Digital Image Analysis and Processing CPE 0907544 Introduction - - PowerPoint PPT Presentation

• Dr. Iyad Jafar

Digital Image Analysis and Processing CPE 0907544

Introduction Chapter 1

Outline

 What is a digital image?  What is digital image processing?  History of digital image processing  State of the art examples of digital image

processing

 Key stages in digital image processing

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What is a Digital Image?

 An image can be defined as a two-dimensional

function f(x,y) with x and y being the spatial coordinates and f is the amplitude

 A digital image is the representation of an image

using finite and discrete values for x, y and f

 These values are called picture elements or pixels

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x y

What is a Digital Image?

 Pixels’ values typically represent gray levels, colors,

heights, opacities etc

 Remember that digitization implies that a digital

image is an approximation of a real scene

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1 pixel

Actual Digitized

What is a Digital Image?

 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 of this course we will focus on grey-

scale images

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What is Digital Image Processing?

 Generally, DIP refers to the processing of digital

images by a computer

 Two principle application areas for DIP

 Improving

the pictorial information for better interpretation for human or machine

 Processing of image data for storage, transmission and

representation for autonomous machine perception

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What is DIP?

 There is no consensus on the boundaries of DIP  Considering DIP as the field where the input and

• utput are images is not true

 However,

consider three types of computerized processing

In this course we will stop somewhere here Low Level Processing Input: image Output: image Example: Enhancement, noise removal, sharpening Mid Level Processing Input: image Output: attributes of image Example: Segmentation, recognition autonomous navigation high Level Processing Input: image Output: Understanding Example: Scene understanding, autonomous navigation

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History of Digital Image Processing

 Early

1920s: One

• f

the first applications of digital imaging was in the newspaper industry

 The

Bartlane cable picture transmission service

 Images were transferred by submarine

cable between London and NewYork

 Pictures were coded for cable transfer

and reconstructed at the receiving end

• n a telegraph printer

Early digital image

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History of Digital Image Processing

 Mid to late 1920s: Improvements

to the Bartlane system resulted in higher quality images

 New

processes based

• n

photographic techniques

 Increased number of tones in

reproduced images

 These were digital images, yet no

computers were involved ?!

Improved digital image Early 15 tone digital image

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History of Digital Image Processing

 Early 1960s

 Appearance of digital computers capable of performing

DIP tasks and the development of space program motivated the birth of DIP

 For example, computers were used to improve the

quality of images of the moon taken by the Ranger 7 probe in 1964

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History of Digital Image Processing

 Late 1960s - 1970s

 Digital image processing pierced into medical, remote

earth sensing, and astronomy

 1979: the invention of Computerized Axial T

• mography (CAT) by

Sir Godfrey N. Hounsfield & Prof. Allan M.

CAT Head image Satellite image

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History of Digital Image Processing

 1980s –T

• day

 DIP is no longer restricted to medicine and space

applications

 Some new applications  Image enhancement/restoration  Artistic effects  Medical visualisation  Industrial inspection  Law enforcement  Human computer interfaces

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Examples of Fields that Use DIP

 The fields that use DIP are diverse  One way to explore such fields is to categorize

images based on their source

 Electromagnetic energy: visible and invisible  Acoustic energy  Ultrasonic  Electronic  Synthetic images

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Examples of Fields that Use DIP

 The electromagnetic spectrum

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Examples of Fields that Use DIP

 Gamma-Ray imaging

 Nuclear medicine (Positron Emission Tomography – PET)

 Patient is injected with a radioactive material that emits gamma

rays as it decays

 The rays are collected by gamma cameras and the image is

reconstructed  Astronomical Observations

 Gamma rays radiated by outer space objects

Gamma rays of a star

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Examples of Fields that Use DIP

 X-ray Imaging

 Medical diagnosis and industrial inspection

 X-rays are generated when an accelerated electrons hits the

nucleus of an atom in x-ray tube

 The intensity of x-ray drops as it propagates through materials

and is collected on a film at the other end

 CAT is the most popular x-ray imaging system as it is capable of

producing 3D images

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Examples of Fields that Use DIP

 Ultraviolet Imaging

 Fluorescence microscopy

 When the invisible UV hits a fluorescent material, electrons are

excited and elevate to higher levels

 Eventually these electrons move back to a lower level and emits

light in the visible spectrum

 Useful in studying/detecting materials capable of fluorescing

 Astronomical observation

Endothelial Cell The Sun imaged in the ultraviolet band

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Examples of Fields that Use DIP

 Imaging in the visible band

 The most common and familiar and is often used with

visual imaging

 Numerous operations can be performed on the acquired

images (enhancement, inspection, law-enforcement)

 Images are acquired with sensors that are sensitive to

the visible light

Cholesterol Microprocessor Bubbles in clear plastic Automated license plate reading

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Examples of Fields that Use DIP

 Imaging in the infrared band

 Infrared radiation is emitted by

all

• bjects

based on their temperatures

 The amount of radiation emitted by an object increases with

temperature, therefore thermography allows

• ne

to see variations in temperature

 For example

 firefighters use it to see through smoke, find persons, and localize the

base of a fire

 power lines maintenance technicians locate overheating joints and parts

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Examples of Fields that Use DIP

 Imaging in the radio band

 Mainly in medicine and aerospace  Magnetic Resonance Imaging (MRI)

 the patient is placed in a powerful magnet and then exposed to

radio waves that pass through his body

 as a response, radio waves are emitted from the tissues with

different strength based on tissue type and location

MRI image for a knee Radio image for the Crab Pulsar (young neutron star)

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Examples of Fields that Use DIP

 Acoustic Imaging

 Geological exploration, medicine, and industry  Expose the object/area to sound waves and record the

strength of the returning waves which is used to infer the underlying structure using a computer

 Ultrasound imaging is perhaps the most popular

Ultrasound image for a baby

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Examples of Fields that Use DIP

 Computer generated images

 Artistic images, computer graphics, animation

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Key Stages in Digital Image Processing

Image Acquisition Image Restoration Segmentation Morphological Processing

Object Recognition

Image Enhancement

Representation & Description

Problem Domain Colour Image Processing Image Compression

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Key Stages in Digital Image Processing Image Acquisition

Image Acquisition Image Restoration Segmentation Morphological Processing

Object Recognition

Image Enhancement

Representation & Description

Problem Domain Colour Image Processing Image Compression

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Key Stages in Digital Image Processing Image Enhancement

Image Acquisition Image Restoration Segmentation Morphological Processing

Object Recognition

Image Enhancement

Representation & Description

Problem Domain Colour Image Processing Image Compression

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Key Stages in Digital Image Processing Image Restoration

Image Acquisition Image Restoration Segmentation Morphological Processing

Object Recognition

Image Enhancement

Representation & Description

Problem Domain Colour Image Processing Image Compression

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Key Stages in Digital Image Processing Segmentation

Image Acquisition Image Restoration Segmentation Morphological Processing

Object Recognition

Image Enhancement

Representation & Description

Problem Domain Colour Image Processing Image Compression

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Key Stages in Digital Image Processing Morphological Processing

Image Acquisition Image Restoration Segmentation Morphological Processing

Object Recognition

Image Enhancement

Representation & Description

Problem Domain Colour Image Processing Image Compression

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Key Stages in Digital Image Processing Object Recognition

Image Acquisition Image Restoration Segmentation Morphological Processing

Object Recognition

Image Enhancement

Representation & Description

Problem Domain Colour Image Processing Image Compression

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Key Stages in Digital Image Processing Representation & Description

Image Acquisition Image Restoration Morphological Processing Segmentation

Object Recognition

Image Enhancement

Representation & Description

Problem Domain Colour Image Processing Image Compression

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Key Stages in Digital Image Processing Image Compression

Image Acquisition Image Restoration Morphological Processing Segmentation

Object Recognition

Image Enhancement

Representation & Description

Problem Domain Colour Image Processing Image Compression

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Key Stages in Digital Image Processing Colour Image Processing

Image Acquisition Image Restoration Morphological Processing Segmentation

Object Recognition

Image Enhancement

Representation & Description

Problem Domain Colour Image Processing Image Compression

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