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Lightness and Retinex Theory Journal of the Optical Society of America Vol. 61, No. 1 Jan. 1971 Edwin H. Land & John J. McCann

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Outline Introduction Independence of Color Edges Entire Field of View Physical Model The Colored Mondrian Conclusion

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Outline Introduction Independence of Color Edges Entire Field of View Physical Model The Colored Mondrian Conclusion

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Introduction Reflectance （ light or dark ） Color （ long-wave, middle-wave, and short-wave ） Color sensation （ the world & the field of view ） Departure （ for example ： insert a comparison standard ） The light （ the reflectance and illuminance ）

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Outline Introduction Independence of Color Edges Entire Field of View Physical Model The Colored Mondrian Conclusion

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Independence of Color The Mondrian （ avoid superposion ） Refelctance ： minimum = 10% Illuminated by three projectors 1. minimize the diversity when only projector turns on 2. a wider band & more light

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Independence of Color Sharp-cut bandpass filter White rectangle （ L, M, S ＝ 6, 35, 60 ）

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Independence of Color The dark brown area The areas ： bright yellow, blue, gray, lime green, and red The areas after readjusted illumination ： yellow, blue, gray, green, and red Color sensation related the light （ wavelength and luminance of any point ）

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Independence of Color Wearing the goggles ： deep-red, dark- adaptation filter two eyes and only one eye The reports were almost the same as the previous results. Few changed the color name. Retinex ＝ retina ＋ cortex 3 lightness vs. 3 retinexs （ L, M, S ）

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Outline Introduction Independence of Color Edges Entire Field of View Physical Model The Colored Mondrian Conclusion

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Edges Reflected luminance 40% 80%

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Edges Place a pencil over the boundary between the two gray areas.

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Outline Introduction Independence of Color Edges Entire Field of View Physical Model The Colored Mondrian Conclusion

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Entire Field of View The ratio of reflectances

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Entire Field of View Luminance

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Outline Introduction Independence of Color Edges Entire Field of View Physical Model The Colored Mondrian Conclusion

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Physical Model Luminance

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Outline Introduction Independence of Color Edges Entire Field of View Physical Model The Colored Mondrian Conclusion

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The Colored Mondrian Retinex theory ： 3 retinexs Each retinex served by one set of cones

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The Colored Mondrian The black, white, and gray Mondrian the ratio of sequential products The colored Mondrian the ratio of the integrals the weighting factor of the wavelength

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Outline Introduction Independence of Color Edges Entire Field of View Physical Model The Colored Mondrian Conclusion

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The difference The function of retinex theory is to tell how the eye can ascertain reflectance in a field in which the illumination is unknowable and the reflectance is unknown.

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1 Light. 2 Visible Light Wavelengths range from 400 nm to 700 nm Longest wavelength = red Shortest wavelength = violet 1 nm = 1 x 10 -9 m.

1 Light. 2 Visible Light Wavelengths range from 400 nm to 700 nm Longest wavelength = red Shortest wavelength = violet 1 nm = 1 x 10 -9 m.

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