eces 682 digital image processing week 6
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ECES 682 Digital Image Processing Week 6. Oleh Tretiak ECE Department Drexel University. Announcements. Midterm has been graded Grades posted on webct Average Select your project! Project due on May 15 Final exam on Monday, June 12. Image Distortion Model. - PowerPoint PPT PresentationTRANSCRIPT
Digtial Image Processing, Spring 2006
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ECES 682 Digital Image ProcessingWeek 6
Oleh TretiakECE DepartmentDrexel University
Digtial Image Processing, Spring 2006 2
Announcements
• Midterm has been graded Grades posted on webct Average
• Select your project! Project due on May 15• Final exam on Monday, June 12
Digtial Image Processing, Spring 2006 3
Image Distortion Model
• Restoration depends on distortion Common model: convolve plus noise Special case: noise alone (no convolution)
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Thoughts on Restoration
• Enhancement vs restoration Enhancement: cosmetic Restoration: substantive In reality, there’s a continuum
• Restoration relies on prior knowledge• Example of restoration
Inverse filtering Noise removal Nonlinear processing
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Chapter 6, Color Image Processing
• Color fundamentals and models• Pseudocolor
Slicing False-color maps Index color Multispectral color models
• Color transformations• Smoothing and sharpening• Color segmentation
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Retinal Physiology and Color
• Human retinas have (at least) four types of photoreceptors Three types of ‘cones’
High light level, high acuity vision Each type of cone has a different spectral response
One type of ‘rods’ Low-light level and peripheral vision
• There is substantive genetic diversity in color receptors Different spectral response of photoreceptor Absence of one of the pigments Many more phenomena...
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Spectral Response of Cones
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Color Matching Theory
• Young’s observation Any uniform color can be matched by projecting three
different light sources onto a screen
• In the 1920’s, an international effort on the part of a number of physicists let to the CIE standard color theory
• The effort attempted to simplify and standardize• There have been many refinements, but the basic
theory still stands• Theory useful for matching pigments (all paint
stores have spectrophotometers) and design of color media systems
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Tristimulus Values
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
I(λ) — spectal energy distribution of a source
X,Y,Z — tristimulus values of the source
X = x(λ)I (λ)dλ400
700
∫Y = y(λ)I (λ)dλ
400
700
∫Z= z(λ)I (λ)dλ
400
700
∫Chromaticities - trichromatic coefficients
x =X
X +Y + Z
y=Y
X +Y + Z
z=Z
X +Y + Zx+ y+ z=1
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Chromaticity Diagram
• From http://www.efg2.com/Lab/Graphics/Colors/Chromaticity.htm
• White is (1/3, 1/3, 1/3)• Y is the subjective
intensity.
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Standard Observer
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Better Subjective Color
• Constant distances in x, y space do not correspond to ‘constant’ changes of color
• A better linear space is provided by the Y-U-V coordinates
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RGB Coordinates
• With the advent of color television, the RGB coordinates were introduced to conveniently produce color on a color cinescope (cathode ray tube)
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RGB Gamut
• Color space produced by a specific set of phosphors or LCD filters is limited
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Constant-Color-Difference Coordinates
• For modulation (analog TV) and encoding (digital TV, JPEG), Y-U-V-like coordinates are produced
• R’, G’, B’ are gamma corrected RGB. These are used in electronic media.
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Chapter 6Color Image Processing
Chapter 6Color Image Processing
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Chapter 6Color Image Processing
Chapter 6Color Image Processing
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Chapter 6Color Image Processing
Chapter 6Color Image Processing
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Chapter 6Color Image Processing
Chapter 6Color Image Processing
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Chapter 6Color Image Processing
Chapter 6Color Image Processing
Digtial Image Processing, Spring 2006 21
Chapter 6Color Image Processing
Chapter 6Color Image Processing
Digtial Image Processing, Spring 2006 22
Chapter 6Color Image Processing
Chapter 6Color Image Processing
Digtial Image Processing, Spring 2006 23
Chapter 6Color Image Processing
Chapter 6Color Image Processing
Digtial Image Processing, Spring 2006 24
Chapter 6Color Image Processing
Chapter 6Color Image Processing
Digtial Image Processing, Spring 2006 25
Chapter 6Color Image Processing
Chapter 6Color Image Processing
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Chapter 6Color Image Processing
Chapter 6Color Image Processing
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Chapter 6Color Image Processing
Chapter 6Color Image Processing
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Chapter 6Color Image Processing
Chapter 6Color Image Processing
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Chapter 6Color Image Processing
Chapter 6Color Image Processing
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Chapter 6Color Image Processing
Chapter 6Color Image Processing
Digtial Image Processing, Spring 2006 31
Chapter 6Color Image Processing
Chapter 6Color Image Processing
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Chapter 6Color Image Processing
Chapter 6Color Image Processing
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Chapter 6Color Image Processing
Chapter 6Color Image Processing
Digtial Image Processing, Spring 2006 34
Chapter 6Color Image Processing
Chapter 6Color Image Processing
Digtial Image Processing, Spring 2006 35
Chapter 6Color Image Processing
Chapter 6Color Image Processing
Digtial Image Processing, Spring 2006 36
Chapter 6Color Image Processing
Chapter 6Color Image Processing
Digtial Image Processing, Spring 2006 37
Chapter 6Color Image Processing
Chapter 6Color Image Processing
Digtial Image Processing, Spring 2006 38
Chapter 6Color Image Processing
Chapter 6Color Image Processing
Digtial Image Processing, Spring 2006 39
Chapter 6Color Image Processing
Chapter 6Color Image Processing
Digtial Image Processing, Spring 2006 40
Chapter 6Color Image Processing
Chapter 6Color Image Processing
Digtial Image Processing, Spring 2006 41
Chapter 6Color Image Processing
Chapter 6Color Image Processing
Digtial Image Processing, Spring 2006 42
Chapter 6Color Image Processing
Chapter 6Color Image Processing
Digtial Image Processing, Spring 2006 43
Chapter 6Color Image Processing
Chapter 6Color Image Processing
Digtial Image Processing, Spring 2006 44
Chapter 6Color Image Processing
Chapter 6Color Image Processing
Digtial Image Processing, Spring 2006 45
Chapter 6Color Image Processing
Chapter 6Color Image Processing
Digtial Image Processing, Spring 2006 46
Chapter 6Color Image Processing
Chapter 6Color Image Processing
Digtial Image Processing, Spring 2006 47
Chapter 6Color Image Processing
Chapter 6Color Image Processing
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Chapter 6Color Image Processing
Chapter 6Color Image Processing
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Chapter 6Color Image Processing
Chapter 6Color Image Processing
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Chapter 6Color Image Processing
Chapter 6Color Image Processing
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Chapter 6Color Image Processing
Chapter 6Color Image Processing
Digtial Image Processing, Spring 2006 52
Chapter 6Color Image Processing
Chapter 6Color Image Processing
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Chapter 6Color Image Processing
Chapter 6Color Image Processing
Digtial Image Processing, Spring 2006 54
Chapter 6Color Image Processing
Chapter 6Color Image Processing
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Chapter 6Color Image Processing
Chapter 6Color Image Processing
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Chapter 6Color Image Processing
Chapter 6Color Image Processing
Digtial Image Processing, Spring 2006 57
Chapter 6Color Image Processing
Chapter 6Color Image Processing
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Chapter 6Color Image Processing
Chapter 6Color Image Processing
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Chapter 6Color Image Processing
Chapter 6Color Image Processing
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Chapter 6Color Image Processing
Chapter 6Color Image Processing
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Chapter 6Color Image Processing
Chapter 6Color Image Processing
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Chapter 6Color Image Processing
Chapter 6Color Image Processing