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

2. January 2004 Chuck DiMarzio, Northeastern University 10471-2-2 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

3. January 2004 Chuck DiMarzio, Northeastern University 10471-2-3 Classical Maxwellian EM Waves E E E x y z H H H λ v=c λ=c/υ c=3x10 8 m/s (free space) υ = frequency (Hz) Thanks to Prof. S. W.McKnight

4. January 2004 Chuck DiMarzio, Northeastern University 10471-2-4 Electromagnetic Spectrum (by λ) 1 μ10 μ100 μ = 0.1mm 0.1 μ10 nm =100Å VIS= 0.40-0.75μ 1 mm1 cm0.1 m IR= Near: 0.75-2.5μ Mid: 2.5-30μ Far: 30-1000μ UV= Near-UV: 0.3-.4 μ Vacuum-UV: 100-300 nm Extreme-UV: 1-100 nm MicrowavesX-RayMm-waves 10 Å1 Å0.1 Å Soft X-RayRFγ-Ray (300 THz) Thanks to Prof. S. W.McKnight

5. January 2004 Chuck DiMarzio, Northeastern University 10471-2-5 Typical Outdoor Radiance Levels Visible Near IR Mid IR Far IR Atmospheric Passbands Ultraviolet

6. January 2004 Chuck DiMarzio, Northeastern University 10471-2-6 Thermal Imaging  M /Delta T 10 10 0 1 2 0 0.5 1 T = 300 K 10 10 0 1 2 0 2 4 6, Wavelength,  m  M /Delta T T = 500 K

7. January 2004 Chuck DiMarzio, Northeastern University 10471-2-7 Input Diffuse Reflection Absorption Diffuse Transmission Scattering Specular Reflection Direct Transmission Light in a Turbid Medium

8. January 2004 Chuck DiMarzio, Northeastern University 10471-2-8 Example Interactions Slab Absorption Two-Layer Slab Absorption and Scattering Semi-Infinite Medium

9. January 2004 Chuck DiMarzio, Northeastern University 10471-2-9 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

10. January 2004 Chuck DiMarzio, Northeastern University 10471-2-10 Camera Lens Image Location F’ F A’ A Lens Equation ff’ ss’

11. January 2004 Chuck DiMarzio, Northeastern University 10471-2-11 Camera Lens Magnification A’ A ss’ x -x’

12. January 2004 Chuck DiMarzio, Northeastern University 10471-2-12 Field of View Film= Exit Window

13. January 2004 Chuck DiMarzio, Northeastern University 10471-2-13 Diffraction x1x1 x What is the light distribution in the spot?

14. January 2004 Chuck DiMarzio, Northeastern University 10471-2-14 Fraunhofer Diffraction

15. January 2004 Chuck DiMarzio, Northeastern University 10471-2-15 Point Spreadand Optical Transfer Functions x’ x R d0d0 object perfect image actual image scale Convolve with PSF Fourier Transform OBJECT PERFECT IMAGE ACTUAL IMAGE SCALE MULT OTF

16. January 2004 Chuck DiMarzio, Northeastern University 10471-2-16 Fraunhoffer Examples

17. January 2004 Chuck DiMarzio, Northeastern University 10471-2-17 Coherent and Incoherent OTF Incoherent Image –Irradiance rather than field. –PSF inc is |PSF coh | 2 Fourier Transform –OTF inc is |OTF coh | 2 –Meaning of Phase is a bit complicated

18. January 2004 Chuck DiMarzio, Northeastern University 10471-2-18 An Extreme Example 20406080100120140160180 20 40 60 80 100 120 140 160 180 20406080100120140160180 20 40 60 80 100 120 140 160 180 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 20406080100120140160180 20 40 60 80 100 120 140 160 180 Object Point-Spread Function of System Image Colorbar for all

19. January 2004 Chuck DiMarzio, Northeastern University 10471-2-19 Bright-Field Microscopy F F’ A A’ f’f s’s Image Plane Object Plane

20. January 2004 Chuck DiMarzio, Northeastern University 10471-2-20 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

21. January 2004 Chuck DiMarzio, Northeastern University 10471-2-21 Semiconductor Detector Valence Band Conduction Band h e-e- EmissionAbsorption 10057p1-2 here

22. January 2004 Chuck DiMarzio, Northeastern University 10471-2-22 Remember N-FET Structure? Channel Length 1 to 10  m B, Body n+n+ n+n+ S, SourceG, GateD, Drain P-Type Material SiO 2 Insulator 20-100  m Channel: 2 to 500  m into page NMOS Metal-Oxide-Semiconductor

23. January 2004 Chuck DiMarzio, Northeastern University 10471-2-23 Charge-Coupled Device (CCD) Channel Length 1 to 10  m B S G D S D B ~10  m X n Rows

24. January 2004 Chuck DiMarzio, Northeastern University 10471-2-24 CCD Charge Transfer Clock Signals time One Line V V

25. January 2004 Chuck DiMarzio, Northeastern University 10471-2-25 Computer Interfacing Analog Camera and Frame Grabber Digital Camera Analog Camera Computer with Frame Grabber Analog Monitor Computer Monitor Digital Camera Computer Monitor

26. January 2004 Chuck DiMarzio, Northeastern University 10471-2-26 Linearity and AGC 00.20.40.60.81 0 0.2 0.4 0.6 0.8 1 Input Voltage Output Voltage Automatic Gain Control (AGC) Feedback –Control G –Based on... Peak Signal Average Signal Peak in a Region Not Desirable for Quantitative Work

27. January 2004 Chuck DiMarzio, Northeastern University 10471-2-27 Pixelation and Digitization “Brightness” Count 0 255

28. January 2004 Chuck DiMarzio, Northeastern University 10471-2-28 Digitization and Dynamic Range Signal Voltage 2 N -1 0 Pedestal Saturation Step Size Dark Minimum Signal Maximum Signal

29. January 2004 Chuck DiMarzio, Northeastern University 10471-2-29 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