EE409 – Digital Image Processing 2017-2018 Spring
3. Fundamentals of Digital Image Processing
by: Dr. Gökhan Koray GÜLTEKİN (adapted from Dr.S.Gedik’s slides)
Light and the Electromagnetic Spectrum
Three basic quantities
Radiance: Total amount of energy that flows from light source (W)
Luminance: Amount of energy an observer perceives from light source (lumens – lm)
E.g.: Consider a high radiance IR source with significant energy
Zero luminance if an observer does not perceive
Brightness: perception
Subjective
descriptor
of
light
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Image Sensing and Acquisition Images are generated by the combination of
Illumination
EM energy (radar, IR, etc), acoustic
Scene
Buildings, molecules, rocks, human brain, etc.
Depending on the source, illumination
can be reflected from the object: E.g. Planar object can be transmitted through object: E.g. X-rays
Image Sensing and Acquisition
Imaging sensor converts the incoming energy into a voltage which is a combination of
input electrical power sensor material responsive to the energy form
Digital image is obtained by digitizing the sensor response
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Image Sensing and Acquisition Image Acquisition Using a Single Sensor
Photodiode
Output voltage waveform is proportional to light
Image Sensing and Acquisition
Image Acquisition Using a Single Sensor
Laser scanner with reflective mirror
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Image Sensing and Acquisition
Image Acquisition Using a Sensor Strips In-line arrangement of sensors
2D image obtained by a perpendicular linear motion
Image Sensing and Acquisition
Image Acquisition Using a Sensor Strips In-line arrangement of sensors
2D image obtained by a perpendicular linear motion
crisp.nus.edu.sg
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Image Sensing and Acquisition
Image Acquisition Using a Sensor Strips In-line arrangement of sensors
2D image obtained by a circular motion MRI: Magnetic Resonance Imaging CT: Computerized Tomography PET: Positron Emission Tomography
Image Sensing and Acquisition
Image Acquisition Using a Sensor Strips In-line arrangement of sensors
2D image obtained by a circular motion MRI: Magnetic Resonance Imaging CT: Computerized Tomography PET: Positron Emission Tomography
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Image Sensing and Acquisition
Image Sensing and Acquisition
Image Acquisition Using Sensor Arrays Sensors arranged in the form of a 2D array
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Image Sensing and Acquisition
Image Acquisition Using Sensor Arrays
Charge-Coupled-Device (CCD) sensors used in digital cameras
directindustry.com
The response of each sensor is proportional to light energy projected onto the surface Motion is not necessary to obtain a 2D image
Application Areas of DIP
Industry, medicine, biological sciences
Aerial and satellite imagery
Archeology
Law enforecement and defence
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Sources of Images •
A basic categorization by sources of images Images based on radiation from EM spectrum (X-ray, visible, Ir)
Sources of Images
A basic categorization by sources of images Acoustic,
ultrasonic and electronic images
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Sources of Images •
A basic categorization by sources of images Synthetic images and more
Electromagnetic Energy Spectrum
Spectral bands are grouped according to energy per photon Applications ranging from astronomy to law enforcement
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Electromagnetic Energy Spectrum •
•
•
Gamma-Ray Imaging Major uses: Nuclear medicine and astronomical observations Nuclear Medicine Inject a patient with a radioactive isotope that emits gamma rays Gamma ray detectors detect image
Electromagnetic Energy Spectrum
Gamma-Ray Imaging Nuclear Medicine (using a radiactive isotope)
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Electromagnetic Energy Spectrum •
Gamma-Ray Imaging Astronomical observations Natural radiation of the object Cygnus constellation
Electromagnetic Energy Spectrum
Gamma-Ray Imaging Nuclear reactor
Gamma radiation(bright spot) from a reactor valve:
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Electromagnetic Energy Spectrum •
• •
X-Ray Imaging Major uses: Diagnosis, astronomy, inspection and security Among the oldest EM radiation imaging Accelerated electrons radiate X-rays when they hit a nucleus
Electromagnetic Energy Spectrum •
• •
X-Ray Imaging Major uses: Diagnosis, astronomy, inspection and security Among the oldest EM radiation imaging Accelerated electrons radiate X-rays when they hit a nucleus
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Electromagnetic Energy Spectrum •
X-Ray Imaging CT: Computerized Tomography
Electromagnetic Energy Spectrum •
X-Ray Imaging Circuit board inspection for faults in manufacturing
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Electromagnetic Energy Spectrum •
Ultraviolet Band Imaging Main uses: Industrial inspection, biological imaging, astronomical observations, etc.
Fluorspar (Fluorite CaF2) glows when ultraviolet light is directed on it
Electromagnetic Energy Spectrum
İnfected Corn
•
Ultraviolet Band Imaging Main uses: Industrial inspection, biological imaging, astronomical observations, etc. Fluorspar (Fluorite CaF2) glows when ultraviolet light is directed on it
Normal Corn
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Electromagnetic Energy Spectrum •
Visible and IR Bands Main uses: From microscopy to law enforcement
Minimum
Far
Electromagnetic Energy Spectrum •
Visible and IR Bands Microscopy
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Electromagnetic Energy Spectrum •
Visible and IR Bands Aerial
Electromagnetic Energy Spectrum •
Visible and IR Bands Weather observation
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Electromagnetic Energy Spectrum
•
Visible and IR Bands Thermal imaging: Human settlement
Electromagnetic Energy Spectrum •
Visible and IR Bands Thermal imaging: Surveillance
thermalvideo.com
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Electromagnetic Energy Spectrum •
Visible and IR Bands Visible band: Automated inspection
Electromagnetic Energy Spectrum
•
Visible and IR Bands Visible band
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Electromagnetic Energy Spectrum • •
Microwave Band Main use: Radar ( Radio Detection and Ranging) Imaging regardless of weather conditions, illumination and even through vegetation, ice and sand
wikipedia.org
Electromagnetic Energy Spectrum
Microwave Band
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Electromagnetic Energy Spectrum • •
Radio Band Main uses: Medicine and astronomy MRI: Magnetic Resonans Imaging • •
Place patient in a magnet Explore tissue structure
Electromagnetic Energy Spectrum • •
Radio Band Main uses: Medicine and astronomy MRI: Magnetic Resonans Imaging • •
Place patient in a magnet Explore tissue structure
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Electromagnetic Energy Spectrum
Comparison Example
Totally different views of the source
Other Imaging Modalities
• • •
Although imaging in EM spectrum is dominant there are other modalities Acoustic imaging Electron microscopy Synthetic imaging
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Other Imaging Modalities Acoustic Imaging Main uses: Geological exploration, industry and medicine Send and analyze received sound waves
•
•
Other Imaging Modalities •
Acoustic Imaging Medicine
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Other Imaging Modalities • •
Electron Microscopy Shine a beam of electrons over the surface of interest High magnification capability
Other Imaging Modalities
Synthetic Imaging Computer generated
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Main Applications of DIP 1.
Two principal applications Improvement of pictorial information for human interpretation E.g. Contrast Enhancement
Main Applications of DIP 1.
Two principal applications Improvement of pictorial information for human interpretation E.g. Motion Deblurring
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Main Applications of DIP 2.
Two principal applications Processing of image data for a) Storage b) Transmission E.g. Image Coding (assume both of the following images have the same file size)
silvanti.com
Main Applications of DIP Two principal applications 2. Processing of image data for c) Autonomous machine perception E.g. Optical Character Recognition (OCR)
DIP – Bernd Girot
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DIP Levels
DIP – Dr. Arıöz
Components of a DIP System
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Selected Applications
The Hubble Telescope Incorrect mirror selection distorted images significantly Image processing methods used to fix images
DIP – Dr. Arıöz
Selected Applications
Pseudo/False Color
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Selected Applications
Noise Reduction
DIP – Dr. Arıöz
Selected Applications
Image Enhancement
DIP – Dr. Arıöz
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Selected Applications
Image Restoration
DIP – Dr. Arıöz
Selected Applications
Image Segmentation
mathworks.com
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What we have talked about DIP
is only the visible part of an iceberg...
Questions
? 60
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