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All from Gonzalez-Woods.

CLC

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One picture is worth more than ten thousand words

Anonymous

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Digital Image Processing, Rafael C.

Gonzalez & Richard E. Woods,

Addison-Wesley, 2002

Much ofthe material that follows is taken from this book.

Thankful to authors.

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This lecture will cover: Whatis a digital image?

Whatis digital image processing?

History of digital image processing State ofthe art examples of digital image processing

Key stages in digital image processing

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A digital image is a representation of a two-

dimensional image as a finite set of digital values,

called picture elements or pixels

Im

agestakenfromGonzale

z&Woods,

DigitalImageProcessing(2002)

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Pixel values typically representgray levels, colours,

heights, opacities (non-transparent area, as cornea )

etc

Rememberdigitization implies that a digital image isan approximation of a real scene

1 pixel

Im

agestakenfromGonzale

z&Woods,

DigitalImageProcessing(2002)

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Common image formats include: 1 sample per point (B&W or Grayscale)

3 samples per point (Red, Green, and Blue)

4 samples per point (Red, Green, Blue, and Alpha,

a.k.a. Opacity)

For most ofthis course we will focus on grey-scale

images

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Digital image processing focuses on two majortasks Improvement of pictorial information for human

interpretation

Processing ofimage data for storage,transmission and

representation for autonomous machine perception

Some argument about where image processing ends

and fields such as image analysis and computer

vision start

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The continuum from image processingto computer

vision can be broken up into low-, mid- and high-

level processes

LowLevel Process

Input: Image

Output: Image

Examples: Noise

removal,imagesharpening

Mid Level Process

Input: Image

Output:Attributes

Examples: Object

recognition,segmentation

High Level Process

Input:Attributes

Output: Understanding

Examples: Scene

understanding,autonomous navigation

In this course we will

stop here

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Early 1920s: One ofthe first applications of digital

imaging was in the news-

paperindustry

The Bartlane cable picturetransmission service

Images were transferred by submarine cable between

London and New York

Pictures were coded for cable transfer and reconstructed

atthe receiving end on a telegraph printer

Early digital image

Im

agestakenfromGonzale

z&Woods,

DigitalImageProcessing(2002)

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Mid to late 1920s: Improvements to the Bartlane

system resulted in higher quality images New reproduction

processes based

on photographic

techniques

Increased number

oftones in

reproduced images

Improved

digital image Early 15 tone digital

image

Im

agestakenfromGonzale

z&Woods,

DigitalImageProcessing(2002)

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1960s: Improvements in computingtechnology and

the onset ofthe space race led to a surge of work in

digital image processing

1964: Computers used toimprove the quality of

images ofthe moon taken

by the Ranger 7probe

Such techniques were used

in other space missionsincludingthe Apollo landings

A picture ofthe moon taken

by the Ranger 7 probe

minutes before landingIm

agestakenfromGonzalez&Woods,

DigitalImageProcessing(2002)

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1970s: Digital image processing begins to be used

in medical applications 1979: Sir Godfrey N.

Hounsfield & Prof. Allan M.

Cormack share the Nobel

Prize in medicine forthe

invention oftomography,

the technology behind

Computerised AxialTomography (CAT) scansTypical head slice CAT

image

Im

agestakenfromGonzalez&Woods,

DigitalImageProcessing(2002)

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1980s - Today: The use of digital image processing

techniques has exploded and they are now used for

all kinds oftasks in all kinds of areas

Image enhancement/restoration Artistic effects

Medical visualisation

Industrial inspection

Law enforcement

Human computerinterfaces

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One ofthe most common uses ofDIP techniques:

improve quality, remove noise etc

Im

agestakenfromGonzalez&Woods,

DigitalImageProcessing(2002)

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Launched in 1990 the Hubble

telescope can take images of

very distant objects

However, an incorrect mirrormade many of Hubbles

images useless

Image processing

techniques wereused to fix this

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Artistic effects are used

to make images more

visually appealing,to

add special effects and

to make compositeimages

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Take slice from MRI scan of canine heart, and find

boundaries between types oftissue Image with gray levels representingtissue density

Use a suitable filterto highlight edges

Original MRI Image of a Dog Heart Edge Detection ImageIm

agestakenfromGonzalez&Woods,

DigitalImageProcessing(2002)

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Geographic Information Systems Digital image processingtechniques are used extensively

to manipulate satellite imagery

Terrain classification

Meteorology

Im

agestakenfromGonzalez&Woods,

DigitalImageProcessing(2002)

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Night-Time Lights of the

Worlddata set Global inventory of human

settlement

Not hard to imagine thekind of analysis that might

be done usingthis data

Im

agestakenfromGonzalez&Woods,

DigitalImageProcessing(2002)

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Human operators are

expensive, slow and

unreliable

Make machines do the

job instead

Industrial vision systems

are used in all kinds of

industries

Can we trustthem?

Im

agestakenfromGonzalez&Woods,

DigitalImageProcessing(2002)

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Printed Circuit Board (PCB) inspection Machine inspection is used to determine that all

components are present and that all solder joints are

acceptable

Both conventional imaging and x-ray imaging are used

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Image processing

techniques are used

extensively by law enforcers Number plate recognition for

speed cameras/automatedtoll systems

Fingerprint recognition

Enhancement of CCTV

images

Im

agestakenfromGonzalez&Woods,

DigitalImageProcessing(2002)

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Try to make human computer

interfaces more natural Face recognition

Gesture recognition

Does anyone remembertheuserinterface from Minority

Report?

These tasks can be extremely

difficult

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Image

Acquisition

Image

Restoration

Morphological

Processing

Segmentation

Representation

& Description

ImageEnhancement

Object

Recognition

Problem Domain

Colour Image

Processing

Image

Compression

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Image

Acquisition

Image

Restoration

Morphological

Processing

Segmentation

Representation

& Description

ImageEnhancement

Object

Recognition

Problem Domain

Colour Image

Processing

Image

CompressionIm

agestakenfromGonzalez&Woods,

DigitalImageProcessing(2002)

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Image

Acquisition

Image

Restoration

Morphological

Processing

Segmentation

Representation

& Description

ImageEnhancement

Object

Recognition

Problem Domain

Colour Image

Processing

Image

CompressionIm

agestakenfromGonzalez&Woods,

DigitalImageProcessing(2002)

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Image

Acquisition

Image

Restoration

Morphological

Processing

Segmentation

Representation

& Description

ImageEnhancement

Object

Recognition

Problem Domain

Colour Image

Processing

Image

CompressionIm

agestakenfromGonzalez&Woods,

DigitalImageProcessing(2002)

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Image

Acquisition

Image

Restoration

Morphological

Processing

Segmentation

Representation

& Description

ImageEnhancement

Object

Recognition

Problem Domain

Colour Image

Processing

Image

CompressionIm

agestakenfromGonzalez&Woods,

DigitalImageProcessing(2002)

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Image

Acquisition

Image

Restoration

Morphological

Processing

Segmentation

Representation

& Description

ImageEnhancement

Object

Recognition

Problem Domain

Colour Image

Processing

Image

CompressionIm

agestakenfromGonzalez&Woods,

DigitalImageProcessing(2002)

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Image

Acquisition

Image

Restoration

Morphological

Processing

Segmentation

Representation

& Description

ImageEnhancement

Object

Recognition

Problem Domain

Colour Image

Processing

Image

CompressionIm

agestakenfromGonzalez&Woods,

DigitalImageProcessing(2002)

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Image

Acquisition

Image

Restoration

Morphological

Processing

Segmentation

Representation

& Description

ImageEnhancement

Object

Recognition

Problem Domain

Colour Image

Processing

Image

CompressionIm

agestakenfromGonzalez&Woods,

DigitalImag

eProcessing(2002)

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Image

Acquisition

Image

Restoration

Morphological

Processing

Segmentation

Representation

& Description

ImageEnhancement

Object

Recognition

Problem Domain

Colour Image

Processing

Image

Compression

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Image

Acquisition

Image

Restoration

Morphological

Processing

Segmentation

Representation

& Description

ImageEnhancement

Object

Recognition

Problem Domain

Colour Image

Processing

Image

Compression

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We have looked at: Whatis a digital image?

Whatis digital image processing?

History of digital image processing

State ofthe art examples of digital image processing Key stages in digital image processing