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Image Based Prediction of Thermal Imaging Performance

Image Based Prediction of Thermal Imaging Performance. Saar Bobrov Yoav Y. Schechner Department of Electrical Engineering, Technion. Acknowledgement: Rafael Ltd. The Problem. Predict sensor performance Prior to operation In specific scenes. Bobrov & Schechner. Applications.

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Image Based Prediction of Thermal Imaging Performance

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  1. Image Based Prediction ofThermal Imaging Performance Saar Bobrov Yoav Y. Schechner Department of Electrical Engineering,Technion Acknowledgement: Rafael Ltd.

  2. The Problem • Predict sensor performance • Prior to operation • In specific scenes Bobrov & Schechner

  3. Applications • Space probes • Electro-optical missiles • Medical Probes Bobrov & Schechner

  4. Previous work • Performance based on imager characteristics • Ratches 75’; Wittenstein and Gal 03’ • Synthetic scenes • Wegner and Drake 00’; Toler and Grey 80’ • Image based/Example based: • Texture synthesis • Wei and Levoy 00’; Heeger and Bergen 95’ • Image analogies • Hertzman and Jacobs 01’; Drori and Cohen-or 03’

  5. Systems Introduction High quality Thermal Sight Simulation Hi-q imaging Hi-q Imaging parameters Scene radiance Low quality Missile seeker Lo-q imaging Lo-q Bobrov & Schechner

  6. From Photons to Gray Levels Scene Optical Assembly Photon Irradiance Photon Radiance Signal Processing Electronic Signal Gray level Image Detector Module Bobrov & Schechner

  7. Optical Assembly Lens Scanning mirror Body Cold filter Cold shield Bobrov & Schechner

  8. Atmospheric Transmittance

  9. Cold Shield Internal radiation Body Cold shield Internal radiation Detector Filter Internal radiation Bobrov & Schechner

  10. Optical Assembly Lens Scanning mirror Body Cold filter Cold shield Bobrov & Schechner

  11. Optical Functional Diagram Projection Blur Irradiance Photon Radiance Projected radiance Blurred radiance Photon irradiance Bobrov & Schechner

  12. Projection Scene radiance Detector Bobrov & Schechner

  13. Blur Optical PSF Bobrov & Schechner

  14. Irradiance Internal radiance Direct Reflected Camera body Scene radiance Detector Optics radiance Cold Shield Bobrov & Schechner

  15. From Photons to Gray Levels Scene Optical Assembly Photon Irradiance Photon Radiance Signal Processing Electronic Signal Gray level Image Detector Module Bobrov & Schechner

  16. Detector Circuit Integration switch Readout Output Photons Integration InSb Capacitor Bobrov & Schechner

  17. Detector Flow Diagram Photo- detection Crosstalk Photon irradiance Electron Flux Electron Flux Electric signal Readout Sampling Noise Electrons Bobrov & Schechner

  18. Photo-Detection Photons Electron Flux InSb Bobrov & Schechner

  19. Detector Flow Diagram Photo- detection Crosstalk Photon irradiance Electron Flux Electron Flux Electric signal Readout Sampling Noise Electrons Bobrov & Schechner

  20. Crosstalk Crosstalk PSF Photons Bobrov & Schechner

  21. Detector Flow Diagram Photo- detection Crosstalk Photon irradiance Electron Flux Electron Flux Electric signal Readout Sampling Noise Electrons Bobrov & Schechner

  22. Sampling Δxd α β Δyd Bobrov & Schechner

  23. Detector Flow Diagram Photo- detection Crosstalk Photon irradiance Electron Flux Electron Flux Electric signal Readout Sampling Noise Electrons Bobrov & Schechner

  24. Noise • Noise components: • Shot noise: • Residual Non-Uniformity Bobrov & Schechner

  25. Lo-q Non-Uniformity Bobrov & Schechner

  26. Hi-q Non-Uniformity Bobrov & Schechner

  27. Noise • Noise components: • Shot noise: • Residual non-uniformity • Excess noise • RMS noise amplitude: • Noisy image: Bobrov & Schechner

  28. Detector Flow Diagram Photo- detection Crosstalk Photon irradiance Electron Flux Electron Flux Electric signal Readout Sampling Noise Electrons Bobrov & Schechner

  29. From Photons to Gray Levels Scene Optical Assembly Photon Irradiance Photon Radiance Signal Processing Electronic Signal Gray level Image Detector Module Bobrov & Schechner

  30. Signal Processing Electric signal Median subtraction A/D Add Gray level image Bobrov & Schechner

  31. 255 I8bit(m,n) [Digital units] Vmin V (m,n) [volt] Vmax Analog to Digital Conversion Bobrov & Schechner

  32. Signal Processing Electric signal Median subtraction A/D Add Gray level image Bobrov & Schechner

  33. Median Subtraction • Omits large DC signal before A/D • Subtracts non-uniformity between detector elements Bobrov & Schechner

  34. Signal Processing Electric signal Median subtraction A/D Add Gray level image Bobrov & Schechner

  35. Line Add to Standard Format Detector Array 120 lines 240 lines Bobrov & Schechner

  36. Signal Processing Electric signal Median subtraction A/D Add Gray level image Bobrov & Schechner

  37. Problem • How does the scene look like??

  38. From Gray Levels to Photons Optical Assembly Hi-q image Photon Irradiance Photon Radiance Signal Processing Hi-q image Electronic Signal Grey level Image Detector Module Bobrov & Schechner

  39. Inversion Pitfalls • Deblurring Hi-q Image Lo-q Image … Hi-q Deblur … Simulated Scene … Lo-q Blur … Bobrov & Schechner

  40. Blur Frequency Response HHi-q HLo-q Bobrov & Schechner

  41. Deblur Operation 1/HHi-q HLo-q/HHi-q HLo-q Bobrov & Schechner

  42. Noise Handling • Hi-q image is noisy: • No inversion to noise • Adding Lo-q noise • Estimate Hi-q noise • Calculate Lo-q noise amplitude: Bobrov & Schechner

  43. Experiments Courtesy of Rafael Ltd.

  44. Hi-q Image Bobrov & Schechner

  45. Lo-q Image Bobrov & Schechner

  46. Simulated Image Bobrov & Schechner

  47. Lo-q Hi-q Simulation Bobrov & Schechner

  48. Hi-q Image Bobrov & Schechner

  49. Lo-q Image Bobrov & Schechner

  50. Simulated Image Bobrov & Schechner

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