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Digital Image Processing

Instructor: Hossein PourghassemIslamic Azad University of NajafabadDepartment of Electrical Engineering

Islamic Azad University of Najafabad, Department of Electrical Engineering, Dr. H. Pourghassem 2

ReferencesDigital 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.

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Evaluation

Assignments 5 PointFinal exam 10 PointFinal Project 5 Point

Islamic Azad University of Najafabad, Department of Electrical Engineering, Dr. H. Pourghassem 4

DefinitionsImage ProcessingComputer VisionLow Level Processes: Primitive operations such as image preprocessing to reduce noise, contrast enhancement and image sharpening (input and output of this stage are image).Mid-Level Processes: segmentation, description and recognition (classification). (input is image and output is extracted attribute of image in this stage).High Level Processes: understanding groups of objects (making sense).

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Image FormationImage Formation

World Optics SensorSignal Digitizer

Digital Representation

World realityOptics focus {light} from world on sensorSensor converts {light} to {electrical energy}Signal representation of incident light as continuous electrical energyDigitizerconverts continuous signal to discrete signalDigital Rep. final representation of reality in computer memory

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Initial Examples of ImageryInitial Examples of Imagery

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Digital Image ProcessingDigital Image Processing

Islamic Azad University of Najafabad, Department of Electrical Engineering, Dr. H. Pourghassem 8

The electromagnetic spectrum

Gamma-Ray Imaging.X-Ray Imaging.Ultraviolet Imaging.Visible and Infrared Imaging.Microwave Imaging (Radar).Radio band Imaging.Other Imaging Modalities (Sound).

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Example of Gamma-Ray Imaging

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Example of X-Ray Imaging.

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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 12

Example of Visible Imaging

Microscopic Images ofBiologic material

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Example of Infrared Imaging

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Example of Infrared Imaging

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Example of Microwave Imaging (Radar)

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 16

Radio band Imaging

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Other Imaging Modalities (Ultrasound)

Ultrasound imaging in geological exploration, industry and medicine.

Islamic Azad University of Najafabad, Department of Electrical Engineering, Dr. H. Pourghassem 18

Important Stages in Image ProcessingImage AcquisitionPreprocessing (Enhancement and Restoration):

Enhancement is subjective.Restoration is objective.

SegmentationRepresentation and DescriptionRecognition and InterpretationKnowledge base

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Important Stages in Image Processing

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Image Acquisition

Imaging sensor & capability to digitize the signal collected by the sensor:

Video cameraDigital cameraConventional camera & analog-to-digital converter

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Preprocessing

To improve the image to ensure the success of further processes.

e.g.enhancing contrastremoving noiseidentifying information-rich areas.

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SegmentationTo partition the image into its constituent parts (objects)

Autonomous segmentation (very difficult) Can facilitate or disturb subsequent processes.

Output (representation):Raw pixel data, depicting either boundaries or whole regions (corners vs. texture for example).Need conversion to a form suitable for computer processing.

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Representation & Description

Feature selection (description) deals with extracting:

features that result in quantitative information of interest or

features that are important for differentiating one class of objects from another.

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Recognition & InterpretationRecognition:

To assign a label to an object based on information provided by the descriptors.

Interpretation:To assign meaning to a group of recognized objects.

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Knowledge-Base

Knowledge-base Image ProcessingGuides the operation of each processing module and controls the interaction between modules.Interpret and deduce high level information (semantic features) from low level information feature (visual features).

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Comments

Image enhancement for human visual interpretation usually stops at preprocessing.

Recognition and interpretation are associated with image analysis applications where the objective is automation (automated extraction of information from images).

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Components of a Image Processing System

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Fundamental steps in digital Image processing