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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