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#
2CSC447: 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

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

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