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DIP Unit 1

The document provides an overview of digital image processing, covering the definition of digital images, their history, and key stages in processing. It highlights various applications in fields such as medicine, law enforcement, and industrial inspection, as well as the importance of image enhancement and restoration. The lecture emphasizes the need for practical experience with tools like Matlab for effective learning in this area.

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0% found this document useful (0 votes)

28 views41 pages

DIP Unit 1

Uploaded by

kundan peddnekar

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Download as PDF, TXT or read online on Scribd

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Digital Image Processing

Unit 1
Digital Image Fundamentals

- Dr. Megha Patil

Contents
This 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 image
processing
– Key stages in digital image processing
What is a Digital Image?
A digital image is a representation of a
two- dimensional image as a finite set of
digital values, called picture elements or
pixels
What is a Digital Image? (cont…)
Pixel values typically represent gray levels,
colours, heights, opacities etc
Remember digitization implies that a digital
image is an approximation of a real scene

1 pixel
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
What is Digital Image Processing?
Digital image processing focuses on two
major tasks
– Improvement of pictorial information for
human interpretation
– Processing of image data for storage,
transmission and representation for
autonomous machine perception
Some argument about where image
processing ends and fields such as
image analysis and computer vision start
What is DIP? (cont…)
The continuum from image processing to
computer vision can be broken up into
low-, mid- and high-level processes
Low Level Process Mid Level Process High Level Process
Input: Image Input: Image Input: Attributes
Output: Image Output: Attributes Output: Understanding
Examples: Noise Examples: Object Examples: Scene
removal, image recognition, understanding,
sharpening segmentation autonomous navigation

In this course we will

stop here
History of Digital Image Processing
Early 1920s: One of the first applications of
Images taken from Gonzalez & Woods, Digital Image Processing (2002)

digital imaging was in the news-

paper industry
– The Bartlane cable picture
transmission service Early digital image

– 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
History of DIP (cont…)
Mid to late 1920s: Improvements to the
Images taken from Gonzalez & Woods, Digital Image Processing (2002)

Bartlane system resulted in higher quality

images
– New reproduction
processes based
on photographic
techniques
– Increased number
of tones in Improved
digital image Early 15 tone digital
reproduced images image
History of DIP (cont…)
1960s: Improvements in computing
Images taken from Gonzalez & Woods, Digital Image Processing (2002)

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
A picture of the moon
in other space missions taken by the Ranger 7
including the Apollo landings probe minutes before
landing
History of DIP (cont…)
1970s: Digital image processing begins
Images taken from Gonzalez & Woods, Digital Image Processing (2002)

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 Typical head slice
Tomography (CAT) scans CAT image
History of DIP (cont…)
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
– Artistic effects
– Medical visualisation
– Industrial inspection
– Law enforcement
– Human computer interfaces
Images taken from Gonzalez & Woods, Digital Image Processing (2002)

Applications – Imaging modalities

Applications: Image Enhancement
One of the most common uses of DIP
Images taken from Gonzalez & Woods, Digital Image Processing (2002)

techniques: improve quality, remove noise

etc
Applications: The Hubble Telescope
Launched in 1990 the
Hubble telescope can take
images of very distant
objects
However, an incorrect mirror
made many of Hubble’s
images useless
Image processing
techniques were
used to fix this
Applications: Artistic Effects
Artistic effects are
used to make
images more
visually appealing,
to add special
effects and to make
composite images
Images taken from Gonzalez & Woods, Digital Image Processing (2002)

X-ray imaging
Applications: Medicine
Images taken from Gonzalez & Woods, Digital Image Processing (2002)

Gamma-ray imaging
Applications: Medicine (cont...)
Applications: Medicine (cont...)
•Radio frequencies
Images taken from Gonzalez & Woods, Digital Image Processing (2002)

•Magnetic Resonance Imaging (MRI)

Images taken from Gonzalez & Woods, Digital Image Processing (2002)

Ultrasound
Applications: Medicine (cont...)
Applications: Medicine (cont...)

3D tomography and rendering with transparencies (1)

Images taken from Gonzalez & Woods, Digital Image Processing (2002)
Applications: Medicine (cont...)

3D tomography and rendering with transparencies (2)

Images taken from Gonzalez & Woods, Digital Image Processing (2002)
Applications: Medicine (cont...)

3D tomography and rendering with transparencies (3)

Images taken from Gonzalez & Woods, Digital Image Processing (2002)

Human brain Cancer cell Ice Block (Human

(128 cross-sections) (256 cross-sections) brain) (128
cryo-sections)
Applications: Medicine (cont...)
Take slice from MRI scan of canine heart,
Images taken from Gonzalez & Woods, Digital Image Processing (2002)

and find boundaries between types of

tissue
– Image with gray levels representing tissue
density
– Use a suitable filter to highlight edges

Original MRI Image of a Dog Heart Edge Detection Image

Applications: GIS
Geographic Information Systems
Images taken from Gonzalez & Woods, Digital Image Processing (2002)

– Satellite imagery
– Terrain classification (LANDSAT)
– Meteorology (NOAA)
Applications: GIS (cont…)
Night-Time Lights of
Images taken from Gonzalez & Woods, Digital Image Processing (2002)

the World data set

(infra red)
– Global inventory of
human settlement
– Not hard to imagine
the kind of analysis
that might be done
using this data
Applications: Industrial Inspection
Human operators are
Images taken from Gonzalez & Woods, Digital Image Processing (2002)

expensive, slow and

unreliable
Make machines do the
job instead
Industrial vision systems
are used in all kinds of
industries
Can we trust them?
Applications: PCB Inspection
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
are used
Applications: Law Enforcement
Image processing
Images taken from Gonzalez & Woods, Digital Image Processing (2002)

techniques are used

extensively by law
enforcers
– Number plate recognition
for speed
cameras/automated toll
systems
– Fingerprint recognition
– Enhancement of CCTV
images
Applications: HCI
Try to make human computer
interfaces more natural
– Face recognition
– Gesture recognition
Does anyone remember the
user interface from “Minority
Report”?
These tasks can be
extremely difficult
Key Stages in Digital Image Processing

Image Morphological
Restoration Processing

Image
Segmentation
Enhancement