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#
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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
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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
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What is a Digital Image?
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)
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What is a Digital Image?
Images Pixels
Pixel values typically represent gray levels,
colours, heights, opacities etc
1 pixel
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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)
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What is Digital Image Processing?
The field of Digital Image
Processing refers to the
processing of digital images
using digital computers.
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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.
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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.
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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.
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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).
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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.
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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
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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
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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
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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
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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
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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
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Fields that use DIP
The Light (electromagnetic wave)
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Fields that use DIP
Different Imaging Modalities
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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.)
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Fields that use DIP
Material Research
Scanning Electron Microscope (SEM)
Tungsten filament
After failure
250x
Damaged IC circuit
2500x
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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
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Fields that use DIP
Oil/Gas Exploration
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Some Applications of DIP
Medical Imaging
Quality control system
Surveillance
Law Enforcement
Artistic Effects
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Some Applications of DIP
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Some Applications of DIP
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?
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Some Applications of DIP
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
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Some Applications of DIP
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
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Some Applications of DIP
Artistic effects are
used to make images
more visually
appealing, to add
special effects and to
make composite
images
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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 .
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Fundamental Steps in DIP
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.
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Fundamental Steps in DIP
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Components of DIP System
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Next time
Digital Image Fundamentals
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