Digital Image Processing - University of Ioanninacnikou/Courses/Digital_Image_Processing/2011-201… · – Key stages in digital image processing. 2/17/2012 4 7 What is a Digital

2/17/2012

1

Digital Image Processing

Introduction

Christophoros Nikou

University of Ioannina - Department of Computer Science

[email protected]

Images taken from: R. Gonzalez and R. Woods. Digital Image Processing, Prentice Hall, 2008.Digital Image Processing course by Brian Mac Namee, Dublin Institute of Technology.

2 Introduction

“One picture is worth more than ten thousand words”

Anonymous

C. Nikou – Digital Image Processing (E12)

Anonymous

2/17/2012

2

3 Miscellanea

PrerequisitesPrerequisites– Signals and systems– Matlab

Course Grading


– Assignments (50%, at least 6/10)– Final examination (50%)

4 Bibliography– R. Gonzalez, R. Woods. Ψηφιακή Επεξεργασία Εικόνας, Εκδόσεις Τζιόλα, 2010.

– R. Gonzalez, R. Woods. Digital Ιmage Processing, Prentice Hall, 2008.

– N. Παπαμάρκος. Ψηφιακή Επεξεργασία και Ανάλυση Εικόνας, 2010.


– A. Jain. Fundamentals of Digital Image Processing,Prentice Hall, 1988.

2/17/2012

3

5 Bibliography (cont...)


6 Contents

This lecture will cover:– What is a digital image?What is a digital image?– What is digital image processing?– History of digital image processing– State of the art examples of digital image

processingK t i di it l i i


– Key stages in digital image processing

2/17/2012

4

7 What is a Digital Image?

A digital image is a representation of a two-dimensional image as a finite set of digital g

(200

2)

g gvalues, called picture elements or pixels

& W

oods

, Dig

ital I

mag

e P

roce

ssin


Imag

es ta

ken

from

Gon

zale

z &

8 What is a Digital Image? (cont…)

Pixel values typically represent gray levels, colours, heights, opacities etcg

(200

2)

, g , pRemember digitization implies that a digital image is an approximation of a real scene

1 pixel

& W

oods

, Dig

ital I

mag

e P

roce

ssin


Imag

es ta

ken

from

Gon

zale

z &

2/17/2012

5

9 What is a Digital Image? (cont…)

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

10 What is Digital Image Processing?

Digital image processing focuses on two major tasksj

– Improvement of pictorial information for human interpretation

– Processing of image data for storage, transmission and representation for autonomous machine perception


autonomous machine perceptionSome argument about where image processing ends and fields such as image analysis and computer vision start

2/17/2012

6

11 What is DIP? (cont…)

The continuum from image processing to computer vision can be broken up into low-, p p ,mid- and high-level processes

Low Level ProcessInput: ImageOutput: Image

Examples: Noise

Mid Level ProcessInput: Image Output: Attributes

Examples: Object

High Level ProcessInput: Attributes Output: Understanding

Examples: Scene


premoval, image sharpening

p jrecognition, segmentation

punderstanding, autonomous navigation

12 History of Digital Image Processing

Early 1920s: One of the first applications of digital imaging was in the news-g

(200

2)

g g gpaper industry

– The Bartlane cable picture transmission service

– An image was transferred by submarine cable between London and New York in 3

1921

& W

oods

, Dig

ital I

mag

e P

roce

ssin


cable between London and New York in 3 hours

– Pictures were coded for cable transfer and reconstructed at the receiving end on a telegraph printer

Imag

es ta

ken

from

Gon

zale

z &

2/17/2012

7

13 History of DIP (cont…)

Mid to late 1920s: Improvements to the Bartlane system resulted in higher quality g

(200

2)

y g q yimages

– New reproduction processes based on photographic techniques&

Woo

ds, D

igita

l Im

age

Pro

cess

in


q– Increased number

of tones in reproduced images

192215 tone digital image

(1929)

Imag

es ta

ken

from

Gon

zale

z &


1960s: Improvements in computing technology and the onset of the space race g

(200

2)

gy pled to a surge of work in digital image processing

– 1964: Computers used to improve the quality of images of the moon taken&

Woo

ds, D

igita

l Im

age

Pro

cess

in


images of the moon taken by the Ranger 7 probe

– Such techniques were usedin other space missions including the Apollo landings

A picture of the moon taken 17 minutes before landing in

1964

Imag

es ta

ken

from

Gon

zale

z &

2/17/2012

8


1970s: Digital image processing begins to be used in medical applicationsg

(200

2)

pp– 1979: Sir Godfrey N.

Hounsfield & Prof. Allan M. Cormack share the Nobel Prize in medicine for the invention of tomography, &

Woo

ds, D

igita

l Im

age

Pro

cess

in


the technology behind Computerised Axial Tomography (CAT) scans

Typical head slice CAT image

Imag

es ta

ken

from

Gon

zale

z &


1980s - Today: The use of digital image processing techniques has exploded and p g q pthey are now used for all kinds of tasks in all kinds of areas

– Image enhancement/restoration– Artistic effects

M di l i li ti


– Medical visualisation– Industrial inspection– Law enforcement– Human computer interfaces

2/17/2012

9

17 Imaging modalitiesg

(200

2)&

Woo

ds, D

igita

l Im

age

Pro

cess

in


Imag

es ta

ken

from

Gon

zale

z &

18 Gamma-ray imaging

g (2

002) • Positron Emission

Tomography (PET)

& W

oods

, Dig

ital I

mag

e P

roce

ssin Tomography (PET)


Imag

es ta

ken

from

Gon

zale

z &

• Cygnus Loop natural radiation of the star (exploded 15k years ago)

• Valve of a nuclear reactor

2/17/2012

10

19 X-ray imagingg

(200

2) •Chest X-ray• Absorption of energy

& W

oods

, Dig

ital I

mag

e P

roce

ssin • Absorption of energy

•Angiography• Catheter with contrast medium

•Computed Axial Tomography (CAT)


Imag

es ta

ken

from

Gon

zale

z & Tomography (CAT)

•Manufacturing errors in electronic circuits

•Cygnus Loop

20 Ultraviolet imaging

g (2

002) •Fluorescence

microscopy

& W

oods

, Dig

ital I

mag

e P

roce

ssin microscopy

• Normal corn• Corn infected by smut disease

•Cygnus Loop


Imag

es ta

ken

from

Gon

zale

z &

2/17/2012

11

21 Visible and infrared imagingg

(200

2) •Light microscopy• Taxol (anticancer agent)

& W

oods

, Dig

ital I

mag

e P

roce

ssin • Taxol (anticancer agent)

250x• Cholesterol 40x• Microprocessor 60x• Nickel oxide thin film 600x


Imag

es ta

ken

from

Gon

zale

z & 600

• Surface of audio CD 1750x

• Organic superconductor 450x

22 Visible and infrared imaging (cont.)

Remote sensing– Terrain classification (LANDSAT)

g (2

002)

– Meteorology (NOAA)

& W

oods

, Dig

ital I

mag

e P

roce

ssin


Imag

es ta

ken

from

Gon

zale

z &

LANDSAT thematic bands of Washington DC area Hurricane Katrina, 2005

2/17/2012

12

23 Visible and infrared imaging (cont.)g

(200

2) • Night-time lights of the world

& W

oods

, Dig

ital I

mag

e P

roce

ssin world

• Infrared band• Useful for estimating the

percent of total electrical energy


Imag

es ta

ken

from

Gon

zale

z &


g (2

002) • Night-time lights of the

world

& W

oods

, Dig

ital I

mag

e P

roce

ssin world

• Infrared band• Useful for estimating the

percent of total electrical energy


Imag

es ta

ken

from

Gon

zale

z &

2/17/2012

13

25 Visible and infrared imaging (cont.)g

(200

2) • Industrial inspection• Circuit board controller

& W

oods

, Dig

ital I

mag

e P

roce

ssin • Circuit board controller

• Pill container• Bottle filling• Air pockets in plastic parts

• Burned flakes


Imag

es ta

ken

from

Gon

zale

z & u ed a es

• Intraocular implant• Structured light for

detecting lens deformations (damages at 1 and 5 o’clock)


g (2

002) •Law enforcement

• Fingerprint for database

& W

oods

, Dig

ital I

mag

e P

roce

ssin • Fingerprint for database

search• Automated counting• Bill identification• Licence plate detection

and reading


Imag

es ta

ken

from

Gon

zale

z &

2/17/2012

14

27 Imaging in the microwaveg

(200

2) • Radar is the dominant application• It emits pulses and receives them back at its

& W

oods

, Dig

ital I

mag

e P

roce

ssin It emits pulses and receives them back at its

antenna


Imag

es ta

ken

from

Gon

zale

z &

28 Imaging in the radio band

g (2

002) •Magnetic Resonance Imaging (MRI)

• Patient placed in a magnet and radio wave pulses are emitted

& W

oods

, Dig

ital I

mag

e P

roce

ssin through the body

• Resonance takes place with tissues (e.g. water molecules)


Imag

es ta

ken

from

Gon

zale

z &

2/17/2012

15

29 Imaging in the radio bandg

(200

2) •Astronomy

& W

oods

, Dig

ital I

mag

e P

roce

ssin


Imag

es ta

ken

from

Gon

zale

z &

30 Other imaging modalities

g (2

002) •Ultrasound imaging

& W

oods

, Dig

ital I

mag

e P

roce

ssin


Imag

es ta

ken

from

Gon

zale

z &

2/17/2012

16

31 Other imaging modalities (cont.)g

(200

2) •Electron Microscopy (EM)• Works like a slide projector emitting a beam

& W

oods

, Dig

ital I

mag

e P

roce

ssin • Works like a slide projector emitting a beam

of electrons instead of light• The transmitted beam is projected on a phosphor screen

• The interaction of the beam with the slide produces light which is recorded


Imag

es ta

ken

from

Gon

zale

z & p g

• Scanning Electron Microscopy (SEM)• Transmission Electron Microscopy (TEM)

•Very high magnification (10000x)

32 Other imaging modalities (cont.)

g (2

002)

& W

oods

, Dig

ital I

mag

e P

roce

ssin


Imag

es ta

ken

from

Gon

zale

z &

2/17/2012

17

33 Applications: Image Enhancement

One of the most common uses of DIP techniques: improve quality, remove noise g

(200

2)

q p q y,etc

& W

oods

, Dig

ital I

mag

e P

roce

ssin


Imag

es ta

ken

from

Gon

zale

z &

34 Applications: The Hubble Telescope

Launched in 1990 the Hubble telescope can take images of p gvery distant objectsHowever, an incorrect mirror made many of Hubble’s images useless


Image processing techniques were used to fix this

2/17/2012

18

35 Applications: Artistic Effects

Artistic effects are used to make images more visually appealing, to add special effects and to make composite images


composite images

36 Applications: Medicine

g (2

002) 3D tomography and rendering with transparencies

& W

oods

, Dig

ital I

mag

e P

roce

ssin


Imag

es ta

ken

from

Gon

zale

z &

2/17/2012

19

37 Applications: HCI

Try to make human computer interfaces more natural

– Face recognition– Gesture recognition

Does anyone remember the user interface from “Minority R t”?


Report”?These tasks can be extremely difficult

38 Key Stages in Digital Image Processing

Image Restoration

Morphological Processing

Image Acquisition

Restoration Processing

SegmentationImage Enhancement

Object Recognition


Acquisition

Representation & Description

Recognition

Problem DomainColour Image Processing

Image Compression

2/17/2012

20

39Key Stages in Digital Image Processing:

Image Aquisition

Image Restoration

Morphological Processingg

(200

2)

Image Acquisition



Object Recognition&

Woo

ds, D

igita

l Im

age

Pro

cess

in


Acquisition


Recognition


Image Compression

Imag

es ta

ken

from

Gon

zale

z &


Image Enhancement

Image Restoration


(200

2)

Image Acquisition



Object Recognition&

Woo

ds, D

igita

l Im

age

Pro

cess

in


Acquisition


Recognition


Image Compression

Imag

es ta

ken

from

Gon

zale

z &

2/17/2012

21


Image Restoration

Image Restoration


(200

2)

Image Acquisition



Object Recognition&

Woo

ds, D

igita

l Im

age

Pro

cess

in


Acquisition


Recognition


Image Compression

Imag

es ta

ken

from

Gon

zale

z &



Image Restoration


(200

2)

Image Acquisition



Object Recognition&

Woo

ds, D

igita

l Im

age

Pro

cess

in


Acquisition


Recognition


Image Compression

Imag

es ta

ken

from

Gon

zale

z &

2/17/2012

22


Segmentation

Image Restoration


(200

2)

Image Acquisition



Object Recognition&

Woo

ds, D

igita

l Im

age

Pro

cess

in


Acquisition


Recognition


Image Compression

Imag

es ta

ken

from

Gon

zale

z &


Object Recognition

Image Restoration


(200

2)

Image Acquisition



Object Recognition&

Woo

ds, D

igita

l Im

age

Pro

cess

in


Acquisition


Recognition


Image Compression

Imag

es ta

ken

from

Gon

zale

z &

2/17/2012

23



Image Restoration


(200

2)

Image Acquisition



Object Recognition&

Woo

ds, D

igita

l Im

age

Pro

cess

in


Acquisition


Recognition


Image Compression

Imag

es ta

ken

from

Gon

zale

z &


Image Compression

Image Restoration


Image Acquisition



Object Recognition


Acquisition


Recognition


Image Compression

2/17/2012

24


Colour Image Processing

Image Restoration


Image Acquisition



Object Recognition


Acquisition


Recognition


Image Compression

48 Summary

We have looked at:– What is a digital image?What is a digital image?– What is digital image processing?– History of digital image processing– State of the art examples of digital image

processingK t i di it l i i


– Key stages in digital image processing

Important: Acquire some experience with Matlab.

Documents

Digital Image Processing - University of Ioanninacnikou/Courses/Digital_Image_Processing/2011-201… · – Key stages in digital image processing. 2/17/2012 4 7 What is a Digital