Figures%20from%20Gonzalez%20and%20Woods,%20Digital%20Image%20Processing,%20Second%20Edition,%202002.

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Lecture 15

• Figures from Gonzalez and Woods, Digital Image
  Processing, Second Edition, 2002.

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Geometric Transformation (1)
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Geometric Transformation (2)
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Chapter 5 Image Restoration
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Geometric Transformation (3)
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Geometric Transformation (4)

• Tiepoints established by application dependent
  methods
• Physical artifacts (like metallic points)
  embedded on the sensor itself. Produces a known
  set of points (called reseau marks) on the image
  as acquired.
• An image distorted by some other process, e.g.,
  display or image reconstruction can be
  geometrically corrected.

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Chapter 5 Image Restoration
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Gray Level Interpolation

• Above technique can result in noninteger values
  of x and y
• Inferring gray levels can gray level
  interpolation
• Two techniques
• Nearest neighbor interpolation (zero order
  interpolation)
• Bilinear interpolation from four nearest points

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Chapter 5 Image Restoration
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Chapter 5 Image Restoration
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Color Image Processing

• Two general types discussed
• Full-color acquired with full color sensor such
  as a TV camera
• Psuedo-color Problem of assigning a color to a
  particular monochrome intensity or range of
  intensities
• Until recently almost all color processing was
  psuedo-color,but full color sensors and hardware
  are now available at reasonable prices

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Description of Light Source

• Chromatic light spans EM spectrum from 400 to 700
  nm.
• Three qualities used to describe light source
• Radiance-total amount of energy from source
  (measured in watts)
• Luminance- energy an observer perceives from
  source (measured in lumens)
• Brightness- Embodies notion of intensity. Hard to
  measure.

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Chapter 6 Color Image Processing
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Chapter 6 Color Image Processing
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Chapter 6 Color Image Processing
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Colors

• Primary colorsred,green,blue
• Secondary colorsmagentaredblue
  cyangreenblue yellowredgreen.
• In pigment a primary color subtracts or absorbs
  primary color of light and reflects or transmits
  other two
• Primary colors of pigment are megenta, cyan, and
  yellow.

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Chapter 6 Color Image Processing
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Chapter 6 Color Image Processing
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Chapter 6 Color Image Processing
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Color Models

• Red, Green, Blue (RGB) color monitors and a
  broad class of video cameras
• CMY (cyan, magenta, yellow) and CMYK (cyan,
  magenta, yellow, black) for color printing
• HIS (hue, saturation, intensity) corresponds
  with how humans describe and interpret color

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Chapter 6 Color Image Processing
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Chapter 6 Color Image Processing
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Chapter 6 Color Image Processing
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Chapter 6 Color Image Processing
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Chapter 6 Color Image Processing
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Chapter 6 Color Image Processing
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Chapter 6 Color Image Processing
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Chapter 6 Color Image Processing