Digital Image Processing: An Introduction

CSC447: Digital Image

Processing

Chapter 1: Introduction

Prof. Dr. Mostafa Gadal-Haqq M. Mostafa

Computer Science Department

Faculty of Computer & Information Sciences

AIN SHAMS UNIVERSITY

Course Management

Text Book:

Gonzalez & Wood. Digital Image Processing, 2nd ed., Wiley, 2001.

Grading:

Homework & Attendance 10

Midterm Exam 10

Lab Exam & Final Project 15

Final Exam 65

Lab work:

Matlab and C#

2 CSC447: Digital Image Processing Prof. Dr. Mostafa GadalHaqq.

Chap. 1: Introduction

What is a digital image?

Areas of digital image processing?

What is digital image processing?

History of digital image processing

Applications of digital image processing

Components of a digital image

processing system


What is a Digital Image?

Real Images

A real image can be

represented as a two-

dimensional continuous

light intensity function

g(x,y); where x and y

denote the spatial

coordinates and the value

of g is proportional to the

brightness (or gray level)

of the image at that point.

g(x,y)

y

x



Digital Images

A digital image is the

sampling and quantization

of a two-dimensional real

image both in spatial

coordinates and brightness.

A digital image I(m,n) =

samples of g(x,y); where m

and n are integers, and I is

the intensity at m and n .

n

m

I(m,n)



Images Pixels

Pixel values typically represent gray levels,

colours, heights, opacities etc

1 pixel



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)


What is Digital Image Processing?

The field of Digital Image

Processing refers to the

processing of digital images

using digital computers.


What is Digital Image Processing?

The main objectives of DIP are:

Improvement of pictorial information

for human interpretation; and

Processing of image data for

storage, transmission, and

representation for autonomous

machine perception.


DIP Areas

The processing of digital images by computers is usually divided into three areas: Image Processing,

Image Analysis, and

Image Understanding (or Computer Vision).

It may be better to consider the three types of computer processes of digital images as low-, mid-, and high-level processes.


DIP Areas

Low-level (Image Processing ) processes involve primitive operations such as:

image preprocessing to reduce noise,

contrast enhancement, image sharpening.

Image Restoration

Image Compression

A low-level process is characterized by the fact that both its inputs and outputs are images.


DIP Areas

Mid-level (Image Analysis/Understanding ) processing on images involves tasks such as:

segmentation (partitioning an image into regions or objects),

description of those objects to reduce them to a form suitable for computer processing, and

classification (recognition) of individual objects.

A mid-level process is characterized by the fact that its inputs generally are images, but its outputs are attributes extracted from those images (e.g., edges, contours, and the identity of individual objects).


DIP Areas

Higher-level (Recognition/Computer

Vision ) processing involves:

“making sense” of an ensemble of

recognized objects, as in image

analysis, and, at the far end process,

performing the cognitive functions

normally associated with vision.


DIP Areas

In summary:

However, there are no clear boundaries between these areas.

Low-Level Process

Input: Image

Output: Image

Examples: Noise

removal, image

sharpening

Mid-Level Process

Input: Image

Output: Attributes

Examples: Object

recognition,

segmentation

High-Level Process

Input: Attributes

Output: Understanding

Examples: Scene

understanding,

autonomous

navigation


History of DIP

Early 1920s: One of the first applications of digital

imaging was in the news-paper

Industry

The Bartlane cable picture

transmission service

Images were transferred by submarine cable

between London and New York

Pictures were coded for cable transfer and

reconstructed at the receiving end on a telegraph

printer

Early digital image


History of DIP

Mid to late 1920s: Improvements to the

Bartlane system resulted in higher quality

images

New reproduction

processes based

on photographic

techniques

Increased number

of tones in

reproduced images

Improved

digital image Early 15 tone digital

image


History of DIP

1960s: Improvements in computing technology

and the onset of the space race led to a surge of

work in digital image processing

1964: Computers used to

improve the quality of

images of the moon taken

by the Ranger 7 probe

Such techniques were used

in other space missions

including the Apollo landings A picture of the moon taken

by the Ranger 7 probe

minutes before landing


History of DIP

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 for the

invention of tomography,

the technology behind

Computerised Axial

Tomography (CAT) scans Typical head slice CAT

image


History of DIP

1980s - Today: The use of digital image

processing techniques has exploded and they are

now used for all kinds of tasks in all kinds of areas

Image enhancement/restoration

Medical visualisation

Human computer interfaces

Industrial inspection

Surveillance

Artistic effects

Law enforcement


Fields that use DIP

The Light (electromagnetic wave)


Fields that use DIP

Different Imaging Modalities


Fields that use DIP

Light microscope

(a)Taxol (anticancer

agent), magnified 250x.

(b) Cholesterol - 40x.

(c) Microprocessor - 60x.

(d) Nickel oxide thin film-

600x. (e) Surface of audio

CD - 1750x. (f) Organic

superconductor - 450µ.

(Images courtesy

of Dr. Michael W.

Davidson, Florida State

University.)


Fields that use DIP

Material Research

Scanning Electron Microscope (SEM)

Tungsten filament

After failure

250x

Damaged IC circuit

2500x


Fields that use DIP

Medical Imaging

Ultrasound X-Ray Imaging CAT/CT

MRI Gamma ray PET 24 CSC447: Digital Image Processing Prof. Dr. Mostafa GadalHaqq.

Fields that use DIP

Radar Imaging

Landsat Images Space borne radar image

Of mountaines in Tebit

Satellite imaging


Fields that use DIP

Oil/Gas Exploration


Some Applications of DIP

Medical Imaging

Quality control system

Surveillance

Law Enforcement

Artistic Effects



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 trust them?



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



Image processing

techniques are used

extensively by law

enforcers

Number plate

recognition for

speed

cameras/automat

ed toll systems

Fingerprint

recognition

Enhancement of

CCTV images



Artistic effects are

used to make images

more visually

appealing, to add

special effects and to

make composite

images


Fundamental Steps in DIP

Image Acquisition

Modalities for getting the image into the computer

Image Enhancement

Techniques that bring out detail that is obscured,

or simply to highlight certain features of interest in

the image

Image Restoration

Techniques that objectively improve the

appearance of the image based on mathematical

and probabilistic models of image degradation .



Image Compression

Techniques for reducing the storage required to

save an image.

Image segmentation

Techniques that partition an image into its

constituents parts or objects.

Recognition

Techniques that assign a label to an object in the

image based on its descriptors.


Components of DIP System


Next time

Digital Image Fundamentals


Digital Image Processing: An Introduction

Education

Transcript of Digital Image Processing: An Introduction