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Lecture 12. Figures from Gonzalez and Woods, Digital Image Processing, Second Edition, 2002. Image Restoration. Chapter 5 Image Restoration. Spatial and Frequency Properties of Noise. Assumptions about noise Noise is independent of spatial coordinates (except spatially periodic noise)
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Lecture 12 Figures from Gonzalez and Woods, Digital Image Processing, Second Edition, 2002.
Chapter 5 Image Restoration
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
Chapter 5 Image Restoration
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
Chapter 5 Image Restoration
Chapter 5 Image Restoration
Chapter 5 Image Restoration
Chapter 5 Image Restoration
Chapter 5 Image Restoration
Chapter 5 Image Restoration
Chapter 5 Image Restoration
Chapter 5 Image Restoration
Chapter 5 Image Restoration
Chapter 5 Image Restoration
Chapter 5 Image Restoration
Chapter 5 Image Restoration
Adaptive Spatial Filters • Local noise reduction filter • Adaptive Mean filter
Chapter 5 Image Restoration