Digital Image Processing
Instructor: Hossein Pourghassem
Islamic Azad University of Najafabad
Department of Electrical Engineering
References
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Digital Image Processing, Second Edition (Text Book)
Rafael C. Gonzalez and Richard E. Woods.
Fundamentals of Digital Image Processing, A. K. Jain,
Digital Image Processing: Third Edition. William K.
Pratt, 2001 John Wiley & Sons.
Theory and Application of Digital Image Processing, A.
Erhard-Ferron, University of Offenburg.
Digital Image Processing with Application to Digital
Cinema, By K. S. Thyagarajan, Focal Press, Elsevier.
Islamic Azad University of Najafabad, Department of Electrical Engineering, Dr. H. Pourghassem
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Evaluation
ƒ Assignments
ƒ Final exam
ƒ Final Project
5 Point
10 Point
5 Point
Islamic Azad University of Najafabad, Department of Electrical Engineering, Dr. H. Pourghassem
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Definitions
ƒ Image Processing
ƒ Computer Vision
ƒ Low Level Processes: Primitive operations such as
image preprocessing to reduce noise, contrast
enhancement and image sharpening (input and output
of this stage are image).
ƒ Mid-Level Processes: segmentation, description and
recognition (classification). (input is image and
output is extracted attribute of image in this stage).
ƒ High Level Processes: understanding groups of
objects (making sense).
Islamic Azad University of Najafabad, Department of Electrical Engineering, Dr. H. Pourghassem
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Image Formation
World
Optics
Sensor
Signal
Digitizer
Digital Representation
World
reality
Optics
focus {light} from world on sensor
Sensor
converts {light} to {electrical energy}
Signal
representation of incident light as continuous electrical energy
Digitizerconverts continuous signal to discrete signal
Digital Rep.
final representation of reality in computer memory
Islamic Azad University of Najafabad, Department of Electrical Engineering, Dr. H. Pourghassem
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Initial Examples of Imagery
Islamic Azad University of Najafabad, Department of Electrical Engineering, Dr. H. Pourghassem
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Digital Image Processing
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The electromagnetic spectrum
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Gamma-Ray Imaging.
X-Ray Imaging.
Ultraviolet Imaging.
Visible and Infrared Imaging.
Microwave Imaging (Radar).
Radio band Imaging.
Other Imaging Modalities (Sound).
Islamic Azad University of Najafabad, Department of Electrical Engineering, Dr. H. Pourghassem
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Example of Gamma-Ray Imaging
Islamic Azad University of Najafabad, Department of Electrical Engineering, Dr. H. Pourghassem
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Example of X-Ray Imaging.
Islamic Azad University of Najafabad, Department of Electrical Engineering, Dr. H. Pourghassem
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Example of Ultraviolet Imaging
Spectral image of normal
and abnormal corn
Islamic Azad University of Najafabad, Department of Electrical Engineering, Dr. H. Pourghassem
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Example of Visible Imaging
Microscopic Images of
Biologic material
Islamic Azad University of Najafabad, Department of Electrical Engineering, Dr. H. Pourghassem
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Example of Infrared Imaging
Islamic Azad University of Najafabad, Department of Electrical Engineering, Dr. H. Pourghassem
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Example of Infrared Imaging
Islamic Azad University of Najafabad, Department of Electrical Engineering, Dr. H. Pourghassem
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Example of Microwave Imaging (Radar)
ƒ The unique feature of imaging radar is its ability to collect data
over virtually any region at any time, regardless of weather or
ambient lighting conditions.
Islamic Azad University of Najafabad, Department of Electrical Engineering, Dr. H. Pourghassem
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Radio band Imaging
Islamic Azad University of Najafabad, Department of Electrical Engineering, Dr. H. Pourghassem
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Other Imaging Modalities (Ultrasound)
ƒ Ultrasound imaging in geological exploration, industry
and medicine.
Islamic Azad University of Najafabad, Department of Electrical Engineering, Dr. H. Pourghassem
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Important Stages in Image Processing
ƒ Image Acquisition
ƒ Preprocessing (Enhancement and Restoration):
ƒ Enhancement is subjective.
ƒ Restoration is objective.
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Segmentation
Representation and Description
Recognition and Interpretation
Knowledge base
Islamic Azad University of Najafabad, Department of Electrical Engineering, Dr. H. Pourghassem
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Important Stages in Image Processing
Islamic Azad University of Najafabad, Department of Electrical Engineering, Dr. H. Pourghassem
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Image Acquisition
ƒ Imaging sensor & capability to digitize the signal
collected by the sensor:
ƒ Video camera
ƒ Digital camera
ƒ Conventional camera & analog-to-digital converter
Islamic Azad University of Najafabad, Department of Electrical Engineering, Dr. H. Pourghassem
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Preprocessing
ƒ To improve the image to ensure the success of
further processes.
ƒ e.g.
ƒ enhancing contrast
ƒ removing noise
ƒ identifying information-rich areas.
Islamic Azad University of Najafabad, Department of Electrical Engineering, Dr. H. Pourghassem
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Segmentation
ƒ To partition the image into its constituent parts (objects)
ƒ Autonomous segmentation (very difficult)
ƒ Can facilitate or disturb subsequent processes.
ƒ Output (representation):
ƒ Raw pixel data, depicting either boundaries or whole regions
(corners vs. texture for example).
ƒ Need conversion to a form suitable for computer processing.
Islamic Azad University of Najafabad, Department of Electrical Engineering, Dr. H. Pourghassem
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Representation & Description
ƒ Feature selection (description) deals with extracting:
ƒ features that result in quantitative information of
interest or
ƒ features that are important for differentiating one class
of objects from another.
Islamic Azad University of Najafabad, Department of Electrical Engineering, Dr. H. Pourghassem
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Recognition & Interpretation
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Recognition:
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To assign a label to an object based on information
provided by the descriptors.
Interpretation:
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To assign meaning to a group of recognized objects.
Islamic Azad University of Najafabad, Department of Electrical Engineering, Dr. H. Pourghassem
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Knowledge-Base
ƒ Knowledge-base Image Processing
ƒ Guides the operation of each processing module and
controls the interaction between modules.
ƒ Interpret and deduce high level information (semantic
features) from low level information feature (visual
features).
Islamic Azad University of Najafabad, Department of Electrical Engineering, Dr. H. Pourghassem
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Comments
ƒ Image enhancement for human visual interpretation
usually stops at preprocessing.
ƒ Recognition and interpretation are associated with
image analysis applications where the objective is
automation (automated extraction of information from
images).
Islamic Azad University of Najafabad, Department of Electrical Engineering, Dr. H. Pourghassem
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Components of a Image Processing System
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Fundamental steps in digital Image processing
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