ECEU692 Subsurface Imaging Course Notes Part 2: Imaging with Light (1)

1. ECEU692Subsurface ImagingCourse NotesPart 2: Imaging with Light (1) Profs. Brooks and DiMarzio Northeastern University Spring 2004 Chuck DiMarzio, Northeastern University

2. Lecture Overview • Optical Spectrum and Sources • Interaction of Light with Matter • A Bit of Geometric Optics • A Bit of Physical Optics • Microscopes (1) • Point-Spread Function • Optical Transfer Function • Detectors and Cameras Chuck DiMarzio, Northeastern University

3. Classical Maxwellian EM Waves Thanks to Prof. S. W.McKnight v=c λ E H H x E E z H λ=c/υ y c=3x108 m/s (free space) υ = frequency (Hz) Chuck DiMarzio, Northeastern University

4. VIS= 0.40-0.75μ γ-Ray RF Electromagnetic Spectrum (by λ) UV= Near-UV: 0.3-.4 μ Vacuum-UV: 100-300 nm Extreme-UV: 1-100 nm IR= Near: 0.75-2.5μ Mid: 2.5-30μ Far: 30-1000μ 10 nm =100Å 0.1 μ 1 μ 10 μ 100 μ = 0.1mm (300 THz) 0.1 Å 1 Å 10 Å 1 mm 1 cm 0.1 m X-Ray Soft X-Ray Mm-waves Microwaves Chuck DiMarzio, Northeastern University Thanks to Prof. S. W.McKnight

5. 6000K Sun 6.9 G Lux Visible Sunlit Cloud 6.9 k Lux Near IR Mid IR Blue Sky 300K night sky Far IR Typical Outdoor Radiance Levels Ultraviolet Atmospheric Passbands Chuck DiMarzio, Northeastern University

6. T = 300 K 1 /Delta T 0.5 l M D 0 -1 0 1 2 10 10 10 10 T = 500 K 6 /Delta T 4 l 2 M D 0 -1 0 1 2 10 10 10 10 l m , Wavelength, m Thermal Imaging Chuck DiMarzio, Northeastern University

7. Specular Diffuse Reflection Reflection Light in a Turbid Medium Input Scattering Absorption Direct Transmission Diffuse Transmission Chuck DiMarzio, Northeastern University

8. Slab Absorption Slab Absorption and Scattering Semi-Infinite Medium Two-Layer Example Interactions Chuck DiMarzio, Northeastern University

9. Lecture Overview • Optical Spectrum and Sources • Interaction of Light with Matter • A Bit of Geometric Optics • A Bit of Physical Optics • Microscopes (1) • Point-Spread Function • Optical Transfer Function • Detectors and Cameras Chuck DiMarzio, Northeastern University

10. f s f’ s’ Camera Lens Image Location A F’ A’ F Lens Equation Chuck DiMarzio, Northeastern University

11. s s’ Camera Lens Magnification x A -x’ A’ Chuck DiMarzio, Northeastern University

12. Field of View Film= Exit Window Chuck DiMarzio, Northeastern University

13. Diffraction x1 x What is the light distribution in the spot? Chuck DiMarzio, Northeastern University

14. Fraunhofer Diffraction Chuck DiMarzio, Northeastern University

15. R d0 Point Spreadand Optical Transfer Functions Fourier Transform object OBJECT x’ scale SCALE perfect image PERFECT IMAGE x’ x MULT OTF Convolve with PSF actual image ACTUAL IMAGE Chuck DiMarzio, Northeastern University

16. Fraunhoffer Examples Chuck DiMarzio, Northeastern University

17. Coherent and Incoherent OTF • Incoherent Image • Irradiance rather than field. • PSFinc is |PSFcoh|2 • Fourier Transform • OTFinc is |OTFcoh|2 • Meaning of Phase is a bit complicated Chuck DiMarzio, Northeastern University

18. 1 0.9 20 0.8 40 0.7 60 0.6 80 20 0.5 100 40 0.4 20 120 60 0.3 40 140 80 0.2 60 160 0.1 100 80 180 0 120 20 40 60 80 100 120 140 160 180 100 140 120 160 140 180 20 40 60 80 100 120 140 160 180 160 180 20 40 60 80 100 120 140 160 180 An Extreme Example Colorbar for all Object Image Point-Spread Function of System Chuck DiMarzio, Northeastern University

19. f s s’ Bright-Field Microscopy F A’ A F’ f’ Object Plane Image Plane Chuck DiMarzio, Northeastern University

20. Lecture Overview • Optical Spectrum and Sources • Interaction of Light with Matter • A Bit of Geometric Optics • A Bit of Physical Optics • Microscopes (1) • Point-Spread Function • Optical Transfer Function • Detectors and Cameras Chuck DiMarzio, Northeastern University

21. Semiconductor Detector Conduction Band Absorption Emission 10057p1-2 here Valence Band hn e- Chuck DiMarzio, Northeastern University

22. S, Source G, Gate D, Drain n+ n+ SiO2 Insulator 20-100mm Channel: 2 to 500 mm into page P-Type Material NMOS B, Body Remember N-FET Structure? Metal-Oxide-Semiconductor Channel Length 1 to 10 mm Chuck DiMarzio, Northeastern University

23. Charge-Coupled Device (CCD) G S S D D B B ~10 mm X nRows Channel Length 1 to 10 mm Chuck DiMarzio, Northeastern University

24. Clock Voltage 1 0.9 2 0.8 4 0.7 0.6 m10057_1.m Figure 1 6 Row Number 0.5 0.4 8 0.3 10 0.2 0.1 12 0 0 0.5 1 1.5 2 2.5 3 time, Clock Cycles CCD Charge Transfer V One Line V Clock Signals time Chuck DiMarzio, Northeastern University

25. Computer Interfacing • Analog Camera and Frame Grabber • Digital Camera Digital Camera Analog Camera Computer Computer with Frame Grabber Computer Monitor Analog Monitor Computer Monitor Chuck DiMarzio, Northeastern University

26. 1 0.8 0.6 Output Voltage 0.4 0.2 0 0 0.2 0.4 0.6 0.8 1 Input Voltage Linearity and AGC • Automatic Gain Control (AGC) • Feedback • Control G • Based on... • Peak Signal • Average Signal • Peak in a Region • Not Desirable for Quantitative Work Chuck DiMarzio, Northeastern University

27. Pixelation and Digitization Count 255 0 “Brightness” Chuck DiMarzio, Northeastern University

28. Digitization and Dynamic Range 2N-1 Saturation Maximum Signal Minimum Signal Step Size Pedestal Signal Voltage 0 Dark Chuck DiMarzio, Northeastern University

29. Some Standard and Extreme Parameters • VGA Frame Size: 640 by 480 • Up to 4k Square? • Standard Update Rate: 30 Hz. Interlaced • Up To few kHz. • Standard Digitization: 8 Bits • Up To 12. • Pixel Size: 10 micrometers. • Color Camera: 3 Channels, 8 Bits Each Chuck DiMarzio, Northeastern University