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

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

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

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 ）

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

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

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

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 ）

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 ）

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

Edges Reflected luminance 40% 80%

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

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

Entire Field of View The ratio of reflectances

Entire Field of View Luminance

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

Physical Model Luminance

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

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

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

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

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.