This document discusses colour image processing. It begins by defining colour fundamentals, noting that colour simplifies object identification and humans can recognize thousands of colours. It then describes several colour models: RGB uses additive colour mixing with red, green and blue primaries; CMY and CMYK are subtractive models used in printing with cyan, magenta, yellow and black inks; HSI represents colour in hue, saturation and intensity. The document explains that pseudo-colour processing assigns colours to grey values based on criteria to enhance subtle details and variations that are difficult to distinguish in greyscales.

1. GUIDED BY: PREPARED BY:
Prof. R.G.Patel Vijay Yadav (140403111014)
Prof.N.L.Rudani Ravi chaudhri(140403111016)
Sankalchand Patel collage of engineering
Subject : Fundamentals Images Subjectcode2171001
Prosessing

2. Colour Image Processing

3. Contents
 Colour fundamentals.
 Colour models.
 Pseudo-colour image processing.

4. ● Color :- three essential elements must be present: light, an
illuminated object, and an observer
● The use of colors in image processing is very important due
to :
o Color is powerful descriptor that simplifies object
identification
o Humans can recognize thousands of color compared to
only two dozen of gray levels.
● The beam of sun light is consisting of continuous spectrum of
colors ranging from violet at one end to red at the other end
(the experiment of the prism)
Color fundamentals

5. Color Modals
 Is an abstract mathematical model describing the way colors can be represented as tuples of
numbers, typically as three or four values or color components.
 When this model is associated with a precise description of how the components are to be
interpreted (viewing conditions, etc.), the resulting set of colors is called color space.
 Type of color modal.
• RGB color model.
• NTSC color modal.
• YcbCr color modal.
• CMY and CMYK color modal.
• HIS color modal.

6. • RGB Model
RGB color modal

7. • In this model, the primary colors are red, green, and blue.
• It is an additive model, in which colors are produced by adding components, with
white having all colors present and black being the absence of any color.
• This is the model used for active displays such as television and computer screens.
• The RGB model is usually represented by a unit cube with one corner located at
the origin of a three-dimensional color coordinate system, the axes being labeled
R, G, B, and having a range of values [0, 1]. The origin (0, 0, 0) is considered black
and the diagonally opposite corner (1, 1, 1) is called white.
• he line joining black to white represents a gray scale and has equal components
of R, G, B

8. • Color printer and copier
• Deposit colored pigment
on paper
• Relationship with RGB
model:
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C = Cyan
M = Magenta
Y = Yellow
K = Black
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B
G
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C
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CMY and CMYK color modal

9. • Cyan, magenta, and yellow are the secondary colors with respect to the
primary colors of red, green, and blue. However, in this subtractive model,
they are the primary colors and red, green, and blue, are the secondary.
• In this model, colors are formed by subtraction, where adding different
pigments causes various colors not to be reflected and thus not to be seen.
Here, white is the absence of colors, and black is the sum of all of them. This
is generally the model used for printing

10. HSI Color Model
• RGB, CMY models are not good for human
interpreting
 Hue: Dominant color
 Saturation: Relative purity (inversely proportional
to amount of white light added)
 Intensity: Brightness
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Color carrying
information

11. Pseudo colour image processing.
• Assigning colors to gray values based on specified criterion

12. • Although the rods of the eye are sensitive to very low intensities, they have very
limited discrimination between gray levels. Generally, the eye cannot distinguish
more than about 50 gray levels in an image.
• Thus subtle detail can easily be lost in looking at gray scale images. To enhance
variations in gray level and make them more obvious, gray scale images are
frequently pseudo-colored, where each gray scale (generally at least 256 levels
for most displays) are mapped to a color level through a LUT.
• The eye is extremely sensitive to color and can distinguish thousands of color
values in a picture.
• Many different mapping schemes are used so that the variation in color, say from
blue to red, corresponds to human expectation of less to more.

13. Reference
www.google.com
www.wikipedia.com
Reface book
Rafael C. Gonzalez and Richard E. Woods

14. THANK YOU