Vladimir Botchko [email protected]
description
Transcript of Vladimir Botchko [email protected]
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Vladimir Botchko [email protected]
Lecture 5. Color Image ProcessingLecture 5. Color Image Processing
Lappeenranta University of Technology (Finland)
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Color Image ProcessingColor Image Processing
Fundamentals Color models Pseudocolor image processing Full color image processing Color transformations Smoothing and Sharpening Color segmentation Noise in color images Color image compression Multispectral image processing
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Fundamentals
Colors in the visible range of wavelengths (upper left), mixtures of light (additive primaries) (upper right) and color bars used in analysis.
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Color models
Relative color gamuts of a dipslay and a printer in XYZ chromaticity coordinate system (right).
Left - XYZ color space.
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Color Image ProcessingColor Image Processing
Fundamentals Color models Pseudocolor image processing Full color image processing Color transformations Smoothing and Sharpening Color segmentation Noise in color images Color image compression Multispectral image processing
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Color models
http://cvision.ucsd.edu/index.htm
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Color models
RGB system, HSI (or HSV) system (right) (I-intensity, V value)
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Color models
Three match curves. RGB system (CIE 1931)(left), XYZ system (CIE 1931)(right)
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Color models
RGB space. The right image is a rotated left image (for correspondence: BL is black, W is white).
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Hue, saturation, intensity system
Y aR cG dBr g b
r g bW PW S
r g b
UV|||W|||
arccos[( / ) ( / ) ( / ) ]
min( , , )
/
26 1 3 1 3 1 3
1 3
2 2 2 1 2
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Color models
Chromaticity
r R R G Bg G R G Bb B R G B
UV|W|/ ( )/ ( )/ ( )
g
r0r g b 1b r b 1
w( / , / )1 31 3
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Color models
Multitriangle representation (left) Luminance, chromaticity (right)
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Color models
Karhunen-Loev system
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Color Image ProcessingColor Image Processing
Fundamentals Color models Pseudocolor image processing Full color image processing Color transformations Smoothing and Sharpening Color segmentation Noise in color images Color image compression Multispectral image processing
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Pseudocoloring
Myocardial perfusion study. Left is a heart attack (blue region increased), right is normal.
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Pseudocoloring. X-rays.
a
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Pseudocoloring Right – three images: elevation relief (upper left), the color coded
magnetic field (higher values are yellowish) (upper right), the composition of first two. Left – underpainting revealed through color dipslay (Prof. L. MacDonald, Derby University,GB).
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Thematic classification of six-band satellite imagery using a minimum distance classifier
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Color Image ProcessingColor Image Processing
Fundamentals Color models Pseudocolor image processing Full color image processing Color transformations Smoothing and Sharpening Color segmentation Noise in color images Color image compression Multispectral image processing
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Painting Restoration. A Queen house , London. The part of painting was copied from another painting (upper right) and
used for restoration of the lost painting part.
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Color Image ProcessingColor Image Processing
Fundamentals Color models Pseudocolor image processing Full color image processing Color transformations Smoothing and Sharpening Color segmentation Noise in color images Color image compression Multispectral image processing
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Color segmentation
Image segmentation based on color feature: burnt forest area, forest fire, dead forest (brown).
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Color Image ProcessingColor Image Processing
Fundamentals Color models Pseudocolor image processing Full color image processing Color transformations Smoothing and Sharpening Color segmentation Noise in color images Color image compression Multispectral image processing
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Color image compression.
Original color image (upper left), compressed image (upper right), error histogram in compression (the error is a delta E – the smallest color noticible difference) and error image (large error values are white).
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Color Image ProcessingColor Image Processing
Fundamentals Color models Pseudocolor image processing Full color image processing Color transformations Smoothing and Sharpening Color segmentation Noise in color images Color image compression Multispectral image processing
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Using a ratio image to enhance road detail (two upper is a multispectral image components)
The third image (lower) is the dividend of the first two
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Color analysis. Color similarity
Brick Ceramic tiles Wooden pieces Car parts
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Color analysis. The Munsell Book of Color contains a set of color patches
http://www.it.lut.fi/research/color/demonstration/demonstration.html
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Color analysis. Metameric spectra. Color is the same at one illumination (left patches) and different at another
illumination (right patches).
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Statistical Analysis of Natural ImagesUpper curve is mean, lower curve is standard deviation
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http://www.techexpo.com/WWW/opto-knowledge/ for previous picture site.http://stargate.jpl.nasa.gov/lctf/ for this picture site.