Digital Image Processing,3rd ed. Gonzalez Woods www.ImageProcessingPlace.com Chapter 6 Color Image Processing Color Fundamentals and models -Pseudo-Color Image Processing Full-color Image processing 1992-2008 R.C.Gonzalez &R.E.Woods
Digital Image Processing, 3rd ed. www.ImageProcessingPlace.com © 1992–2008 R. C. Gonzalez & R. E. Woods Gonzalez & Woods Chapter 6 Color Image Processing Color Fundamentals and models Pseudo-Color Image Processing Full-color Image processing
Digital Image Processing,3rd ed. Gonzalez Woods www.ImageProcessingPlace.com Chapter 6 Color Image Processing Color is a powerful descriptor that often simplifies object identification and extraction from a scene Humans can discern thousands of color shades and intensities,compared to about only two dozen shades of gray 1992-2008 R.C.Gonzalez R.E.Woods
Digital Image Processing, 3rd ed. www.ImageProcessingPlace.com © 1992–2008 R. C. Gonzalez & R. E. Woods Gonzalez & Woods Chapter 6 Color Image Processing • Color is a powerful descriptor that often simplifies object identification and extraction from a scene • Humans can discern thousands of color shades and intensities, compared to about only two dozen shades of gray
Digital Image Processing,3rd ed. Gonzalez Woods www.ImageProcessingPlace.com Chapter 6 Color Image Processing "Color image processing is divide into two major area. Full-Color Processing The images in question typically are acquired with a full- color sensor Pseudo-Color Processing The problem is one of assigning a color to a particular monochrome intensity or range of intensities 1992-2008 R.C.Gonzalez R.E.Woods
Digital Image Processing, 3rd ed. www.ImageProcessingPlace.com © 1992–2008 R. C. Gonzalez & R. E. Woods Gonzalez & Woods Chapter 6 Color Image Processing Color image processing is divide into two major area: Full-Color Processing The images in question typically are acquired with a fullcolor sensor Pseudo-Color Processing The problem is one of assigning a color to a particular monochrome intensity or range of intensities
Digital Image Processing,3rd ed. Gonzalez Woods www.ImageProcessingPlace.com Chapter 6 Color Image Processing The color that human perceive in an object the light reflected from the object Illumination source scene reflection eye 1992-2008 R.C.Gonzalez &R.E.Woods
Digital Image Processing, 3rd ed. www.ImageProcessingPlace.com © 1992–2008 R. C. Gonzalez & R. E. Woods Gonzalez & Woods Chapter 6 Color Image Processing • The color that human perceive in an object = the light reflected from the object Illumination source scene reflection eye
Digital Image Processing,3rd ed. Gonzalez Woods www.ImageProcessingPlace.com Chapter 6 Color Image Processing Color Fundamentals 。 When a beam of sunlight passes through a glass prism,the emerging beam of light is not white but consists instead of a continuous spectrum of colors ranging from violet at one end to red at the other. FIGURE 6.1 Color INFRARED spectrum seen by passing white light through a prism.(Courtesy VHITE LIGHT of the General Electric Co., OPTICAL PRISM ◆ULTRAVIOLET Lamp Business Division.) 1992-2008 R.C.Gonzalez R.E.Woods
Digital Image Processing, 3rd ed. www.ImageProcessingPlace.com © 1992–2008 R. C. Gonzalez & R. E. Woods Gonzalez & Woods Chapter 6 Color Image Processing Color Fundamentals • When a beam of sunlight passes through a glass prism, the emerging beam of light is not white but consists instead of a continuous spectrum of colors ranging from violet at one end to red at the other
Digital Image Processing,3rd ed. Gonzalez&Woods www.ImageProcessingPlace.com Chapter 6 Color Image Processing Chromatic light spans the electromagnetic spectrum from approximately 400to700nm. 。 No color in the spectrum ends abruptly,but rather each color blends smoothly into the next. X-RAYS INFRA MICRO- T.V RADIO RED WAVES 001nm 0001t 100性 ULTRAVIOLET VISIBLE SPECTRUM NFRARED 300 400 500 600 700 1000 1500 WAVELENGTH [Nanometers) FIGURE 6.2 Wavelengths comprising the visible range of the electromagnetic spectrum. (Courtesy of the General Electric Co.,Lamp Business Division.) 1992-2008 R.C.Gonzalez &R.E.Woods
Digital Image Processing, 3rd ed. www.ImageProcessingPlace.com © 1992–2008 R. C. Gonzalez & R. E. Woods Gonzalez & Woods Chapter 6 Color Image Processing • Chromatic light spans the electromagnetic spectrum from approximately 400 to 700 nm. • No color in the spectrum ends abruptly, but rather each color blends smoothly into the next
Digital Image Processing,3rd ed. Gonzalez Woods www.ImageProcessingPlace.com Chapter 6 Color Image Processing Basic quantities to describe the quality of light source: Radiance:Total amount of energy that flows from the light source (in W). Luminance:A measure of the amount ofenergy an observer perceives from the light source (in Im) Brightness:A subjective descriptor that embodies the achromatic notion of intensity and is practical impossible to measure. 1992-2008 R.C.Gonzalez R.E.Woods
Digital Image Processing, 3rd ed. www.ImageProcessingPlace.com © 1992–2008 R. C. Gonzalez & R. E. Woods Gonzalez & Woods Chapter 6 Color Image Processing Basic quantities to describe the quality of light source: Radiance: Total amount of energy that flows from the light source (in W). Luminance: A measure of the amount of energy an observer perceives from the light source (in lm) Brightness: A subjective descriptor that embodies the achromatic notion of intensity and is practical impossible to measure
Digital Image Processing,3rd ed. Gonzalez&Woods www.ImageProcessingPlace.com Chapter 6 Color Image Processing Primary colors:red(R),green(G),blue(B) Blue:435.8nm;Green:546.Inm;Red:700nm 445nm 535nm 575nm FIGURE 6.3 Absorption of light by the red. Blue Green Red green,and blue cones in the human eye as a function of wavelength. 400 450 500 550 600 650 700nm 盖 ys!ppa 1992-2008 R.C.Gonzalez &R.E.Woods
Digital Image Processing, 3rd ed. www.ImageProcessingPlace.com © 1992–2008 R. C. Gonzalez & R. E. Woods Gonzalez & Woods Chapter 6 Color Image Processing • Primary colors: red(R), green(G), blue(B). Blue: 435.8nm; Green: 546.1nm; Red: 700nm
Digital Image Processing,3rd ed. Gonzalez Woods www.ImageProcessingPlace.com Chapter 6 Color Image Processing The primary colors can a MIXTURES OF LIGHT be added to produce the GREEN FIGURE 6.4 Primary and secondary colors of light. secondary colors YELLOW of light and CYAN pigments. (Courtesy of the General Electric ·A primary color of Co..Lamp MAGENTA Business colorants is defined as Division.) one that subtracts or MIXTURES OF PIGMENTS absorbs a primary color (Subtractive primaries) YELLOW of light and reflects or transmits the other two. GREEN BLACK CYAN BLUE PRIMARY AND SECONDARY COLORS OF LIGHT AND PIGMENT 1992-2008 R.C.Gonzalez R.E.Woods
Digital Image Processing, 3rd ed. www.ImageProcessingPlace.com © 1992–2008 R. C. Gonzalez & R. E. Woods Gonzalez & Woods Chapter 6 Color Image Processing • The primary colors can be added to produce the secondary colors of light. • A primary color of colorants is defined as one that subtracts or absorbs a primary color of light and reflects or transmits the other two
Digital Image Processing,3rd ed. Gonzalez Woods www.ImageProcessingPlace.com Chapter 6 Color Image Processing The characteristics generally used to distinguish one color from another are Brightness,Hue,and Saturation Hue:Represents dominant color as perceive by an observer. Saturation:Relative purity or the amount ofwhite light mixed with a hue Hue and saturation taken together are called chromaticity, and therefore,a color may be characterized by its brightness and chromaticity. 1992-2008 R.C.Gonzalez R.E.Woods
Digital Image Processing, 3rd ed. www.ImageProcessingPlace.com © 1992–2008 R. C. Gonzalez & R. E. Woods Gonzalez & Woods Chapter 6 Color Image Processing The characteristics generally used to distinguish one color from another are Brightness, Hue, and Saturation. Hue: Represents dominant color as perceive by an observer. Saturation: Relative purity or the amount of white light mixed with a hue Hue and saturation taken together are called chromaticity, and therefore, a color may be characterized by its brightness and chromaticity