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ECEU692
Subsurface Imaging
Course Notes
Part 14: A Pause to Reflect
Profs. Brooks and DiMarzio
Northeastern University
Spring 2004
March 2004
Chuck DiMarzio, Northeastern University
10471-14-1
From Our First Lecture...
•
•
•
•
Some Examples
Some Technologies
NSF Center; CenSSIS at NU
Taxonomies and Architectures of the Field
March 2004
Chuck DiMarzio, Northeastern University
10471-14-2
Some SSI Examples
•
•
•
•
•
•
•
•
•
•
•
•
Landmine Detection [Acoustic, GPR, EM, NQR]
Tunnel and Bunker Detection [Acoustic, GPR, EM]
Excavation Planning [Acoustic, GPR, EM]
Luggage Screening [X-Ray, NQR]
Ocean Imaging [HSI]
Breast Tumor Detection and Classif.[X-Ray, US, DOT]
Stroke Differentiation [DOT, MRI]
Functional Brain Imaging [DOT, MRI]
Cardiac Imaging [Ultrasound, EKG]
Retinal Imaging [HSI, Vis]
Vulnerable Plaque in Coronary Artery [Vis, US, OCT]
Fetal Imaging [DOT, Ultrasound]
March 2004
Chuck DiMarzio, Northeastern University
10471-14-3
Model Subsurface Problems
• Problem Geometry
– A* Looking through one material to see another
which is below it.
– B* Looking through one material to find
inhomogeneities in it.
• Application Areas
– 1* Air/Space, 2* Terrestrial, 3* Ocean,
4* Medical, 5* Biological
* Letters and Numbers Refer to Next Slide
March 2004
Chuck DiMarzio, Northeastern University
10471-14-4
Model Subsurface Problems
1 Air/Space
Landuse
2 Terestrial
Excavation
Planning
3 Ocean
4 Medical
Seabed
Mapping
Dermatology
5 Biological
ICM Cell
Counting
CORAL
REEFS
A
Atmospheric
Gasses
Landmine
Detection
Pollution
Mapping
Mapping
Functional
Brain Mapping Mitochondria
River
Plume
B
March 2004
Chuck DiMarzio, Northeastern University
10471-14-5
Example Problems for the Course
• Geometries
– Semi-Infinite Slab Lab in HW2
– Two-Layers HW3
– Embedded Object Lab in HW4
• SSI Technology
– Hyperspectral Imaging Lab in HW2
• Coursework
– Experiments
– Analysis
March 2004
Chuck DiMarzio, Northeastern University
10471-14-6
Some SSI Technologies
•
•
•
•
•
•
•
•
•
•
X-Ray
Light (UV, Visible, Infrared)
Ground-Penetrating Radar
Electrical Impedance Tomography
Magnetic Resonance Imaging
Acoustics and Ultrasound
Electromagnetic Sensors
Passive Electromagnetic Imaging
Seismics
Others
March 2004
Chuck DiMarzio, Northeastern University
~Wavelength
10471-14-7
Different Types of Waves
8
10
6
k/(2p), Wavenumber, m -1
10
Light
(Real)
mm
1mm
4
10
mm
Sound
2
10 cm
0
(Imag)
1mm
(Imag)
1m
(Real)
m
10
DPDW
-2
10
1km
km
-4
10 0
10
March 2004
10059_1
5
10
10
10
f, Frequency, Hz.
15
10
Chuck DiMarzio, Northeastern University
20
10
10471-14-8
Wave Behavior
•
•
•
•
•
•
Absorption
Reflection
Refraction
Diffraction
Interference
Scattering
10471-15-1.jpg
Thanks to Emmanuel Bossy, BU
Remember HW 1?
March 2004
Chuck DiMarzio, Northeastern University
10471-14-9
Light in Skin and More
Optical Imaging
Stratum
Corneum,
5-10mm
Vis
Diffusive Imaging
NIR
Vis NIR
keratinocytes
Epidermis,
50-100mm
Dermis,
few mm
March 2004
Basal cell
cancer
(RCM)
melanocytes
collagen and
elastin
Chuck DiMarzio, Northeastern University
10471-14-10
1. Definition & Scope of SSI
Probe(s) 1 2 .. I
1 2 .. J Detector(s)
One or more probes
Detector
Probe
transmit one or more waves,
system
system
which are launched into the
medium after processing by
some probe system.
Medium
The waves are characterized
object
by their location, power,
frequency, waveform,
Medium & object are characterized
polarization, etc
One or more detectors
characterized by their
location, sensitivity,
or noise, detect the
waves after processing
by some detector
system
by physical properties,
to which the probe waves are sensitive.
Thanks to Prof. Bahaa Saleh, Chair of ECE at Boston
University for the concept for this and following slides.
March 2004
Chuck DiMarzio, Northeastern University
10471-14-11
Examples of wave-dependent
properties
Electromagnetic
• Dielectric constant
• Conductivity
• Nuclear spin
Electrical/Magnetic
• Conductivity
• Permeability
March 2004
Optical
• Refractive index
• Absorption coeff.
• Fluorescence
Acoustic
• Density
• Compressibility
Chuck DiMarzio, Northeastern University
Thanks to Prof. Bahaa Saleh
X-Ray
• Absorption
Particle Beams
Electron,Positron,..
• Scattering
• Emission of x-ray or
• secondary emission
10471-14-12
Goals of SSI
Examples of
Underlying
Parameters
• Estimate
– Distribution of Measured
Parameters or
– Underlying Parameters
Related to Them, or
– Object Shape or Features or
• Detect the Presence of a
Target or
• Classify Objects Based on
Measured Parameters
March 2004
 Density, Porosity, Stiffness
 Chemical composition, pH
 Metabolic information
 Ion concentration
 Physiological changes (e.g.,
oxygenation)
 Extrinsic markers (dyes,
chemical tags)
Chuck DiMarzio, Northeastern University
Thanks to Prof. Bahaa Saleh
10471-14-13
Probes
Detectors
Surface
Taxonomy of SSI
.
Medium
object
Electro- Optical/
Acoustic X-ray
magnetic
IR
CW
Pulsed Modulated
Absorption
Partially
MultiCoherent Spectral
Quantum
Classical
Outside
Inside
March 2004
Auxiliary
Absorption Fluorescence
Nonlinear
Absorption
Dispersion
Scattering
Coherent
Object
Medium
Probe
Nonlinear
Scattering Scattering
Diffusion
Clutter
Inhomogeneous/
Layered
Rough Surface
Chuck DiMarzio, Northeastern University
Thanks to Prof. Bahaa Saleh
Diffusive
Phase
Object
Depolarizing
Stationary Moving
10471-14-14
Architectures of SSI
Transmitter
(Probe) & Receiver (detector) Patterns
i
j
i
Probe Pattern:
Region in the medium occupied by
the probe wave, in the absence of the
target & clutter
March 2004
j
Detector Pattern:
Region in the medium to which the
detector is sensitive, I.e., , if a source
were to exist within this medium, it
would be detected.
Chuck DiMarzio, Northeastern University
Thanks to Prof. Bahaa Saleh
10471-14-15
Localized vs Tomographic SSI
Localized SSI
1 2 .. I
Probe
System
Tomograhic SSI
LP
1 2 .. J
1 2 .. I
1 2 .. J
Detector
System
Probe
System
Detector
System
j
i
j
i
ij
MVT
ij
Interaction regions {ij} are small &
do not overlap significantly
Interaction regions {ij} are large &
do overlap significantly
Interaction region Vij = region in the medium to which the
signal of detector j is sensitive, when probe wave i is active
March 2004
Chuck DiMarzio, Northeastern University
Thanks to Prof. Bahaa Saleh
10471-14-16
Example i) Distributed Probe/
Localized Detection
LP
Transverse Scanning
Axial Scanning
Transverse Gazing
Axial Scanning
Example: Photography
March 2004
Chuck DiMarzio, Northeastern University
Thanks to Prof. Bahaa Saleh
10471-14-17
Example ii) Localized probe/
distributed (bucket) detection
LP
Two-Photon Scanning
Laser Microscopy
Good transverse resolution
Poor axial resolution
March 2004
Chuck DiMarzio, Northeastern University
Thanks to Prof. Bahaa Saleh
10471-14-18
Example iii) Confocal probe and
detection
LP
Both axial & transverse resolution
March 2004
Chuck DiMarzio, Northeastern University
Thanks to Prof. Bahaa Saleh
10471-14-19
Example iv) Pulsed Coaxial
probe and detection
LP
Transverse resolution by scanning
Axial resolution by time of flight sectioning
March 2004
Chuck DiMarzio, Northeastern University
Thanks to Prof. Bahaa Saleh
10471-14-20
Example v) Axial Tomography
MVT
Computed transverse & axial resolution
March 2004
Chuck DiMarzio, Northeastern University
Thanks to Prof. Bahaa Saleh
10471-14-21
Example vi) Diffusive Photon
Density Waves
Transmission
Reflection
Generally poor axial and transverse resolution
March 2004
Chuck DiMarzio, Northeastern University
Thanks to Prof. Bahaa Saleh
10471-14-22
Example vii) Time-Domain
Photon Migration
Transmission
Reflection
Generally poor axial and transverse resolution
March 2004
Chuck DiMarzio, Northeastern University
10471-14-23
Why Did We Choose What We
Did?
• It’s at least somewhat representative of the
scope of SSI
• We know it well
• It allows you to explore problems in depth
• It allows you to do some experiments in our
labs
March 2004
Chuck DiMarzio, Northeastern University
10471-14-24
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