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

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Lecture 12

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

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Image Restoration
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Chapter 5 Image Restoration
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Spatial and Frequency Properties of Noise

• Assumptions about noise
• Noise is independent of spatial coordinates
  (except spatially periodic noise)
• Uncorrelated with respect to image itself (actual
  pixel values)
• These assumptions are not strictly true( X-ray
  and nuclear medicine imaging, for instance.
• Under such assumptions, we have noise density
  functions

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Types of noise typical for these distributions

• Gaussian noise Electronic circuits and sensor
  noise
• Rayleigh noise noise fom range imaging
• Exponential and Gamma Densities Laser imaging
• Impulse noise From situations where quick
  transients, such as faulty switching, take place
  during imaging
• Uniform noise Used for random number generators,
  not really descriptive of applications

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Chapter 5 Image Restoration
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Chapter 5 Image Restoration
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Chapter 5 Image Restoration
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Chapter 5 Image Restoration
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Estimating Noise Parameters
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Spatial Domain Noise Filters(1)
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Chapter 5 Image Restoration
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Spatial Domain Noise Filters(2)
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Chapter 5 Image Restoration
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Spatial Domain Noise Filters(3)
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Spatial Domain Filters (4)
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Spatial Domain Noise Filters (5)
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Adaptive Spatial Filters

• Local noise reduction filter
• Adaptive Mean filter

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Chapter 5 Image Restoration