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

January 2004 Chuck DiMarzio, Northeastern University 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

January 2004 Chuck DiMarzio, Northeastern University 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

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

January 2004 Chuck DiMarzio, Northeastern University Typical Outdoor Radiance Levels Visible Near IR Mid IR Far IR Atmospheric Passbands Ultraviolet

January 2004 Chuck DiMarzio, Northeastern University Thermal Imaging  M /Delta T T = 300 K , Wavelength,  m  M /Delta T T = 500 K

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

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

January 2004 Chuck DiMarzio, Northeastern University 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

January 2004 Chuck DiMarzio, Northeastern University Camera Lens Image Location F’ F A’ A Lens Equation ff’ ss’

January 2004 Chuck DiMarzio, Northeastern University Camera Lens Magnification A’ A ss’ x -x’

January 2004 Chuck DiMarzio, Northeastern University Field of View Film= Exit Window

January 2004 Chuck DiMarzio, Northeastern University Diffraction x1x1 x What is the light distribution in the spot?

January 2004 Chuck DiMarzio, Northeastern University Fraunhofer Diffraction

January 2004 Chuck DiMarzio, Northeastern University 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

January 2004 Chuck DiMarzio, Northeastern University Fraunhoffer Examples

January 2004 Chuck DiMarzio, Northeastern University 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

January 2004 Chuck DiMarzio, Northeastern University An Extreme Example Object Point-Spread Function of System Image Colorbar for all

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

January 2004 Chuck DiMarzio, Northeastern University 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

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

January 2004 Chuck DiMarzio, Northeastern University 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  m Channel: 2 to 500  m into page NMOS Metal-Oxide-Semiconductor

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

January 2004 Chuck DiMarzio, Northeastern University CCD Charge Transfer Clock Signals time One Line V V

January 2004 Chuck DiMarzio, Northeastern University Computer Interfacing Analog Camera and Frame Grabber Digital Camera Analog Camera Computer with Frame Grabber Analog Monitor Computer Monitor Digital Camera Computer Monitor

January 2004 Chuck DiMarzio, Northeastern University Linearity and AGC 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

January 2004 Chuck DiMarzio, Northeastern University Pixelation and Digitization “Brightness” Count 0 255

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

January 2004 Chuck DiMarzio, Northeastern University 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