a model for the d evelopment of analytical information ... · cultural heritage are objects of...
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Science and Technology for Art Conserving and Recording Tangible, Intangible, and Natural Heritage
Summer School 4-7 September 2012, Manila, Philippines
1
A model for the development of analytical information database: A case study on Japanese
pigments and dyes
1. Introduction
Cultural heritage are objects of precious nature possessing tangible and intangible attributes of
a group or society that has been passed down through generations. One important aspect related to the
study of these objects has something to do with its material properties. For example in the case of
Japanese cultural heritage, pigments and dyes are ubiquitous. In this paper, a database of analytical
information on hundreds of Japanese pigments and dyes is introduced. The characterization techniques
used are classified either as spectroscopy or imaging. These techniques are used to acquire different
kinds of material information such as spectral reflectance, color information, crystallinity, elemental
composition, and spatial information. In addition, the concept of analytical imaging is introduced. The
tools and techniques used are spectrometer, XRD, SR-XRF, SEM and high-resolution multispectral
imaging. The sample preparation method is described and selected results are discussed. These material
information are collected to deepen the understanding of the mechanism of color formation and material
degradation of pigments and dyes. This could help in the efforts geared towards preservation,
conservation and restoration of cultural heritage.
2. Spectral Reflectance and Colorimetric
a. Sample Preparation and Measurement
The spectral reflectance and color information of the pigments and dyes were measured using
spectrometers. The color information such as CIELAB, CIEXYZ and sRGB were measure using an
X-rite SP60 Portable Sphere Spectrophotometer. This device could measure opacity, color strength in
chromacity, apparent and tri-stimulus calculations, and 555 shades sorting for precise color control of
products involving plastic, painter or textile materials [1]. It could also do simultaneous measurements
of both specular-included (color) and specular-excluded (appearance) which could determine the
influence of the specular component. The samples used for measurement are pigments and dyes painted
on paper which were prepared in the traditional Japanese way. The samples were part of a pigment and
dye book prepared by a master Japanese painter.
On the other hand, the spectral reflectances were measure using a mini spectrometer C10083MD
made by Hamamatsu Photonics Co. The samples were measured in the range of 320 nm to 1000 nm at
45/0 geometry at 5nm and 10nm intervals. Halogen lamp was used as the light source and barium sulfate
was employed as the white standard. The spectral reflectance of the target r( ) is obtained through the
Science and Technology for Art Conserving and Recording Tangible, Intangible, and Natural Heritage
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following equation:
)()(
)()()(
dw
dtr
where is the wavelength, t( ) is the sensor response from the light reflected by the target, w( ) is
the sensor response from the light reflected by the white standard, and d( ) is the dark current of the
sensor.
b. Selected Results
Figure 1 shows a selection of Japanese pigments made into a color chart and Figure 2 shows the
corresponding spectral reflectance. This pigment chart has been used extensively as learning sample for
pigment estimation and spectral reflectance reconstruction of pigments and dyes on Japanese artworks
[2-30].
Figure 1: Patches of Japanese pigments and dyes which are part of the database
Science and Technology for Art Conserving and Recording Tangible, Intangible, and Natural Heritage
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Figure 2: Spectral reflectance corresponding to the pigments and dyes in Figure 1.
3. X-ray Diffraction
a. Sample Preparation and Measurement
X-ray diffraction is a very useful nondestructive method for studying crystal structure of
materials. It can be used to detect the phases present in samples and provide information on the physical
state of the sample, such as grain size, texture and crystal perfection [31]. X-ray diffraction peaks are
produced by constructive interference of monochromatic beam scattered from each set of lattice planes
at specific angles. The peak intensities are determined by the atomic decoration within the lattice planes.
Consequently, the X-ray diffraction pattern is the fingerprint of periodic atomic arrangements in a given
material. An on-line search of a standard database for X-ray powder diffraction pattern enables quick
phase identification for a large variety of crystalline samples [32]. The spacing in the crystal lattice can
be determined using Bragg’s law given by the equation below:
2 sinn d
Where n is the diffraction order, λ is the wavelength, d is the spacing between the planes in the atomic
lattice, and θ is the angle between the incident ray and the scattering planes.
The experiment for creating the XRD information database was conducted using X-ray
diffractometer (MultiFlex, Rigaku) at the Nanometrics Laboratory, Department of Micro Engineering,
Kyoto University. The pigment and dye samples used for the measurements come in two different forms.
The samples are measured either in powder form or painted on paper form. The painted samples were
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350 400 450 500 550 600 650 700 750 800 850
Wavelength [nm]
Refl
ecta
nce
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either taken from the pigment book prepared by traditional Japanese painting master or prepared in the
lab using traditional preparation method. 2 scanning was performed at 75152 with CuKα
line (wavelength: 0.154 nm) at 40 kV and 40 mA. The sampling width and the scanning speed were
0.02º and 3.00º/min respectively.
b. Selected Results
Figure 3 shows representative XRD results. Two pigments were chosen as representative sample
namely malachite (a) and azurite (b). These pigments are widely used in Japanese artworks to depict
green and blue hues. The XRD of malachite shows the influence of sample preparation. The selected
samples have the same grain size but prepared three different ways: B: from the pigment book; P:
prepared in the lab and painted on Japanese paper; and P’: in powder form from a Japanese pigment
supplier (ナカガワ胡粉絵具). On the other hand, the XRD of the selected azurite samples shows the
influence of powder grain size.
(a)
(b)
Figure 3: Representative XRD peaks of malachite (a) and azurite (a).
4. Synchrotron Radiation X-ray Fluorescence
a. Sample Preparation and Measurement
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Synchrotron radiation (SR) analyses were performed at beam line 4A of the Photon Factory in
Tsukuba, Japan. The electron beam energy in the storage ring was 2.5 GeV, with a maximum current of
400 mA. Incident X-ray energy was 15 keV. The cross-section of the beam was approximately 1(v) x
1(h) mm2 on the sample. The synchrotron radiation was monochromated by a multilayered reflecting
mirror. Precise beam size of monochromated X-rays was adjusted using slits. The incident and
transmitted X-rays were monitored by ionization chambers that were set in front of and behind the
sample. The fluorescent X-rays were collected by a solid-state detector at 90 degrees to the incident
beam. Measurements were performed in air. Point spectra were measured for obtaining consistent
elements of the samples. The spectra were obtained by using a multi-channel analyzer. The measurement
time was 100 seconds for each spectrum. The collected data were used to analyze SR-XRF spectra. The
pigment and dye samples were measure either in powder or painted form.
b. Selected Results
XRF spectra were measured to collect accurate information on the elemental composition of the
pigments and dyes in the database. Figure 4 shows the XRF spectra of representative Japanese pigments.
(a)Azurite (b) Malachite
(c) Cinnabar (d) Hematite
0 5 10 15
1
10
100
1000
10000
100000
Inte
nsity [a
.u.]
Energy [keV]
Cu KCu K
Cu esc
Pb L
0 5 10 15
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1000
10000
100000
Inte
nsity [a
.u.]
Energy [keV]
Cu KCu K
Cu esc
0 5 10 15
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100000
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nsity [a
.u.]
Energy [keV]
Hg L
Hg L
Hg L
Hg LHg L
0 5 10 15
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100
1000
10000
100000
Inte
nsity [a
.u.]
Energy [keV]
Cu KPb L
Fe K
Fe K
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(e) Ocher (f) Jade
(g) Vermilion (h) Lapis Lazuli
(i) Coral Powder (j) Minium
0 5 10 15
1
10
100
1000
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100000
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ten
sity [a
.u.]
Energy [keV]
Cu K
Pb LSi K
Fe K
Fe K
Ar K
Ca K
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1000
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100000
Inte
nsity [a
.u.]
Energy [keV]
Pb L
Si K
Fe KZn K
Ar K
K K
K K
Fe K
Pb L
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10
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1000
10000
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nsity [a
.u.]
Energy [keV]
VR
VK
VO
VY
Hg L
Hg L
Hg L
Hg L
Hg L
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1000
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100000
Inte
nsity [a
.u.]
Energy [keV]
Pb LSi K
Fe K
Zn K
Ar K
Ca K
Ca K Fe K
Cu K
S K
K K
Ti K
0 5 10 15
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10
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Inte
nsity [a
.u.]
Energy [keV]
D
E
Ca K(sum)
Zn K
Ca K
Pb L
Ca esc
Zn K
Fe K
Ca K
0 5 10 15
1
10
100
1000
10000
100000
Inte
nsity [a
.u.]
Energy [keV]
Pb L
Pb L
Pb L
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(k) Sodalite (l) Agate
Figure 4: XRF spectra of representative mineral pigments used in Japanese cultural heritage
5. Scanning Electron Microscopy
a. Sample Preparation and Measurement
SEM images were acquired on selected pigments to investigate influence of particle size and
distribution on the color formation of pigments. The pigments used for the characterization are in
powder form from a Japanese pigment supplier (ナカガワ胡粉絵具). JSM-6701F (JEOL) was
employed for SEM measurement. The acceleration voltage of the electron beam was 5 kV. The emission
-5 Pa. Every sample was
coated with Pt-PD using E-1030 Ion Sputter (Hitachi Co). The discharge current in sputtering was 13
mA, and the degree of vacuum in the chamber was 1.055 Torr. The sputtering time was 120 msec.
b. Selected Results
Figure 5 shows the SEM images of selected Japanese pigments found in the database.
0 5 10 15
1
10
100
1000
10000
100000
In
ten
sity [a
.u.]
Energy [keV]
Pb L
Si K
Fe KZn K
Ar K
Ca K
Ca K
Fe K Zn KMn K
0 5 10 15
1
10
100
1000
10000
100000
Inte
nsity [a
.u.]
Energy [keV]
Cu K
Pb L
Si K
Fe K
K K
Fe K
Ar K
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(a) Azurite (b) Jade
(c) Agate (d) Sodalite
(e) Cinnabar (f) Hematite
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(g) Ocher
Figure 5: SEM images of selected Japanese pigments found in the database
6. High-resolution multispectral analytical imaging
a. Multispectral analytical imaging (MAI)
Analytical imaging refers to the technique which uses image processing, data mining and pattern
recognition to extract useful and relevant information about different properties of a material. This is
based on the fact that a material subjected to an incident electromagnetic radiation behaves in a
predictable and quantifiable way. A simple radiation-matter interaction model is depicted by Figure 6.
The characteristic material response depends on the energy and frequency of the radiation. In this case,
the focus was given within the visible- near infrared range of the electromagnetic spectrum. The material
response is quantified based on its spectral properties, colorimetric information and spatial features. In
the proposed analytical imaging technique, it is believed that the most important aspect of an imaging
system is the acquisition of the images. Without a good quality image, any processing would be
meaningless. In this section the implementation of a nondestructive and noninvasive means of analytical
imaging capable of acquiring uninterpolated high resolution images is introduced. The aim is to
complement the analytical information gathered from more established characterization techniques
introduced in the previous sections. The imaging system is used for high-resolution multispectral
imaging. This system is composed of several key components such as light source, camera, spectral
filters and learning sample. In light of the discussion on the building of analytical information database
on pigments and dyes, the important aspects relating to the learning sample would be explored. However,
the method used for multispectral imaging would be introduced.
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Figure 6: A simple representation of the radiation and matter interaction.
Multispectral images were taken using a high-resolution flat-bed scanner designed and
developed at Kyoto University. A schematic representation of the system is depicted by Figure 7. The
scanner is capable of imaging virtually any size of object with very high spatial and spectral resolutions.
The scanning spatial resolution is categorized into three regimes. These include, low resolution, high
resolution and ultrahigh resolution imaging. Low resolution scanning produces images ranging from 300
to 600 dpi (42-85 μm/pixel); high resolution scanning starts above 600 dpi up to 1000 dpi (25 μm/pixel);
and ultrahigh resolution scans images above 1000 dpi up to 3000 dpi (8 μm/pixel). To put this in
perspective, a high-end DSLR with an out-of-the-box lens kit normally produces images at 250 dpi
while an office document scanner scans at 300 dpi then interpolates the image to produce the published
specification of higher resolution scans. Once the image is interpolated, a lot of analytical information is
lost and cannot be recovered. Another, analogy is that a true high resolution image is achieved with
optical zooming while an interpolated high resolution images is digitally zoomed. In the case of the
scanner used in this study, all the images are produced at true resolution with minimal post-processing to
preserve the analytical information saved on the pixels of the images.
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Figure 7: Schematic representation of the high-resolution scanner used for multispectral imaging.
The multispectral images were captured with a monochromatic CMOS line-camera using
spectral-cutting and band-pass filters. A total of eight images were taken which contain spectral
information from 380-850 nm. The images were used to reconstruct spectral data cubes with a 5-nm
resolution. The spectral data were then used to reconstruct spectral reflectance and colorimetric
information. Referring to the physical model shown in Figure 6, it may be inferred that the sensor
response of an imaging device when an object is irradiated with visible and near infrared radiation is
proportional to its spectral reflectance. The sensor response, characterized by the image pixels, can be
mathematically expressed as a function of the object’s spectral reflectance, camera sensitivity, light
source spectral radiance and system error. This is shown in Eq.6.1:
eCp d)()()( rL Eq.6.1
p is an M 1 sensor response vector from the M channel sensor, C(λ) is an M 1 vector of spectral
sensitivity of the sensor, L(λ) is the spectral radiance of the illumination, r(λ) is the spectral reflectance
of the object, and e is an M 1 additive noise vector. For mathematical convenience, Eq.6.1 can also
be expressed in vector form as follows:
eCLrp Eq.6.2
where C is an M N matrix of spectral sensitivity of the sensor, L is an N N diagonal matrix of
spectral radiance of the light source, and r is an N 1 spectral reflectance vector of the target. This
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expression implies that there is a linear relationship between the sensor response and spectral reflectance
of the target. Therefore the transfer function from sensor response to spectral reflectance can be
expressed as a matrix. There are several ways to solve this relationship. It can be either direct or indirect
[33]. Direct method is the most accurate technique for spectral reconstruction but requires a priori
knowledge of the light source characteristics and camera sensitivity. This is not often practical since
there is no guarantee that the sensitivity function will not change due to wear and tear of the equipment.
This warrants the regular measurement of the required spectral characteristics and sensitivity of the
imaging components. An example of a popular direct method is the Wiener estimation. Since reliability
and efficiency are required when doing measurements in situ, a more practical approach is necessary. In
this study, an indirect method of solving the vector relationship between the sensor response and spectral
reflectance is implemented. The technique is based on Moore-Penrose pseudoinverse. In this method,
the vector relationship is solved without the prior knowledge of the spectral characteristics of the system
by using a learning sample. The learning sample can be used to estimate a conversion matrix to
approximate the camera and light source spectral characteristics without having to worry about systemic
changes. This makes the method device independent.
Since the samples characterized in this study are Japanese pigments, a specially designed and
selected palette of Japanese organic and inorganic mineral pigments was used as the learning sample.
The learning sample is composed of 173 pigments. They represent a wide variety of pigments including
natural and artificial; organic and inorganic; ancient and modern; and a broad spectrum of colors with
distinct spectral sensitivities at the infrared region. These learning samples are used to estimate the
spectral reflectance. More information about the learning sample would be discussed in the next section.
Going back to Eq. 6.2, it can be rewritten as,
Hp r Eq.6.3
where H represents the camera and light source spectral characteristics and e is omitted for simplicity.
H in this case represents an M x N matrix with M being the number of spectral channels and N as the
number of spectral interval covering the desired spectral range. The pseudoinverse model is a
modification of the Wiener estimation by regression analysis [4]. In this model, a matrix W is derived by
minimizing from a known spectral reflectance of a learning sample, R, and the corresponding
pixel values, P, captured at a certain spectral band. The matrix W is given by Eq.6.4:
1)( tt PPRPRPW Eq.6.4
Where P+
represents the pseudoinverse matrix of P. By multiplying the derived matrix W to the pixel
value of the target image, p, the spectral reflectance can be estimated using Eq.6.5:
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pr W = ˆ Eq.6.5
The size of the matrices used in Eq.6.4 and Eq.6.5 is a function of the number of learning
sample k, number of multispectral bands M and number of spectral reflectances N. In this study, the
value of M and N depends on the spectral range and number of filters used. The number of filters used is
M=8 while N is either 95 for the 5-nm interval spectral reconstruction between 380-850 nm. Since the
images have high spatial and spectral resolution, the ROI for spectral reflectance reconstruction is
reliable up to pixel level. This enables spectral measurement at spatial resolutions which are not possible
with conventional spectrometers.
b. Japanese pigments and dyes as analytical imaging learning sample
The learning sample is one of the most important components of the analytical imaging system
developed in this study. As discussed in the previous section, this helps approximate the camera and
light source characteristics in reconstructing spectral reflectance and color images from multispectral
images. In a way, using a learning sample is a much simpler way of solving the linear relationship
between the recorded sensor response with the interaction between the light source and the material. In
the past, researches have used standard test color charts like the Kodak Q60, the IT8 color chart and the
Gretag-Macbeth color checker just to name a few as learning sample [34-35]. The advantage of using
these charts is that it contains wide variety of color patches. This is a good sample for colorimetry.
However, since they are not produced using natural colors, they do not possess a correct representation
of natural materials. Their usability is confined in the visible region and may therefore not be suitable
for spectroscopy beyond this region. The spectroscopic technique presented in this study can cover the
visible to the near infrared region. A uniquely designed learning sample was used to reconstruct spectral
reflectance and color image from multispectral image.
The learning sample is composed of 173 commonly used Japanese pigments which includes natural
and artificial pigments; ancient and modern; and organic and inorganic. In addition, it also contains few
dye samples. Japanese pigments are chosen as learning sample because the main target objects where the
analytical imaging system is used for is cultural heritage. The patches of Japanese pigments and dyes
were cut from a book painted by a Japanese painting master and arranged into a color chart which could
be used for scanning. A more detailed procedure on how the learning sample was prepared is described
in the Annex. Figure 8 shows how the pigments and dye patches are arranged. The first five rows are
natural mineral pigments used in the pre-Edo era. It includes copper-based pigments, mercury-based
pigments, iron-based pigments and some organic pigments. The next two rows contain old artificial
pigments and some dyes. The next two rows are natural pigments introduced much more recently and
can be classified as modern pigments (used from Edo period and beyond). Rows J to M are modern
artificial pigments and the last row are metallic pigments. Metallic pigments like silver and gold are
included in the learning sample since they are commonly used pigments especially in Japanese arts.
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Figure 8: A pictogram (a) of the learning sample and a reconstructed color image (b) of the most
commonly used Japanese mineral pigments and dyes.
As mentioned previously, the learning sample is composed of wide variety of pigments and dyes.
The pigments can be classified either according to the type or the period when it was first introduced.
Figure 9 shows the distribution of pigment according to the said classification. It can be seen that natural
and artificial pigments are well represented. Statistically, the distribution is almost 50-50. It was decided
to include both artificial and natural pigments mainly on the basis of spectral reflectance reconstruction.
It was observed that pigments of the same color and similar basic chemical composition may emit
different spectra at the near infrared region [12]. For example, copper-based pigment like malachite and
azurite produces completely different spectra for natural and artificial pigment even though the colors
are exactly the same. Since the visible spectra are the same, it is difficult to tell them apart but at the near
infrared region, they are easily distinguishable. This is an important aspect of the analytical imaging at
the near infrared region.
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Figure 9: Pie charts of the categorical distribution of the pigments in the learning sample: one is sorted
in terms of the nature and type of pigment or dye (a) and the other is sorted according to era or time
period (b) when the pigment was first introduced.
The pigment distribution is also given in terms of the period or era with respect to Japanese
history. Some pigments used can be traced way back in the pre-historic era like the Jomon and Kofun
period (~27%). However, most of them are first introduced towards the end of the first millennium when
the Japanese art has flourished through contacts between Korea and China. Since the learning sample
was mainly for Japanese arts, knowing the historical significance of the pigment is important. It is vital
that the most commonly used pigments are well represented to facilitate an accurate reconstruction.
Figure 10 shows the measured spectral reflectance of the pigments according to classification. It can be
seen that the spectra well cover the spectral region from 380-850 nm. The spectra include old artificial
and natural pigment, new artificial natural and mineral pigments, dyes and metallic pigments. In this
study old pigments refer to the eras before the Edo period while new refers to Edo up to the present.
Old Natural
Pigments;
37%
Old
Artificial
Pigments;
13%
Modern
Natural
Pigments;
10%
Modern
Artificial
Pigments;
34%
Metallic
Pigments;
4% Dyes; 2% Jomon; 2%
Kofun- Late
Kofun; 25%
Asuka-Nara;
20%
Meji; 44%
Edo; 6%Kamakura;
1%Muromachi;
2%
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Figure 10: Measured spectral reflectance of the pigments used as learning sample: (a) old natural
pigments; (b) old artificial pigments; (c) dyes; (d) modern natural pigments; (e) modern artificial
pigments; and (f) metallic pigments.
7. Summary
In this paper, the development of analytical information database of Japanese pigments and dyes was
introduced. Different characterization techniques related to material investigation has been applied to
hundreds of pigments and dyes. The techniques employed were either spectroscopic or image-based
characterization which were used to measure different material properties. These include
spectrophotometry (color information and spectral reflectance), XRD (crystallinity and structure),
synchrotron radiation- XRF (elemental composition), SEM (grain size and particle distribution) and
high-resolution multispectral imaging (analytical imaging). Focus was given to multispectral analytical
imaging as new method of characterizing pigments and dyes found in cultural heritage. The proposed
method aims to complement the information extracted from more established technique. The main
advantage of this technique is that it is very practical, mobile and could be used to analyze cultural
heritage in situ non-invasively.
8. References
1. http://www.xrite.com/product_overview.aspx?ID=249
2. Ari Ide-Ektessabi, Jay Arre Toque and Yusuke Murayama, Analysis of cultural heritage by accelerator
techniques and analytical imaging, AIP Conference Proceedings, 1412, pp 5-16, 2011.
0
0.5
1
380 580 7800
0.5
1
380 580 780 0
0.5
1
380 580 780
0
0.5
1
380 580 7800
0.5
1
380 580 780
0
0.5
1
380 580 780
Sp
ect
ral
Waveleng
(a) (b) (c)
(d) (e) (f)
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3. Jun Kaneko, Yusuke Murayama, Jay Arre Toque and Ari Ide-Ektessabi, Non-destructive analytical
imaging of metallic surfaces using spectral measurements and ultrahigh resolution scanning for
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of Traditional Japanese pigments by Multispectral Imaging, Proceedings of SPIE, Vol. 7869, 78690E,
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5. Jay Arre Toque, Yusuke Murayama and Ari Ide-Ektessabi, Polarized Light Scanning for Cultural
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Traditional Japanese Paintings using Multispectral Images. VISIGRAPP 2009, CCIS 68, pp. 119-132,
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Paintings using Digitally Archived Images. Proceedings of SPIE, Vol. 7531, 75310N, 2010.
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Sputtered Calcium Phosphate Thin Film Coatings Evaluated Using Microscratch Testing. Journal of
the Mechanical Behavior of Biomedical Materials, Volume 3, Issue 4, Pages 324-330, 2010.
10. Mariona Rabionet, Jay Arre Toque and Ari Ide-Ektessabi. In vitro evaluation of osteoblast-like cells
on hydroxyapatite-coated porous stainless steel implants by synchrotron radiation X-ray fluorescence.
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stitching of traditional Japanese paintings, Proceedings of IMAGAPP 2009- International Conference
on Imaging Theory and Applications, pp.13-20, 2009.
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imaging of cultural heritage by synchrotron radiation and visible light-near infrared spectroscopy,
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pp.121-128, 2009.
14. Y. Sakatoku, Jay Arre Toque, and A. Ide-Ektessabi, Reconstruction of hyperspectral images based on
regression analysis: optimum regression model and channel selection, Proceedings of IMAGAPP
2009- International Conference on Imaging Theory and Applications, pp.50-54, 2009.
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15. Jay Arre Toque and Ari Ide-Ektessabi. Reconstruction of elemental distribution images from
synchrotron radiation x-ray fluorescence. International Journal of Modern Physics B, Volume 23, No.
4, 557-569, 2009.
16. Ari Ide-Ektessabi, Jay Arre Toque, Kim Min, Yusuke Murayama and Chizu Hoshiai, Analysis of
cultural heritage by synchrotron radiation and accelerator mass spectroscopy, 11th
International
Conference on Applications of Nuclear Techniques, Crete, Greece, Jun 12-18, 2011.
17. Ari Ide-Ektessabi, Jay Arre Toque and Yusuke Murayama, Mesoscopy: A new approach for industrial
in-line inspection, Proceedings of the 4th
Regional Conference on Manufacturing, Yogyakarta,
Indonesia, Nov 9-10, 2011.
18. J.A. Toque and A. Ide-Ektessabi, Characterization techniques for investigating the degradation
mechanisms of traditional Japanese pigments, Technart 2011, Berlin, Germany, April 26-29, 2011.
19. Y. Murayama, J.A. Toque and A. Ide-Ektessabi, High-resolution polarized scanning for analyzing
Japanese folding screens with gold and silver foils, Technart 2011, Berlin, Germany, April 26-29,
2011.
20. G.H. Takaoka, J.A. Toque, C. Hoshiai, A. Ide-Ektessabi, A Cultural and Spiritual Bridge between
Japan and Korea, International Conference on Entertainment Computing, Seoul, Korea, 2010.
21. Ari Ide-Ektessabi and Jay Arre Toque, Image Acquisition Devices for Archiving and Analyzing
Cultural Heritage, The 2nd
AUN/SEED-Net Regional Conference on Manufacturing Engineering,
Bandung, Indonesia, 7-8 December 2009.
22. Ari Ide-Ektessabi and Jay Arre Toque, Application of Analytical Imaging Techniques for
Investigating Cultural Heritage, The 45th
Annual Conference on X-ray Chemical Analysis, 5-6
November 2009, Osaka, Japan, 2009.
23. Jay Arre Toque and Ari Ide-Ektessabi, Characterization of Mineral Pigments used in Traditional
Japanese Paintings, Proceedings of the 27th
Samahang Pisika ng Pilipinas Physics Congress,
Tagaytay, Philippines, SPP-2009-025, 2009.
24. Jay Arre Toque, Yuuichi Murata and Ari Ide-Ektessabi. Effects of High Temperature Heating on the
Discoloration of Traditional Japanese Pigments. Report on Nanotechnology Support Project 2008,
Kyoto University, H20-043.
25. Jay Arre Toque, Ryoichi Nishimura, Ari Ide-Ektessabi. Analysis of cultural heritage by synchrotron
radiation and visible light-near infrared spectroscopy. Photon Factory Activity Report 2007, #25 Part
B, page 255, 2008.
26. Jay Arre Toque, Yuji Sakatoku, A. Ide-Ektessabi. Analytical imaging of materials using multispectral
images. AUN-SEED Net International Symposium, October 23, 2008, JICA Research Institute (Tokyo,
Japan).
27. Jay Arre Toque, Yuji Sakatoku, Masateru Komori, Yusuke Murayama and Ari Ide-Ektessabi.
Analytical Imaging of Cultural Heritage. 1st AUN/SEED-Net Regional Conference in Manufacturing
Engineering, Manila, Philippines, Nov 2008.
Science and Technology for Art Conserving and Recording Tangible, Intangible, and Natural Heritage
Summer School 4-7 September 2012, Manila, Philippines
19
28. Ari Ide-Ektessabi, Jay Arre Toque, Julia Anders and Yuji Sakatoku. Design and construction of a
Total System for High-Resolution Digitization, Non-destructive Analysis and Secure Dynamic
Display of Cultural Heritage. 1st AUN/SEED-Net Regional Conference in Manufacturing
Engineering, Manila, Philippines, Nov 2008.
29. Yuji Sakatoku, Tokuyama Hirokazu, Jay Arre Toque, Julia Anders, Hitoshi Kubota, Yuichi Murata,
Min Kim, Saeko Yamaguchi, Masakazu Kimura, Yoko Kasajima and Ari Ide-Ektessabi. High
resolution imaging system for cultural heritage. 11th
Buddhism Fine Arts History Meeting 2008,
Korea, April 2008.
30. Jay Arre Toque and Ari Ide-Ektessabi. Analytical imaging of single neurons derived from synchrotron
radiation x-ray fluorescence spectra. 9th International Conference on Applications of Nuclear
Techniques, Crete, Greece, June 2008.
31. G. Rhodes, Crystallography Made Crystal Clear, Academic Press. C.A. 2000.
32. Joint Committee on Powder Diffraction Standards (JCPDS), International Center for Diffraction Data,
Swathmore, PA.
33. Shimano N (2006) Opt. Eng. 45, 013201.
34. Shimano, N., Terai, K., Hironaga, M.: Recovery of spectral reflectance of objects being imaged by
multispectral cameras. Journal of Optical Society of America A, 24(10), 3211-3219 (2007).
35. Y. Murakami, K. Fukura, M. Yamaguchi, N. Ohyama, Optics Express, 16(6), 4106-4120 (2008)