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CHAPTER 5

PRE-PROCESSING. CHAPTER 5. Atmospheric Influence and Radiometric Correction. A. Dermanis. Atmospheric Influence. Ideal situation: - sun and sensor above observed pixel, - flat terrain, - no atmosphere. A. Dermanis. Atmospheric Influence. Ideal situation: - sun and sensor

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CHAPTER 5

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  1. PRE-PROCESSING CHAPTER 5 Atmospheric Influence and Radiometric Correction A. Dermanis

  2. Atmospheric Influence Ideal situation: - sun and sensor above observed pixel, - flat terrain, - no atmosphere. A. Dermanis

  3. Atmospheric Influence Ideal situation: - sun and sensor above observed pixel, - flat terrain, - no atmosphere. E0= incident irradiance Er= reflected irradiance ρ= reflectivity (caracterizes pixel class) L0= illuminance (recorded at sensor) A. Dermanis

  4. Atmospheric Influence Ideal situation: - sun and sensor above observed pixel, - flat terrain, - no atmosphere. E0= incident irradiance Er= reflected irradiance ρ= reflectivity (caracterizes pixel class) L0= illuminance (recorded at sensor) π = solid angle of upper half space where Er is diffused A. Dermanis

  5. Atmospheric Influence Influence of atmosphere: - Incident irradiance E0 reduced by a factor T0, - reflected illuminance L0 reduced by a factor T0. A. Dermanis

  6. Atmospheric Influence Influence of atmosphere: - Incident irradiance E0 reduced by a factor T0, - reflected illuminance L0 reduced by a factor T0. LS= illuminance (recorded at sensor) A. Dermanis

  7. Atmospheric Influence - sun at zenith angle θ over observed pixel, - sensor at zenith angle  over observed pixel. A. Dermanis

  8. Atmospheric Influence - sun at zenith angle θ over observed pixel, - sensor at zenith angle  over observed pixel. E= incident irradiance reduced by a factor Tθ > Τ0 (passing thicker layer) and by a factor cosθ (spread over larger area) LT= illuminance (recorded at sensor) reduced by a factor T > T0 A. Dermanis

  9. Atmospheric Influence - sun at zenith angle θ over observed pixel, - sensor at zenith angle  over observed pixel. E= incident irradiance reduced by a factor Tθ > Τ0 (passing thicker layer) and by a factor cosθ (spread over larger area) LT= illuminance (recorded at sensor) reduced by a factor T > T0 A. Dermanis

  10. Atmospheric Influence - sun at zenith angle θ over observed pixel, - sensor at zenith angle  over observed pixel. E= incident irradiance reduced by a factor Tθ > Τ0 (passing thicker layer) and by a factor cosθ (spread over larger area) LT= illuminance (recorded at sensor) reduced by a factor T > T0 A. Dermanis

  11. Atmospheric Influence Additional incident irradiance ED diffused from atmosphere (origin: sun and other earth pixels) A. Dermanis

  12. Atmospheric Influence Additional incident irradiance ED diffused from atmosphere (origin: sun and other earth pixels) EG= incident irradiance LT= illuminance (recorded at sensor) A. Dermanis

  13. Atmospheric Influence Additional illuminance LP diffused from atmosphere (origin: sun and other earth pixels) A. Dermanis

  14. Atmospheric Influence Additional illuminance LP diffused from atmosphere (origin: sun and other earth pixels) LS= illuminance (recorded at sensor) A. Dermanis

  15. Atmospheric Influence Final situation: E0 = incident irradiance from sun Tθ = atmospheric absorbance on incident irradiance cosθ =reduction factor for pixel inclined to incident radiation ED = irradiance diffused from atmosphere ρ = pixel reflectance π = solid angle of upper half space Tφ =atmospheric absorbance on reflected illuminance LP = illuminance diffused from atmosphere A. Dermanis

  16. Radiometric Corection illuminance arriving at sensor: A. Dermanis

  17. Radiometric Corection illuminance arriving at sensor: instead of ideal: a = atmospheric condition parameters A. Dermanis

  18. Radiometric Corection illuminance arriving at sensor: instead of ideal: a = atmospheric condition parameters recorded at sensor: k0, C0 = nominal sensor parameters instead of ideal: A. Dermanis

  19. Radiometric Corection illuminance arriving at sensor: instead of ideal: a = atmospheric condition parameters recorded at sensor: k0, C0 = nominal sensor parameters instead of ideal: Radiometric correction: Recovery of x0 from x A. Dermanis

  20. Radiometric Correction (a) Sensor Calibration: Computation of k and C (b) Radiometric correction for sensor instability (c) Determination of atmospheric influence parameters (d) Radiometric correction for atmospheric influence A. Dermanis

  21. Radiometric Correction (a) Sensor Calibration: Computation of k and C (b) Radiometric correction for sensor instability (c) Determination of atmospheric influence parameters θ (flat terrain) = from astronomic ephemeris (replaced by ωfor inclined terrain) A. Dermanis

  22. Radiometric Correction (a) Sensor Calibration: Computation of k and C (b) Radiometric correction for sensor instability (c) Determination of atmospheric influence parameters θ (flat terrain) = from astronomic ephemeris (replaced by ωfor inclined terrain) φ = from satellite orbit A. Dermanis

  23. Radiometric Correction (a) Sensor Calibration: Computation of k and C (b) Radiometric correction for sensor instability (c) Determination of atmospheric influence parameters θ (flat terrain) = from astronomic ephemeris (replaced by ωfor inclined terrain) φ = from satellite orbit Tθ, Τφ= from atmospheric pressure, temperature, humidity A. Dermanis

  24. Radiometric Correction (a) Sensor Calibration: Computation of k and C (b) Radiometric correction for sensor instability (c) Determination of atmospheric influence parameters θ (flat terrain) = from astronomic ephemeris (replaced by ωfor inclined terrain) φ = from satellite orbit Tθ, Τφ= from atmospheric pressure, temperature, humidity ED, LP =from atmospheric conditions related to scattering processes (extremely difficult to access!) A. Dermanis

  25. Radiometric Correction (a) Sensor Calibration: Computation of k and C (b) Radiometric correction for sensor instability (c) Determination of atmospheric influence parameters θ (flat terrain) = from astronomic ephemeris (replaced by ωfor inclined terrain) φ = from satellite orbit Tθ, Τφ= from atmospheric pressure, temperature, humidity ED, LP =from atmospheric conditions related to scattering processes (extremely difficult to access!) computation of: A. Dermanis

  26. Radiometric Correction (a) Sensor Calibration: Computation of k and C (b) Radiometric correction for sensor instability (c) Determination of atmospheric influence parameters θ (flat terrain) = from astronomic ephemeris (replaced by ωfor inclined terrain) φ = from satellite orbit Tθ, Τφ= from atmospheric pressure, temperature, humidity ED, LP =from atmospheric conditions related to scattering processes (extremely difficult to access!) unknown ! computation of: A. Dermanis

  27. Radiometric Correction (a) Sensor Calibration: Computation of k and C (b) Radiometric correction for sensor instability (c) Determination of atmospheric influence parameters θ (flat terrain) = from astronomic ephemeris (replaced by ωfor inclined terrain) φ = from satellite orbit Tθ, Τφ= from atmospheric pressure, temperature, humidity ED, LP =from atmospheric conditions related to scattering processes (extremely difficult to access!) unknown ! computation of: (d) Radiometric correction for atmospheric influence A. Dermanis

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