digital image processing lecture 1 - basu.ac.ir · digital image processing lecture 1 ......

Digital Image Processing

Lecture 1(Introduction)

Bu-Ali Sina UniversityComputer Engineering Dep.

Fall 2011

Introduction

“One picture is worth more than ten thousandpwords”

Outline

� Syllabus� References� Course Plane� Grading and policies� Introduction to image processing

Introduction

Syllabus

MSRT References

References

“Digital Image Processing”, Rafael C.Gonzalez & Richard E. Woods,Addison-Wesley, 2002

Digital Image Processing Using matlabmuya

Recommended journals and conferences

•IEEE tran. On Image processing•Journal of Graphics, Vision and Image Processing(GVIP)•Image and Vision Computing•Computer Vision and Image Understanding•Journal of Visual Communication and ImageRepresentation•International Journal of Computer Vision•Machine Vision and Applications•Journal of Mathematical Imaging and Vision•Graphical Models and Image Processing

Course plan•Image fundamental•Image enhancement (Spatial domain)•Image transform (Fourier, DCT)•Image enhancement (Frequency domain)•Image restoration•Color image processing•Image compression•Morphological image processing•Image segmentation

Grading and PoliciesExams 50%

– Midterm 50% (25% of total) about 15/8/90– Final 50% (25% of total)

Final Project (25%)– One project (deadline is about 31/1/90)

Seminar (15%)Seminar (15%)– Every body presents a seminar (select a subject until

15/8/90)Home works (10%)

– 5 home works

Hours: 8-10 Sun. and Tue. (every two week)

Site: http://Profs.basu.ac.ir/khotanlou

Email:Hassan.khotanlou@gmail.comhkh@basu.ac.ir

Contact: 8257410, 11 (324 )

ContentsThis lecture will cover:

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

processing

What is a Digital Image?A digital image is a representation of a two-dimensional image as a finite set of digitalvalues, called picture elements or pixels

Imag

e P

roce

ssin

g (2

002)

Imag

es ta

ken

from

Gon

zale

z &

Woo

ds, D

igita

l Im

age

Pro

cess

ing

(200

2)

What is a Digital Image? (contH)Pixel values typically represent gray levels,colours, heights, etcRemember digitization implies that a digitalimage is an approximation of a real scene

Imag

e P

roce

ssin

g (2

002)

1 pixel

Imag

es ta

ken

from

Gon

zale

z &

Woo

ds, D

igita

l Im

age

Pro

cess

ing

(200

2)

What is digital image?An image: 2-d function

– I=f(x,y)– I: intensity(or color)– (x,y): coordinate– When (x y) and I are finite and discrete quantitiesWhen (x,y) and I are finite and discrete quantities

-> digital image– pixels, picture elements, image elements, pels

Representing digital images

Pixels

Side story of Lena

1972 playboy: Miss Nov. 1997 Lena

Representing digital images

Matrix form

f(0,0) f(0,1) … f(0,N-1)f(1,0) f(0,1) … f(1,N-1)

……

f(M-1,0) f(M-1,1) … f(M-1,N-1)MxN

bits to store the image = M x N x kgray level = 2k

Sources of digital images

Electromagnetic(EM) energyAcoustic imagingSynthetic (computer generated) imagingSynthetic (computer-generated) imaging

EM images (cont.)The same objects in different EM spectrum

Ultrasound images

Synthetic images

What is a Digital Image? (contH)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”, Opacity)

For most of this course we will focus on grey-scale images

What is Digital Image Processing?Digital image processing focuses on two majortasks

– Improvement of pictorial information for humaninterpretation

– Processing of image data for storage,g g gtransmission and representation for autonomousmachine perception

Some argument about where image processingends and fields such as image analysis andcomputer vision start

What is DIP? (contH)The continuum from image processing tocomputer vision can be broken up into low-,mid- and high-level processes

Low Level Process Mid Level Process High Level ProcessLow Level ProcessInput: ImageOutput: Image

Examples: Noiseremoval, imagesharpening

Mid Level ProcessInput: ImageOutput: Attributes

Examples: Objectrecognition,segmentation

High Level ProcessInput: AttributesOutput: Understanding

Examples: Sceneunderstanding,autonomous navigation

In this course we willstop here

Research fields

Low-level processing

ImageEarly vision

Mid-level processing

High-level processing

processing

Computervision

Early vision

Brain processing

Related fields

Image processing– Inputs and outputs are images– Extract attributes from images

Image analysisComputer vision

– Use computers to emulate human vision– Related to artificial intelligence (AI)

Pattern Recognition

History of Digital Image ProcessingEarly 1920s: One of the first applications ofdigital imaging was in the news-paper industry

– The Bartlane cable picturetransmission serviceIm

age

Pro

cess

ing

(200

2)

– Images were transferred by submarine cablebetween London and New York

– Pictures were coded for cable transfer andreconstructed at the receiving end on atelegraph printer

Early digital image

Imag

es ta

ken

from

Gon

zale

z &

Woo

ds, D

igita

l Im

age

Pro

cess

ing

(200

2)

History of DIP (contH)Mid to late 1920s: Improvements to theBartlane system resulted in higher qualityimages

– New reproductionprocesses basedIm

age

Pro

cess

ing

(200

2)

on photographictechniques

– Increased numberof tones inreproduced images Improved

digital image Early 15 tone digitalimage

Imag

es ta

ken

from

Gon

zale

z &

Woo

ds, D

igita

l Im

age

Pro

cess

ing

(200

2)

History of DIP (contH)1960s: Improvements in computing technologyand the onset of the space race led to a surgeof work in digital image processing

– 1964: Computers used toimprove the quality ofIm

age

Pro

cess

ing

(200

2)

images of the moon takenby the Ranger 7 probe

– Such techniques were usedin other space missionsincluding the Apollo landings

A picture of the moon takenby the Ranger 7 probeminutes before landing

Imag

es ta

ken

from

Gon

zale

z &

Woo

ds, D

igita

l Im

age

Pro

cess

ing

(200

2)

History of DIP (contH)1970s: Digital image processing begins to beused in medical applications

– 1979: Sir Godfrey N.Hounsfield & Prof. Allan M.Cormack share the Nobel

Imag

e P

roce

ssin

g (2

002)

Prize in medicine for theinvention of tomography,the technology behindComputerised AxialTomography (CAT) scans Typical head slice CAT

image

Imag

es ta

ken

from

Gon

zale

z &

Woo

ds, D

igita

l Im

age

Pro

cess

ing

(200

2)

History of DIP (contH)1980s - Today: The use of digital imageprocessing techniques has exploded and theyare now used for all kinds of tasks in all kindsof areas

– Image enhancement/restorationg– Artistic effects– Medical visualisation– Industrial inspection– Law enforcement– Human computer interfaces

Examples: Image EnhancementOne of the most common uses of DIPtechniques: improve quality, remove noise etc

Imag

e P

roce

ssin

g (2

002)

Imag

es ta

ken

from

Gon

zale

z &

Woo

ds, D

igita

l Im

age

Pro

cess

ing

(200

2)

Examples: The Hubble TelescopeLaunched in 1990 the Hubbletelescope can take images ofvery distant objectsHowever, an incorrect mirrormade many of Hubble’smade many of Hubble simages uselessImage processingtechniques wereused to fix this

Examples: Artistic EffectsArtistic effects areused to makeimages more visuallyappealing, to addspecial effects and topmake compositeimages

Examples: MedicineTake slice from MRI scan of canine heart, andfind boundaries between types of tissue

– Image with gray levels representing tissuedensity

– Use a suitable filter to highlight edgesImag

e P

roce

ssin

g (2

002)

g g g

Original MRI Image of a Dog Heart Edge Detection ImageImag

es ta

ken

from

Gon

zale

z &

Woo

ds, D

igita

l Im

age

Pro

cess

ing

(200

2)

Examples: GISGeographic Information Systems

– Digital image processing techniques are usedextensively to manipulate satellite imagery

– Terrain classification– MeteorologyIm

age

Pro

cess

ing

(200

2)

gy

Imag

es ta

ken

from

Gon

zale

z &

Woo

ds, D

igita

l Im

age

Pro

cess

ing

(200

2)

Examples: GIS (contH)Night-Time Lights of theWorld data set

– Global inventory ofhuman settlement

– Not hard to imagineImag

e P

roce

ssin

g (2

002)

gthe kind of analysisthat might be doneusing this data

Imag

es ta

ken

from

Gon

zale

z &

Woo

ds, D

igita

l Im

age

Pro

cess

ing

(200

2)

Examples: Industrial InspectionHuman operators areexpensive, slow andunreliableMake machines do thejob insteadIm

age

Pro

cess

ing

(200

2)

job insteadIndustrial vision systemsare used in all kinds ofindustriesCan we trust them?

Imag

es ta

ken

from

Gon

zale

z &

Woo

ds, D

igita

l Im

age

Pro

cess

ing

(200

2)

Examples: PCB InspectionPrinted Circuit Board (PCB) inspection

– Machine inspection is used to determine that allcomponents are present and that all solder jointsare acceptable

– Both conventional imaging and x-ray imagingare used

Examples: Law EnforcementImage processingtechniques are usedextensively by lawenforcers

– Number plateImag

e P

roce

ssin

g (2

002)

precognition for speedcameras/automated tollsystems

– Fingerprint recognition– Enhancement of CCTV

images

Imag

es ta

ken

from

Gon

zale

z &

Woo

ds, D

igita

l Im

age

Pro

cess

ing

(200

2)

Examples: HCI

Try to make human computerinterfaces more natural

– Face recognition– Gesture recognition

Does anyone remember theuser interface from “MinorityReport”?These tasks can beextremely difficult

Key Stages in Digital Image Processing

ImageRestoration

MorphologicalProcessing

SegmentationImageEnhancement

ImageAcquisition

g

Representation& Description

Enhancement

ObjectRecognition

Problem Domain

Colour ImageProcessing

ImageCompression

Key Stages in Digital Image Processing:Image Aquisition

ImageRestoration

MorphologicalProcessing

SegmentationImageEnhancementIm

age

Pro

cess

ing

(200

2)

ImageAcquisition

g

Representation& Description

Enhancement

ObjectRecognition

Problem Domain

Colour ImageProcessing

ImageCompression

Imag

es ta

ken

from

Gon

zale

z &

Woo

ds, D

igita

l Im

age

Pro

cess

ing

(

Key Stages in Digital Image Processing:Image Enhancement

ImageRestoration

MorphologicalProcessing

SegmentationImageEnhancementIm

age

Pro

cess

ing

(200

2)

ImageAcquisition

g

Representation& Description

Enhancement

ObjectRecognition

Problem Domain

Colour ImageProcessing

ImageCompression

Imag

es ta

ken

from

Gon

zale

z &

Woo

ds, D

igita

l Im

age

Pro

cess

ing

(200

2)

Key Stages in Digital Image Processing:Image Restoration

ImageRestoration

MorphologicalProcessing

SegmentationImageEnhancementIm

age

Pro

cess

ing

(200

2)

ImageAcquisition

g

Representation& Description

Enhancement

ObjectRecognition

Problem Domain

Colour ImageProcessing

ImageCompression

Imag

es ta

ken

from

Gon

zale

z &

Woo

ds, D

igita

l Im

age

Pro

cess

ing

(200

2)

Key Stages in Digital Image Processing:Morphological Processing

ImageRestoration

MorphologicalProcessing

SegmentationImageEnhancementIm

age

Pro

cess

ing

(200

2)

ImageAcquisition

g

Representation& Description

Enhancement

ObjectRecognition

Problem Domain

Colour ImageProcessing

ImageCompression

Imag

es ta

ken

from

Gon

zale

z &

Woo

ds, D

igita

l Im

age

Pro

cess

ing

(200

2)

Key Stages in Digital Image Processing:Segmentation

ImageRestoration

MorphologicalProcessing

SegmentationImageEnhancementIm

age

Pro

cess

ing

(200

2)

ImageAcquisition

g

Representation& Description

Enhancement

ObjectRecognition

Problem Domain

Colour ImageProcessing

ImageCompression

Imag

es ta

ken

from

Gon

zale

z &

Woo

ds, D

igita

l Im

age

Pro

cess

ing

(200

2)

Key Stages in Digital Image Processing:Object Recognition

ImageRestoration

MorphologicalProcessing

SegmentationImageEnhancementIm

age

Pro

cess

ing

(200

2)

ImageAcquisition

g

Representation& Description

Enhancement

ObjectRecognition

Problem Domain

Colour ImageProcessing

ImageCompression

Imag

es ta

ken

from

Gon

zale

z &

Woo

ds, D

igita

l Im

age

Pro

cess

ing

(200

2)

Key Stages in Digital Image Processing:Representation & Description

ImageRestoration

MorphologicalProcessing

SegmentationImageEnhancementIm

age

Pro

cess

ing

(200

2)

ImageAcquisition

g

Representation& Description

Enhancement

ObjectRecognition

Problem Domain

Colour ImageProcessing

ImageCompression

Imag

es ta

ken

from

Gon

zale

z &

Woo

ds, D

igita

l Im

age

Pro

cess

ing

(200

2)

Key Stages in Digital Image Processing:Image Compression

ImageRestoration

MorphologicalProcessing

SegmentationImageEnhancement

ImageAcquisition

g

Representation& Description

Enhancement

ObjectRecognition

Problem Domain

Colour ImageProcessing

ImageCompression

Key Stages in Digital Image Processing:Colour Image Processing

ImageRestoration

MorphologicalProcessing

SegmentationImageEnhancement

ImageAcquisition

g

Representation& Description

Enhancement

ObjectRecognition

Problem Domain

Colour ImageProcessing

ImageCompression

Fundamental steps in DIP

SummaryWe have looked at:

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

processing– Key stages in digital image processing