Computer Imaging Systems Sobia Tariq Javed Computer Imaging

Computer Imaging Systems Sobia Tariq Javed

Computer Imaging Systems � Consists of two primary components: � Hardware � -Image acquisition system, computer, and display devices � Software �– Image manipulation, analysis, and processing

Computer Imaging Systems Hardware Image manipulation, analysis, and processing

Analog Camera Signal

Digitization: Transformation of video signal into digital image

� Image is accessed as a 2 -D array of data, where each data point is referred to as a pixel � Notation: � I(r, c) = Brightness of image at the pt (r, c) � where r = row, and c = column

Hierarchical image pyramid: Consists of levels for processing of images

Image receives reflections s refle ct ht Lig es h c ea s y Energ e Sourc ce a f r u r Se ns Surf aces or ele me nt rec eiv es ligh te Intensity matters Angles matter Material maters ne rgy

Sensors � A) Electromagnetic Spectrum (EM) � B) Acoustical (sound) energy � C) Electron beams � D) Lasers

Electromagnetic Spectrum 1 5 3 4 2 6 7

1) Imaging with Gamma-Rays Imaging with gamma-rays is done by measuring the rays as they are emitted from the object. In Nuclear medicine using Positron emission tomography (PET), a patient is injected with a radioactive isotope and as it decays gamma rays are detected and measured.

PET studies of glucose metabolism to map human brain's response in performing different tasks. Subjects looking at a visual scene activated visual cortex (arrow), listening to a mystery story with language and music activated left and right auditory cortices (arrows), counting backwards from 100 by sevens activated frontal cortex (arrows), recalling previously learned objects activated hippocampus bilaterally (arrows), and touching thumb to fingers of right hand activated left motor cortex and supplementary motor system (arrows).

2) Imaging with X-Rays X-rays are used in medical diagnostics by using film that responds to x-ray energy which is placed between the energy source and the patient.

2) Imaging with X-Rays X-ray of a chest with an implanted electronic device to assist the heart Dental x-ray

Computerized Tomography

Computerized Tomography One “slice” of a CT image of a patient’s abdomen, multiple 2 -D image “slices” are taken at various angles and are then assembled to create a 3 -D image

3) Ultraviolet Imaging Applications: 1) Law enforcement [forensics] 2) Microscopy 3) Astronomy

Fluorescence Microscopy Images of cell

4) Visible Light Imaging

5) Infrared Imaging

Thermal Imaging

Infrared Satellite Image showing water vapor

Multispectral Images � NASA_SDO_multispectral_view_of_the_Sun

6) Microwave Imaging

Microwave Imaging

7) Radio Wave Imaging Magnetic Resonance Image (MRI) of a shoulder

B) Acoustic Imaging Application: 1) Mineral & Oil Exploration 2) Medicines 3) Sonar system in submarines

C) Electron Imaging Scanning Electron Microscope (SEM) SEM Image of a mosquito

Electron Imaging SEM image of Strawberry SEM Image of logic gate in a microchip

D) Laser Imaging LASER : Light amplification by Stimulated Emission of Radia

Computer Generated Images