Metamerism Art 2013

http://www.cg.info.hiroshima-cu.ac.jp/

Computer Graphics Laboratory, Hiroshima City University

Mixing paints for generating metamerism art under 2 lights and 3

object colors

Daisuke Miyazaki Kanami Takahashi

Masashi Baba Hirooki Aoki

Ryo Furukawa Masahito Aoyama

Shinsaku Hiura


CG Lab, Hiroshima City University

Metamer sets

Light 1

Light 2

Same

Different

R: 93G: 79B: 94

R: 93G: 79B: 93

R: 81G: 77B: 98

R: 99G: 82B: 101

Introduction(1/3) Perception(3) Reflection model(5) Cost function(4) Experiment(3)



Related work

Art [Valluzzi 2012] Watermark [Bala, Braun, Loce 2009]

[Our work]Intentionally cause expected metamerism for oil painting art


Microbiology [Kobayashi, Yamada, Hiraishi, Nakauchi 2012]



Light 1 Light 2

Mix paint 3

Mix paint 1

Mix paint 2

Purpose




Light ObjectSpectral responseCIE-XYZ value

Human perception

Introduction(3) Perception(1/3) Reflection model(5) Cost function(4) Experiment(3)

400nm

800nm



Spectral distribution: same color

Color matching func.(CIE-XYZ)

Light 1 Paint 1

Paint 2

X: 0.36Y: 0.50Z: 0.14

X: 0.36Y: 0.50Z: 0.14

Light 1Color matching func.(CIE-XYZ)




Spectral distribution: different color

Color matching func.(CIE-XYZ)

Light 2 Paint 1

Paint 2

X: 0.35Y: 0.48Z: 0.17

X: 0.38Y: 0.46Z: 0.16

Light 2Color matching func.(CIE-XYZ)




Reflection model of mixing paints

[Finlayson, Morovic 2005][Alsam, Finlayson 2007][Miyazaki, Nakamura, Baba, Furukawa, Aoyama, Hiura, Asada 2012]

pp NN dwdwdws 2211pN

p

w

Nww ddds 2121

Elegant relationship

pp

pN

p NN

w

Nww dwdwdwddds logloglogexp 221121

21

Previous model: linear model Our model: exponential model

Our model = linear model in logarithmic space

Introduction(3) Perception(3) Reflection model(1/5) Cost function(4) Experiment(3)

d: spectral reflectancew: mixing weight



Incident light Diffusely reflected light

d1 =10

Reflectance: Paint 1





d2 =10

Reflectance: Paint 2





Reflectance =110

7 3d1 d2

101

Reflectance: Paint 1 & 2




Light E

Mixing weight w

Database D

Perception P

Recognized color

PEDw




Dw1 D

w2Dw3

Paint 1 Paint 3 Paint 2

Cost function

Introduction(3) Perception(3) Reflection model(5) Cost function(1/4) Experiment(3)



Cost function



PE D1w1 PE D PE D1 1

w w3 2

PE D PE D PE Dw w w2 2 2

1 3 2



E1

E2

Cost function




PE D1w3

PE Dw

23

PE D1w1 PE D1

w2

PE D PE Dw w2 2

1

PE D1w3

PE Dw

23 2

min

min

max

max

Cost function



min PE D1w1 PE D PE D PE D1 1 1

w w w3 3 2

PE D PE D PE D PE Dw w w w2 2 2 2

1 3 3 2min

max

max

Cost function




arg minw1, w2, w3

PE D1w1 PE D PE D PE D

2 0.51 1 1

w w w3 3 2

20.5PE D PE D PE D PE Dw w w w

2 2 2 21 3 3 2

Cost function




Artificial sunlight

Hyper-spectral camera

Diffuse whitereflectance standard

Narrow-bandfilter

Oil paints

Experimental equipments

Introduction(3) Perception(3) Reflection model(5) Cost function(4) Experiment(1/3)



Synthesized paint 3

Synthesized paint 2

Synthesized paint 1

Result

Introduction(3) Perception(3) Reflection model(5) Cost function(4) Experiment(2/3)




Computer Graphics Laboratory, Hiroshima City University

(c) Daisuke Miyazaki 2013All rights reserved.

http://www.cg.info.hiroshima-cu.ac.jp/~miyazaki/Daisuke Miyazaki, Kanami Takahashi, Masashi Baba, Hirooki

Aoki, Ryo Furukawa, Masahito Aoyama, Shinsaku Hiura, “Mixing paints for generating metamerism art under 2 lights

and 3 object colors,” CPCV, 2013.

Metamerism Art 2013

Technology

hiroshima city university

dw3experiment3cg lab

dexperiment3cg lab

mix paint

synthesized paint

dw1 paint

paint 2e2pe

cost function4cg lab