appears as if each pointin the layer has a point light source transmitting rays in all directions. Each ray causes local interference,and interference lights are propagated in all directions outside the pearl. This accounts for the fact thatthe hue of the interference light does not depend on the direction of the light source.
Blurring is the spread of light owing to the deviation of light from the direction of the regular reflection.
The quite high transmittance of the nacreous layer causes light to be repeatedly reflected andtransmitted inside the layer. As a result, the spread of light inside the layer tends to have the propertiesof reflection and transmission rather than scattering.
We simulated these optical phenomena of pearls, i.e., interference and blurring, as performed inprevious studies [1][2][3].
We used the Bio Skin Doll as a model for the facial form and applied the optical phenomena ofpearls to the doll. For the generation of 3DCG images, MAYA, a 3DCG software application, was used
to represent the shape, texture, and optical properties of the doll.
We measured specular reflectivity of the Bio Skin Doll using a goniophotometer. In addition, we
measured the color of the doll using a spectrophotometer. The texture component was extracted from a332

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Bio Skin Doll

photograph of the doll and wasMeasurement

applied to bump mapping. Figure 2
shows the procedure employed tosynthesize a 3DCG image of a face

Goniophotometric
ReflectanceSpectralReflectance

Texture
Image

Pearl

3D
Shape

Simulation

with pearly luster.
Light Source
Information

EvaluationofPearly

Skin

FaceSkin

Doll

Shader(MAYA)

Incoherent LightInterference

Coherent LightInterference

Image GenerationImages
WeBlurring

Doll Image

generated

BioShader(MAYA)

images using the methods described

Image Generation

above with different levels of blurring,

Pearly Skin Face Image

interference of coherent light, andinterference of incoherent light. We

Figure 2: The procedure for synthesizing a 3DCG image for aface with pearly luster.

evaluated these images by surveying
215 women. We then analyzed how each optical phenomenon influences the evaluation factors. In
particular, we defined as dependent variables the factors that affect base makeup finishing, such as
coverage effects, smoothness, finishing, concealment of pores, luster, skin color preference, oily glare,and translucency. Here we utilized the parameters of the optical phenomena of pearls as explanatory
variables to perform a multiple linear regression analysis.
[Results]
We applied the simulated optical phenomena of pearls to thedoll and succeeded in generating 3DCG images of a face with apearly luster, as shown in Figure 3. We subsequently evaluated
the generated images with different levels of optical phenomenaof pearls, as shown in Figure 4 (A–G). Some of the images wererated high. For example, images A and B received the highestratings. Table 1 shows the blurring, interference of coherent light,(a) Bio Skin Doll(b) Bio Skin Dollwith pearly luster

Figure3 : Generated Bio Skin Doll images.

and interference of incoherent light values, and the ratings received for each Bio Skin Doll image.
Figure 5 shows the rating values of the evaluation factors of a face. Each image received different
ratings from an evaluation of base makeup finishing.
Table 1: Parameters and Received Rating Values ofEach Bio Skin Doll Image

Figure 4: Generated Bio Skin Doll images with different
levels of blurring, interference of coherent light, andinterference of incoherent light.

333

ImageBlurring

A
B
C
DEF
G22324

Interference of Interference ofRating ValueCoherent Light Incoherent Light
3.50.002
3.5
0.003
2.80.003
3.3
100.0022.9
100.002
3.4
100.002
3.2

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Table 2 shows the standardized partial regression coefficients obtained by the multiple linear
regression analysis. We found the influence of blurring to be the most effective in terms of evaluation
factors. Thus, greater the level of blurriness, higher are the ratings for the other factors, such as
finishing, luster, skin color preference, oily glare, and translucency. Therefore, it can be concluded that
influence of blurring on the evaluation factors was the most effective among the optical phenomena ofpearls when applied to a human face.
5.0

Table 2: Standardized Partial Regression Coefficients
Obtained by Multiple Linear Regression Analysis
explanatory
variables
dependent
variables

3.0

2.0ABCDEFG

blurring

incoherent lightinterference

coherent lightinterference

coverage effects

ns

ns

ns

smoothness

ns

ns

ns

0.193*

ns-0.169*

ns

ns

ns

luster

0.336***

ns

ns

skin color preference

0.162*-0.137*-0.165*oily glare

0.319***

ns

ns

translucency

0.152*

ns

finishingtranslucency

oily glareskin color preference

lusterconcealment of pores

finishingsmoothness

1.0

coverage effects

Rating value

4.0

concealment of pores*p<0.05. ***p<0.001.

nsns : not significant

Figure 5: Rating values for each Bio Skin Doll image.

[Conclusion]
We succeeded in generating facial images with a pearly luster by simulating the optical phenomenaof pearls and applying the results of the simulation to the Bio Skin Doll. We then generated Bio Skin
Doll images using different levels of interference and blurring, and subsequently evaluated theseimages, some of which received high ratings. We analyzed the association between the parameters of
the optical phenomena of pearls and the evaluation factors, and determined that influence of blurringon the evaluation factors was the most effective among the optical phenomena of pearls. The results
lead to the conclusion that the influence of blurring is a valuable indicator when developing basemakeup for pearly skin. In future, we will develop base makeup products that make use of the blurringof pearls and conduct evaluations of these products.
[References]
1) N. Nagata, T. Dobashi, Y. Manabe, T. Usami, and S. Inokuchi, “Modeling and visualization for apearl-quality evaluation simulator,” IEEE Trans.Visual. Comput. Graphics, vol. 3, pp. 307-315,
Oct./Dec. 1997.
2) T. Dobashi, N. Nagata, Y. Manabe, and S. Inokuchi, “Implementation of a Pearl Visual Simulator
Based on Blurring and Interference,” IEEE/ASME Transactions on Mechatronics, vol. 3, no. 2, pp.
106-112, June. 1998.
3) K. Tobitani, A. Okada, K. Nishiyama, A. Ishida, L. Park, and N. Nagata, “A Simulation of Multilayer
thThin-film Interference for Pearl Material Preproduction,” 19
Frontiers of Computer Vision, pp. 107-112, Jan./Feb. 2013.

334

Korea-Japan Joint Workshop on