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Innovative Distance Detection Techniques for Consumer Optoelectronics

Explore the fascinating world of distance detection using optoelectronics in various applications, from commercial to military, through laser sources and interferometric techniques. Discover the endless possibilities for future development and research.

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Innovative Distance Detection Techniques for Consumer Optoelectronics

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  1. DISTANCE DETECTION EE 594 - Consumer Optoelectronics Dave Vu March 17, 1999

  2. MOTIVATION • My Motives • Concept is simple • Why others may be interested • Distance/Velocity measurement is an essential tool in many commercial and military applications • Endless possibilities for future development and research

  3. OVERVIEW • Many ways to detect distances using wave propagation properties • visible light ( 380 - 770 nm) • infrared ( > 800 nm) • microwaves ( > 4000nm) • Best Detection Method depends on Level of Detection desired • Application Specific: Range of distance desired? Error allowed? Coherent Signals? Pros/Cons? Laser Sources

  4. BASIC CONCEPT • Emitter: Direct a beam at approaching or receding object • Receiver: Portion of beam is reflected and received by Detection Unit • Translation of Signal • Point Light Source: Flux Dens  1/distance2 • Lasers: Time dependent using ‘c’ as reference; Distance = RT / 2 • Interferometry: Phase Difference  Distance • Microwaves:  Frequency  velocity

  5. POINT SOURCE Flux Density = I / d2

  6. POINT SOURCE ERROR

  7. INTERFEROMETRY • Used for very • small distances • Coherency: • same wavelength • and phase • Phase Difference • and Position • Other Applications: • Stress/Stain Analysis

  8. MOIRE EFFECT • Mechanical Interference of light by superimposed network of lines Incident Light Specimen Grating (object) Master Grating (reference) N=0 N=1 Actual Transmitted Light N=1/2 X = N * p ; where N = Order p = pitch of master

  9. Radar Microwaves Supported by the Doppler Effect:  Frequency  velocity beam of microwave energy (~9000-28000nm) hits target and a portion of it is reflected reflected beam is shifted in frequency proportional to velocity of target => Signal Processing Scatterability Lasers Similar concept as radar except: Coherent light source sample of change in distance over a period of time Accuracy of reading are affected by: halogen lamps,weather,reflection and refraction of beam SPEED DETECTION

  10. APPLICATIONS • Commercial • Vehicles, Speed Regulation • Personal use: Room Dimensions • Maufacturing, Robotics • Military • Positioning / Locating applications • Education/Research • NASA/NSF: Shuttle missions, measurement of distance in other mediums (ie. atmospheres, space)

  11. SUMMARY • General concept with lots of potential • Many ways of interpreting and manipulating signals • The method we use to analyze it relies heavily on the requirements of the application

  12. REFERENCES • General Laser Reference Sites • http://www.fastguy.com/ • http://www.intl-light.com/handbook • Laser measurement • http://www.renishaw.com/laserscale/ • Position Determination Using Lasers • http://on-trak.com/psd • Laser Range Finders (LIDAR) • http://www.meos.com/_Pages/EXP15-ENG-NAV.htm • http://ranier.oact.hq.nasa.gov/Sensors_page/Laser/LaserOV.html • http://www.ksc.nasa.gov/shuttle/missions/sts-64/mission-sts-64.html • Distance Detection Using Interferometric Techniques • http://web.wse.nadn.navy.mil/wse/academic/courses/es300/supplem/interfer.htm

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