1. January 2004 Chuck DiMarzio, Northeastern University 10471-3-1 ECEU692 Subsurface Imaging Course Notes Part 3: Imaging with Light (2) Hyperspectral Imaging Profs. Brooks and DiMarzio Northeastern University Spring 2004

2. January 2004 Chuck DiMarzio, Northeastern University 10471-3-2 Hyperspectral Imaging Concepts Absorption Spectroscopy Scattering Reflectance Spectroscopy Imaging Hyperspectral Imaging The Data Cube ER-2 AVIRIS

3. January 2004 Chuck DiMarzio, Northeastern University 10471-3-3 Beer’s Law

4. January 2004 Chuck DiMarzio, Northeastern University 10471-3-4 Sample Absorption Spectra Data from Van Assendelft, O. W., Spectrophotometry of Haemoglobin Derivatives, Springfield, IL: Thomas, 1970. Graph by DiMarzio, Warner, Dwyer, Northeastern University, 1994 686 Hb HbO 2  a Specific Absorption, /cm /M, Wavelength, nm

5. January 2004 Chuck DiMarzio, Northeastern University 10471-3-5 Light in a Turbid Medium Specular Components –Fresnel Coefficients –Beer’s Law Diffuse Components –More Complicated Some Examples –Paint –Clouds

6. January 2004 Chuck DiMarzio, Northeastern University 10471-3-6 Reflectance Spectroscopy; Weak Scattering

7. January 2004 Chuck DiMarzio, Northeastern University 10471-3-7 A Simple Model  a ( 1 )=C 1  1 ( 1 )+ C 2  2 ( 1 )  a ( 2 )=C 1  1 ( 2 )+ C 2  2 ( 2 ) Two Measurements, Two Equations, and Two Unknowns Later, Prof. Brooks will talk about inverting these equations

8. January 2004 Chuck DiMarzio, Northeastern University 10471-3-8 Reflectance Spectroscopy; Strong Scattering

9. January 2004 Chuck DiMarzio, Northeastern University 10471-3-9 Pulse Oximeter 2 LED’s –Different IR Wavelengths DC Components –Total Hb, HbO 2, Other Absorbers Pulsatile Component –Arterial Hb, HbO 2

10. January 2004 Chuck DiMarzio, Northeastern University 10471-3-10 Hyperspectral Imaging Overview Definition (Multi-, Hyper, Ultra-Spectral) The Data Cube Image Acquisition Hardware, Data Visualization HOSIS - Hyperspectral Oxygen Saturation Imaging System: –CCD –Lyot Filter –Digital Imaging

11. January 2004 Chuck DiMarzio, Northeastern University 10471-3-11 Hyperspectral Imaging Definitions? –Imaging in multiple bands with width less than (10%?) of the center frequency –Imaging in more than (25?) bands –Imaging in Contiguous Bands x y The Hyperspectral “Data Cube”

12. January 2004 Chuck DiMarzio, Northeastern University 10471-3-12 Hyperspectral Imaging Hardware Concepts (1) Camera Coordinates are Spatial Successive Images are Different Wavelengths Tunable Filter B/W Camera x y

13. January 2004 Chuck DiMarzio, Northeastern University 10471-3-13 Hyperspectral Imaging Hardware Concepts (2) Pushbroom Scan –Airborne or Vehicle Mounted? –Camera Coordinates are y, –Successive Scans are Different values of x x y

14. January 2004 Chuck DiMarzio, Northeastern University 10471-3-14 HOSIS Instrumentation Block Diagram Computer System with Video Board Processed Images Tunable Filter See Supplementary Notes CCD Camera Halogen Lamp Target Tissue Thanks to Peter Dwyer at Lucid Technologies, MGH, and NU

15. January 2004 Chuck DiMarzio, Northeastern University 10471-3-15 Quantitative Imaging Quantitative Calculations –Difficult –Subject to Change Calibration Standards –Light Level –Reflectance Sources of Variation –Light Source –Camera Sensitivity –Filter Losses –Geometry –Atmosphere? –Other?