Colour Imaging Lab
       www.ugr.es/local/colorimg
  Departamento de Óptica, Facultad de Ciencias,
Universidad de Granada...
Colour Imaging Lab
                           Universidad de Granada
                             www.ugr.es/~colorimg

Pe...
Colour Imaging Lab
                              Universidad de Granada
                                 www.ugr.es/~color...
Spectral information recovery from RGB
                      responses


● Multispectral image capture
  problem




     ...
Color constancy and illuminant estimation

  Recovering spectral information about objects and illuminants
simultaneously ...
RGB cameras to recover normals, albedo
              and spectral information

Reflected light from objects depends on ref...
RGB cameras to recover normals, albedo
                                and spectral information

         Spectral image a...
Natural illumination

Daylight and skylight spectra have complex and spiky spectral
profiles, with spatially and temporall...
Multispectral system for skylight illumination

Multispectral system: Skylight spectral information at each
pixel of the i...
Illuminant invariants


Color-invariant descriptors:
     Analysis of illuminant invariants in color imaging.
Colour Imaging Lab
                                  Universidad de Granada
                                     www.ugr.e...
Colour Imaging Lab
                            Universidad de Granada
                               www.ugr.es/~colorimg
...
Colour Imaging Lab
                           Universidad de Granada
                             www.ugr.es/~colorimg

In...
Colour Imaging Lab
                         Universidad de Granada
                            www.ugr.es/~colorimg

Instr...
Colour Imaging Lab
                         Universidad de Granada
                           www.ugr.es/~colorimg

Instru...
Colour Imaging Lab
                        Universidad de Granada
                          www.ugr.es/~colorimg

...Teach...
Summer internships 2009




Natalia Lybova                             Yu Hu (China)
(Rusia)




                         ...
Master thesis students in Granada
                        January-June 2010



                                           ...
The EMJD VISOR (Erasmus Mundus Joint Doctorate
                  in VISion, Optics and Robotics)



                      ...
The EMJD VISOR (Erasmus Mundus Joint Doctorate
                  in VISion, Optics and Robotics)
Color Imaging Lab Research Interests 2010
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Color Imaging Lab Research Interests 2010

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Main research interest at our Color Imaging Lab (April, 2010)

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Color Imaging Lab Research Interests 2010

  1. 1. Colour Imaging Lab www.ugr.es/local/colorimg Departamento de Óptica, Facultad de Ciencias, Universidad de Granada, 18071-Granada (SPAIN) Research interests, 9th April 2010
  2. 2. Colour Imaging Lab Universidad de Granada www.ugr.es/~colorimg Permanent staff: Javier Romero Juan Luis Javier Eva M. Valero Nieves Hernández-Andrés Ph.D. students Clara Plata Raul Luzón Juan Ojeda
  3. 3. Colour Imaging Lab Universidad de Granada www.ugr.es/~colorimg Colour vision Colour images Colour discrimination Reflectances Illuminants Imaging devices Chromatic Identification and Color and spectral Calibration frequencies - SMSF reconstruction characterization Chromatic contrast Multispectral Objects under Noise estimation sensitivity images natural light 3D objects Optimal sensors Colour constancy Artificial illuminants Spectral estimation Temporal changes algorithms Color invariants Multispectral Optics correlation imaging Atmospheric optics Colour and Spectral Imaging Education in optics
  4. 4. Spectral information recovery from RGB responses ● Multispectral image capture problem + ● Our approach: camera digital counts calculation (simulated RGB data, with or without added color filters) 700 ri = λ ∑ S (λ )T (λ )Q (λ ) = 400 i
  5. 5. Color constancy and illuminant estimation Recovering spectral information about objects and illuminants simultaneously with an RGB camera. Spectral-imaging learning-based algorithm that directly relates camera sensor outputs and illuminant spectra. 6 4 x 10 5 GFC= 0.9771 RMSE= 0.0274 4 Color diff.= 1.5 AE= 12.2 3 2 1 0 0 5 10 15 20 25 RGB error 0.35 0.3 0.25 Relative units 0.2 0.15 0.1 0.05 0 400 450 500 550 600 650 700 Wavelength (nm)
  6. 6. RGB cameras to recover normals, albedo and spectral information Reflected light from objects depends on reflectance (albedo) and illumination… … and on surface relief.
  7. 7. RGB cameras to recover normals, albedo and spectral information Spectral image acquisition + Photometric- stereo 0.5 0.45 0.4 0.35 0.3 0.25 0.2 400 450 500 550 Wavelenght (nm) 600 650 700 N •Image rendering
  8. 8. Natural illumination Daylight and skylight spectra have complex and spiky spectral profiles, with spatially and temporally variable absorption bands. 0.3 0.2 daylig Low dimension 0.1 ht representation 0 -0 . 1 models: PCA, -0 . 2 ICA, NNMF, … -0 . 3 V1 V2 V3 V4 V5 -0 . 4 380 400 450 50 0 5 50 600 650 700 7 50 78 0 lo n g d e on d a (n m )
  9. 9. Multispectral system for skylight illumination Multispectral system: Skylight spectral information at each pixel of the image Skylight spectra: most basic feature in atmospheric optics: to be used for estimating, for example, the Aerosol Optical Depth (AOD), the Angström Alpha parameter (α) and the Cloud Optical Depth (COD). 0.030 spectral radiance (W/m nmstr) 0.025 2 0.020 0.015 0.010 0.005 0.000 400 500 600 700 wavelength (nm)
  10. 10. Illuminant invariants Color-invariant descriptors: Analysis of illuminant invariants in color imaging.
  11. 11. Colour Imaging Lab Universidad de Granada www.ugr.es/~colorimg Since 2001, we published... International ISI journal papers: 31 • Journal of the Optical Society of America A • Applied Optics • Vision Research • Color Research and Applications • Journal of the Imaging Science and Technology • American Journal of Physics • Optical Review • Displays • J. Math. Imaging and Vision • PNAS (Proceedings of the National Academy of Sciences) Proceedings in International meetings: 34 I+D+I Proyects and contracts: 7 4 from the Spanish Ministry of Science and Innovation 1 from the Junta de Andalucía Excellence projects 2 from private companies (Robotiker-Tecnalia; Chromasens)
  12. 12. Colour Imaging Lab Universidad de Granada www.ugr.es/~colorimg International Conferences 10th Congress of the International Colour Association (AIC’05) 419 papers (208 oral + 211 posters) and 538 participants, 36 sessions, 24 invited speakers Colour vision and ageing, Applied colorimetry, Colour physics, Colour vision, Colour vision with natural images, Colour education, Multispectral colour science, Environmental colour design, Photoreceptors and colour vision mechanisms, Colour appearance, Colour emotion, Camera and displays characterization, Evaluation of image quality, Colour preference, Gamut mapping, Computational colour constancy, Colour in architecture, Art and colour, Colour in computer vision, Colour, culture and design, Colour differences
  13. 13. Colour Imaging Lab Universidad de Granada www.ugr.es/~colorimg Instruments: Liquid Cristal Tunable Filters: VariSpec VIS from CRi (400-720 nm) Narrow band filters and wide band filters Monochrome cameras: Retiga SRV 1394 cooled. RGB cameras: Retiga Q1300C Retiga EXI Fast cooled ProgRes C14 cooled
  14. 14. Colour Imaging Lab Universidad de Granada www.ugr.es/~colorimg Instruments: Scanner 3 D (del Centro de Instrumentación Científica) Hyperspectral Imaging based on Volume Bragg Gratings (PhotonEtc, 400-1000 nm, FOV: 15°x6°) Color samples: Color Checker, Color Checker DC, Munsell, NCS, muestras propias con textura y otros.
  15. 15. Colour Imaging Lab Universidad de Granada www.ugr.es/~colorimg Instruments: Spectroradiometers: • SpectraScan PR650 Photoresearch (380-780 nm) • LI-COR 1800 (300-1100 nm) • GER-2600 from SpectraVista (350-2500 nm) • AvaSpec 2048 SPU from Avantes (360-860 nm) Other instruments (goniocolorimeters, spectrophotometers, ...)
  16. 16. Colour Imaging Lab Universidad de Granada www.ugr.es/~colorimg ...Teaching activities: Primera ventana a la Ciencia “Lo que el ojo no ve” en la 4ª fase del Parque de las Ciencias. Desde Noviembre de 2008 a Agosto de 2009 Optics and Photonics News, May 2009
  17. 17. Summer internships 2009 Natalia Lybova Yu Hu (China) (Rusia) Sweet Khisa (Bangladesh)
  18. 18. Master thesis students in Granada January-June 2010 Yu Hu (China) With MULTISCAN Pierre-Alexandre Jay (France) Talha Ahmed (Pakistan)
  19. 19. The EMJD VISOR (Erasmus Mundus Joint Doctorate in VISion, Optics and Robotics) GUC GUC HW HW UJO UJO UdG UdG UJM UJM UGR UGR UB UB To foster the excellence in theoretical and applied research in the field computer vision, optics, colour science and robotics.
  20. 20. The EMJD VISOR (Erasmus Mundus Joint Doctorate in VISion, Optics and Robotics)
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