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SPECTRAL COLOR IMAGING. Jussi Parkkinen Markku Hauta-Kasari IPCV 2006 August 23 th , 2006 Budapest, Hungary. Color image formation in human eye. Reproduction of color images on displays. Display characterictics. Laptop, white color on display. Color Gamut presented by. - PowerPoint PPT Presentation
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SPECTRAL COLOR IMAGING
Jussi ParkkinenMarkku Hauta-Kasari
IPCV 2006August 23th, 2006
Budapest, Hungary
Color image formation in human eye
Reproduction of color images on displays
Display characterictics
Laptop, white color on display
350 400 450 500 550 600 650 700 750 8000
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6x 10
-3 valkoinen kannettava
Multiprimary color displays
Conventional LCD 4-primary Flat-panel LCD2x2-tiled, 2000x2000pixels rear-projection6-primary display
Stacked front-projection 6-primary DLP display
y
x
Visible Color for Human Eye
Color Gamut presented by Multiprimary color display
Color Gamut presented by RGB display system
RGB-filters
High and low pass filters
Multiprimary display
6 filters for
Literature• Wyszecki and Stiles: Color Science. John Wiley & Sons,
2000.– The “Bible” of Color Science. Not new anymore, but basics of
standard color science and basics of color are valid material.• Roy Berns: Billmeyer and Saltzman's principles of color
technology. John Wiley & Sons, New York (NY), 2000.– Good and clear introduction to the color and related technologies.
• Hardeberg: Acquisition and reproduction of color images : colorimetric and multispectral approaches. Dissertation.com, 2001 – Jon Yngve’s PhD thesis, good overview on spectral approach and
some methods there.• Mark Fairchild: Color Appearance Models. Addison
Wesley, Reading (MA), 1998.– Explains methods to be used for reproduction of colors to look
correct
SPECTRAL IMAGE APPLICATIONSJussi Parkkinen
Markku Hauta-Kasari
IPCV 2006August 23th, 2006
Budapest, Hungary
Applications areas of spectral imaging• Medical imaging, telemedicine*
• Cultural heritage study and digital museums*
• Paper industry*
• Printing industry*
• Textile industry• eCommerce• Plastic industry*
• Cosmetic industry• Display technology*
Testimage for printing quality test (newspaper)
Some sample spectra for original and print
Example: printing inks and measurement
Example: spectral measurements
Same ink in same paper(different amount of ink)
Comparison between pre-print and print
pre-print print
color difference
Mean reflectance spectra (Jacket)Mean whole image
Ref
lect
ance
pre-print
Examination of metameric inkCourtesy by Yoichi Miyake
Color image With long pass filter>645nm
Passport of Japan (Personal page)
Example of fluorescent colors
Examples: color characterization
Videoconferencing using web-cam
Webcam color correction
Original image Color calibrated image
Simulation of illuminant change
Spectral component images (400, 550,
700 nm)
Church
Observation of Spectral Reflectance
OriginalOnceTwiceThree Times
Example of co-operation with local industry: Tulikivi Co. Ltd. Crevice analysisImage optimization for a screen
IMAGE OF ORIGINAL SAMPLE
IMAGE OF SRGB-REPRODUCTION
ON CRT DISPLAY
IMAGE OF METAMERICCOLOR REPRODUCTION
ON CRT DISPLAY
Figure 3Figure 3. . Differences between original and metameric reproduction (especially lower and upper parts)
are because of uneven illumination of the original sample when picture was taken.
Figure 4Figure 4. . Original printed sample in the middle.
Spectral imaging of displays
On the left ImSpector spectral camera and a 45 degree angle mirror. On the right HP laptop display and Nokia cellular phone display.
Spectral images transformed into sRGB
Laptop LCD display Cellular phone display
Principal component analysis of spectral images
1-4
Laptop LCD display Cellular phone LCD display
5-8
9-12
1316
17 20
Acquiring of spectral face images
Part of the database
Spectral color enhancementapplied to “psoriasis vulgaris”
natural color Enhancement (550nm band)
• Skin lesion apparently visualized by spectral color enhancement
Creation of color surface coating for gray level objects
•Colors of cherries, red apples and a blue pen were picked and used for coloring the cylinder.
CCDcamera
AOTF
Lens
Halogen Lamp (pole)
Plants
Experimental setup
no_ozoneozone
Before ozone exposure ( 0 hours)
Slide14
ozone exp
visible RED 59 hours
ozone exp
4 hours
⊿NIR had remarkable change in parts where visible damage occurred
3
3invisible NIR
Measurement of soybeanEmission Wavelength (LCTF)
400nm 410nm 600nm
350n
m
Exc
itat
ion
Wav
elen
gth
(G
rati
ng
)
360n
m57
0nm
Total 273 imagesTotal 273 images
Excitation-Emission Matrix
SpectralIlluminator
Spectral Imager
XenonLamp
Grating
Micro-slicer
3D Spectral 3D Spectral Imaging SystemImaging System
CCD
LCTF
Measured at National Food Reserch Institute
Result
Proposed method
spectral image
digital camera image
Sugar Content Map(Assoc Prof S. Nakauchi Toyohashi U of Tech, Japan)
知覚画像 糖度分布可視化画像 BrixMelon0726_28- 1
7
891011121314
15
知覚画像 糖度分布可視化画像 BrixMelon0726_27
7
891011121314
15
Multispectral microscopic image capturing system16-band, 2k x 2k pixels / channel
16-band multispectral camera for still image
Multispectral cameras
6-band HDTV camera for motion picture
Spectral video
• Sequence of spectral images
• Shown as movie on the screen
• Very high memory requirements
• Efficient compression needed
• Shown as RGB or multiprimary
AcknowledgementResearchers in Joensuu Color Group
andDr. P. Laihanen Helsinki U of Tech, FinlandAssoc Prof Y. Manabe NAIST, JapanProf Y Miyake Chiba University, JapanDr. Miyata National Museum of Japan HistoryDr. K. Miyazawa Toyohashi U of Tech, JapanAssoc Prof S. Nakauchi Toyohashi U of Tech, JapanProf G. Nyman University of Helsinki, FinlandMr. E. Torniainen M-Real Company, FinlandAssoc Prof N. Tsumura Chiba University, JapanAssoc Prof M. Yamaguchi Natural Vision Center, Japan