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Le immagini ad alta dinamica            tra i limiti dei dispositivi e quelli                        della visione        ...
Outline                                   HDR imaging                        HDR in practice: measuring the limits        ...
The dynamic rangeFriday, June 10, 2011
Friday, June 10, 2011
Define HDR ?                           do we need a                        threshold number ?Friday, June 10, 2011
Define HDR ?                           do we need a                        threshold number ?                              ...
Define HDR                        A rendition of a scene with                        greater dynamic range than            ...
That is ?Friday, June 10, 2011
Friday, June 10, 2011
Annibale	  Carracci	  	  	  (1560-­‐1609)	  	  PaesaggioFriday, June 10, 2011
Photo: C. OleariFriday, June 10, 2011
Photo: C. OleariFriday, June 10, 2011
Annibale	  Carracci	  	  	  (1560-­‐1609)	  	  PaesaggioFriday, June 10, 2011
Source/lamp                  Average Luminance cd/           Light        Xenon	  short	  arc                             ...
Dynamic rangesFriday, June 10, 2011
Dynamic ranges                            ?Friday, June 10, 2011
Range limits and quantization:                the ‘salame’ metaphorFriday, June 10, 2011
Friday, June 10, 2011
Range compression                        from incorrect pixel perspectiveFriday, June 10, 2011
Range compression                        from incorrect pixel perspectiveFriday, June 10, 2011
Range compression                        from incorrect pixel perspective                    Very wide range obtained with...
The “salame” metaphor                          Dynamic range   QuantizationFriday, June 10, 2011
The “salame” metaphor                           Dynamic range      Quantization                         More bits do not m...
28=256                                         8 bit                                                 2-3 log unit         ...
28=256                                         8 bit                                                 2-3 log unit         ...
8 bit                           16 bit                                 2-3 log unit    Scene               Sensor         ...
Scene   Sensor           Scene   Sensor                  DR       DR              DR       DR                             ...
Scene   Sensor           Scene   Sensor                  DR       DR              DR       DR                             ...
The HDR idea                        http://www.adolfo.trinca.name/public/2010/11/                                      ahd...
The HDR idea                                                                How ?                                         ...
http://www.digitalcameratracker.com/how-to-create-high-                     definition-range-hdr-photos/Friday, June 10, 2011
Two sides of the coin             • Objective data: recording/displaying               physical light colorimetric distrib...
Mapping the world:                        the characteristic curveFriday, June 10, 2011
H&D          curveFriday, June 10, 2011
H&D          curveFriday, June 10, 2011
H&D          curveFriday, June 10, 2011
H&D          curveFriday, June 10, 2011
Olympus E-3                    http://www.dpreview.com/reviews/olympuse3/page21.aspFriday, June 10, 2011
Exposure problemFriday, June 10, 2011
Friday, June 10, 2011
Friday, June 10, 2011
History of HDR imagingFriday, June 10, 2011
HDR 1858                        H.P. Robinson “Fading AwayFriday, June 10, 2011
“The Fundamentals of Photography”                        Mees (1920) 2 negative printFriday, June 10, 2011
Ansel                        AdamsFriday, June 10, 2011
Ansel Adams - Zone System                                        ISCC 11/05-McCannFriday, June 10, 2011
Jones and Condit, 1941                  Measurements of dynamic range of real scenes                        REFLECTANCE RA...
L.A.Jones & H.R.Condit, JOSA,1941Friday, June 10, 2011
Retinex starting idea   digit ~ luminance 119                     119                                                    G...
1980Friday, June 10, 2011
Retinex cameraFriday, June 10, 2011
Capturing and reproducing                                the sceneFriday, June 10, 2011
Friday, June 10, 2011
Sensors dynamic range                              Limited !Friday, June 10, 2011
Is HDR a technological                         problem ?Friday, June 10, 2011
Expanding sensors dynamic range  • Sensors that compress their response to light due to their         logarithmic transfer...
Friday, June 10, 2011
Friday, June 10, 2011
The HDR idea                        http://www.adolfo.trinca.name/public/2010/11/                                      ahd...
The HDR idea                                          How ?                        http://www.adolfo.trinca.name/public/20...
Multiple image                         acquisitionFriday, June 10, 2011
CameraDigit = (radiance * time)                 • Multiple Exposures                        • Use Multiple Times          ...
Multiple Exposures                              Flux = Luminance * time                           Scene Luminance = Flux /...
Multiple Exposures                                                                    One Spot (ScaleD)                   ...
HDR file formats               Source: Reinhard et al., High Dynamic Range Imaging: Acquisition, Display, and             ...
HDR file formats               Source: Reinhard et al., High Dynamic Range Imaging: Acquisition, Display, and             ...
Acquisition limitsFriday, June 10, 2011
Friday, June 10, 2011
The glare problemFriday, June 10, 2011
The glare problemFriday, June 10, 2011
Friday, June 10, 2011
Effect of illumination                                   1.0 refl * 1.0 illum = 1.0 cd/m2                                  ...
Glare is image dependent                                         1.0 refl * 1.0 illum = 1.0 cd/m2                          ...
Ratio Signal/Glare                                1.0 cd/m2)/(0.000002) = 5*10^5                                  ( 0.002 ...
Sowerby, “Dictionary of Photography”, 1956Friday, June 10, 2011
Parasitic ImagesFriday, June 10, 2011
Camera limits           • Glare           • Unwanted scattered light in camera              • air - glass reflections      ...
Measuring overall camera glareFriday, June 10, 2011
Friday, June 10, 2011
HDR Test SetupFriday, June 10, 2011
digit 255 = 2094.2 cd/m2                         digit 0 = 0.11 cd/m2                                                    S...
20:1                        18,619:1                                   TargetsFriday, June 10, 2011
16 sec exposure - Target 1scaleBlackFriday, June 10, 2011
16 sec exposure - Target 4scaleBlackFriday, June 10, 2011
16 sec exposure - Target 4scaleBlackFriday, June 10, 2011
Target 1B                               Text                            Target 4B                             Text        ...
Constant Luminance - Variable SurroundFriday, June 10, 2011
Minimum GlareFriday, June 10, 2011
Mild GlareFriday, June 10, 2011
Maximum GlareFriday, June 10, 2011
Friday, June 10, 2011
Friday, June 10, 2011
4.3 log10 scene ----> 3.0 log10 image                            Scene  In-camera    Maximum           Scene           Dyn...
Side Dupe FilmFriday, June 10, 2011
Slide Dupe FilmFriday, June 10, 2011
One Negative Capture                                          4scale Black - Single Negative                              ...
Dynamic Range (OD)Friday, June 10, 2011
HDR from cameras                        • Range of usable captured information                        • Range of accurate ...
Courtesy: M. FairchildFriday, June 10, 2011
Glare insertion          Gregory Ward Larson, Holly Rushmeier, and Christine Piatko, “A Visibility Matching Tone Reproduct...
Display:                    measuring the human limitsFriday, June 10, 2011
Friday, June 10, 2011
Magnitude estimates (100-1)Friday, June 10, 2011
• Luminance does not correlate uniquely                        with appearance                 • No global tone scale can ...
Magnitude Estimation of Appearance                                            Change Surrounds                         100...
•White surround                      •adds glare                      •changes surround                        (simultaneo...
Center/Surround       Basic Unit          Gray test areas 12%          (small differences)                           Fixed...
90o rotationFriday, June 10, 2011
Friday, June 10, 2011
Testing different glares                             % of white surround                100%                              ...
Single & Double Density Transparencies                        Single =                                         2.7 log10 r...
5.4 & 2.7 log10 Ranges                   Constant Glare & SurroundFriday, June 10, 2011
White[100] = 0.0 rOD - Black [1] = 2.89 rOD                        100.0                         90.0                     ...
100                          90                          80                          70                                   ...
100                          90                                                                                 2.0 log10 ...
100                         90                                                                                5.0 log10 un...
100                         90                                                                                5.0 log10 un...
Measurements of apparent             range   (depends on area of white)         •100% = 2.0 log units                     ...
DD   DD   DD   DDFriday, June 10, 2011
Test summary          • Double transmission contrast                • Double dynamic range                        • very s...
What is on the retina:                   calculated retinal luminanceFriday, June 10, 2011
Friday, June 10, 2011
What comes to the retina is           different from the image                        High glare   Low glareFriday, June 1...
Veiling glare increases                                gray luminance                                                     ...
Discussion                 • Glare lowers the physical contrast                 • Spatial comparisons increase the        ...
Glare Spread Function     1Vos, J.J. and van den Berg, T.J.T.P,     CIE Research note 135/1, “Disability Glare”, ISBN 3900...
Glare Spread Function                                      Plotted in log scaleFriday, June 10, 2011
Dynamic Range = 5.4 OD                    or 251,189:1                        False-color LookUpTable (LUT)Friday, June 10...
Same LUT applied to SD & DD                            Visualize HDR targetsFriday, June 10, 2011
Retinal imageFriday, June 10, 2011
Same LUT applied to SD & DD                          Visualize Retinal ImagesFriday, June 10, 2011
Same LUT applied to SD & DD                        Change LUT for Retinal ImagesFriday, June 10, 2011
Change LUT for Retinal ImagesFriday, June 10, 2011
Scene              Retina     Appearance     1,000,000:1         100:1        1,000:1                         Spatial     ...
RangesFriday, June 10, 2011
Tone-rendering problem and                     spatial comparisonsFriday, June 10, 2011
Friday, June 10, 2011
Choosing a rendering intentFriday, June 10, 2011
124Friday, June 10, 2011
124Friday, June 10, 2011
Friday, June 10, 2011
Friday, June 10, 2011
Friday, June 10, 2011
Land experimentFriday, June 10, 2011
Land experimentFriday, June 10, 2011
Land experiment                        ProjectorFriday, June 10, 2011
Land experiment                        ProjectorFriday, June 10, 2011
Land experiment       ES=100 EM=100 EL=100                        ProjectorFriday, June 10, 2011
Land experiment       ES=100 EM=100 EL=100                        Projector        ColorimeterFriday, June 10, 2011
Land experiment       ES=100 EM=100 EL=100           LS=255 LM=115 LL=255                        Projector          Colori...
Land experiment    Observer       ES=100 EM=100 EL=100           LS=255 LM=115 LL=255                        Projector    ...
Land experiment                        PINK    Observer       ES=100 EM=100 EL=100            LS=255 LM=115 LL=255        ...
Land experiment    Observer                        Projector        ColorimeterFriday, June 10, 2011
Land experiment    Observer       ES=50 EM=111 EL=50                        Projector        ColorimeterFriday, June 10, 2...
Land experiment    Observer       ES=50 EM=111 EL=50             LS=128 LM=128 LL=128                        Projector    ...
Land experiment                        PINK    Observer       ES=50 EM=111 EL=50              LS=128 LM=128 LL=128        ...
Land experiment                        GRAY                        PINK    Observer       ES=50 EM=111 EL=50              ...
visual sensationFriday, June 10, 2011
HVS:                        local compression of rangeFriday, June 10, 2011
HVS:                        local compression of rangeFriday, June 10, 2011
Tone mapping vs Tone rendering                        No tone mapping operator (global)                                can...
Black and White MondrianFriday, June 10, 2011
HP 945 Images without “Frames of Reference”Friday, June 10, 2011
Some examplesFriday, June 10, 2011
Friday, June 10, 2011
Bob Sobol, HPR. Sobol, “ Improving the Retinex algorithm               for rendering    wide dynamic range photographs”, i...
Friday, June 10, 2011
ACE                                    Original   ACE             Original   ACEFriday, June 10, 2011
STRESS                        Tone RenderingFriday, June 10, 2011
Judging the resultsFriday, June 10, 2011
Beauty contest     C. Gatta, A. Rizzi, D. Marini, “Perceptually inspired HDR images tone mapping with color correction”, J...
HDR is in the middle                          Glare                               Post-LUT                         Sensor ...
SummaryFriday, June 10, 2011
•       To understand HDR we need a new perspective!                 1.Veiling glare limits the range on the retina       ...
Take home points                        • HDR limits are not (only) technological                        • Glare limits bo...
Take home points                        HDR works very well                          • because preserves image            ...
References             • J. J. McCann, A. Rizzi, “Camera and visual veiling glare in HDR images”               Journal of ...
The art and science of HDR imaging                                J.J. McCann, A. Rizzi                               (exp...
Thank you                        alessandro.rizzi@unimi.itFriday, June 10, 2011
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High dynamic images between devices and vision limits

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Alessandro Rizzi, University of Milan, lecture at Media Integration and Communication Center 10/06/2011

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Transcript of "High dynamic images between devices and vision limits"

  1. 1. Le immagini ad alta dinamica tra i limiti dei dispositivi e quelli della visione Alessandro Rizzi Dipartimento di Informatica e Comunicazione Università degli Studi di MilanoFriday, June 10, 2011
  2. 2. Outline HDR imaging HDR in practice: measuring the limits Using HDRFriday, June 10, 2011
  3. 3. The dynamic rangeFriday, June 10, 2011
  4. 4. Friday, June 10, 2011
  5. 5. Define HDR ? do we need a threshold number ?Friday, June 10, 2011
  6. 6. Define HDR ? do we need a threshold number ? NOFriday, June 10, 2011
  7. 7. Define HDR A rendition of a scene with greater dynamic range than the reproduction mediaFriday, June 10, 2011
  8. 8. That is ?Friday, June 10, 2011
  9. 9. Friday, June 10, 2011
  10. 10. Annibale  Carracci      (1560-­‐1609)    PaesaggioFriday, June 10, 2011
  11. 11. Photo: C. OleariFriday, June 10, 2011
  12. 12. Photo: C. OleariFriday, June 10, 2011
  13. 13. Annibale  Carracci      (1560-­‐1609)    PaesaggioFriday, June 10, 2011
  14. 14. Source/lamp Average Luminance cd/ Light Xenon  short  arc m2 200  000  ÷  5  000  000  000 levels Sun Metal  halide 1  600  000  000 10  000  000  ÷  60  000  000 Incandescent 20  000  000  ÷  26  000  000 compact  Fluorescent   20  000  ÷  70  000 Fluorescent 5  000  ÷  30  000 Sunlit  clouds 10  000 Candle 7  500 blue  sky 5  000 Preferred  values  for   50  ÷  500 indoor  lighIng White  paper  at  sun 10  000 White  paper  at  500  lx 100 White  paper  at  5  lx 1 Courtesy: C. OleariFriday, June 10, 2011
  15. 15. Dynamic rangesFriday, June 10, 2011
  16. 16. Dynamic ranges ?Friday, June 10, 2011
  17. 17. Range limits and quantization: the ‘salame’ metaphorFriday, June 10, 2011
  18. 18. Friday, June 10, 2011
  19. 19. Range compression from incorrect pixel perspectiveFriday, June 10, 2011
  20. 20. Range compression from incorrect pixel perspectiveFriday, June 10, 2011
  21. 21. Range compression from incorrect pixel perspective Very wide range obtained with isolated stimuli impossible to obtain in an imageFriday, June 10, 2011
  22. 22. The “salame” metaphor Dynamic range QuantizationFriday, June 10, 2011
  23. 23. The “salame” metaphor Dynamic range Quantization More bits do not mean wider range Less bits do not mean shorter rangeFriday, June 10, 2011
  24. 24. 28=256 8 bit 2-3 log unit Scene Sensor DR DR 216=65536 16 bit 4-5 log unitFriday, June 10, 2011
  25. 25. 28=256 8 bit 2-3 log unit Scene DR Sensor DR NO 216=65536 16 bit 4-5 log unitFriday, June 10, 2011
  26. 26. 8 bit 16 bit 2-3 log unit Scene Sensor Scene Sensor DR DR DR DR 8 bit 16 bit 4-5 log unitFriday, June 10, 2011
  27. 27. Scene Sensor Scene Sensor DR DR DR DR 8 bit 16 bitFriday, June 10, 2011
  28. 28. Scene Sensor Scene Sensor DR DR DR DR 8 bit 16 bitFriday, June 10, 2011
  29. 29. The HDR idea http://www.adolfo.trinca.name/public/2010/11/ ahdrdiagram.jpgFriday, June 10, 2011
  30. 30. The HDR idea How ? general solution ? rendering intent ? http://www.adolfo.trinca.name/public/2010/11/ ahdrdiagram.jpgFriday, June 10, 2011
  31. 31. http://www.digitalcameratracker.com/how-to-create-high- definition-range-hdr-photos/Friday, June 10, 2011
  32. 32. Two sides of the coin • Objective data: recording/displaying physical light colorimetric distribution • Subjective data: reproducing appearance (or different rendering intent)Friday, June 10, 2011
  33. 33. Mapping the world: the characteristic curveFriday, June 10, 2011
  34. 34. H&D curveFriday, June 10, 2011
  35. 35. H&D curveFriday, June 10, 2011
  36. 36. H&D curveFriday, June 10, 2011
  37. 37. H&D curveFriday, June 10, 2011
  38. 38. Olympus E-3 http://www.dpreview.com/reviews/olympuse3/page21.aspFriday, June 10, 2011
  39. 39. Exposure problemFriday, June 10, 2011
  40. 40. Friday, June 10, 2011
  41. 41. Friday, June 10, 2011
  42. 42. History of HDR imagingFriday, June 10, 2011
  43. 43. HDR 1858 H.P. Robinson “Fading AwayFriday, June 10, 2011
  44. 44. “The Fundamentals of Photography” Mees (1920) 2 negative printFriday, June 10, 2011
  45. 45. Ansel AdamsFriday, June 10, 2011
  46. 46. Ansel Adams - Zone System ISCC 11/05-McCannFriday, June 10, 2011
  47. 47. Jones and Condit, 1941 Measurements of dynamic range of real scenes REFLECTANCE RANGE OF PRINTS SCENE RANGE OF WORLD Minimum Average of 126 outdoor scenes Maximum 0.0 1.5 3.0 log rangeFriday, June 10, 2011
  48. 48. L.A.Jones & H.R.Condit, JOSA,1941Friday, June 10, 2011
  49. 49. Retinex starting idea digit ~ luminance 119 119 Green record 55 146 88 230 ratio = ratio = 0.62 0.62 Ratios are constant in sun and shadeFriday, June 10, 2011
  50. 50. 1980Friday, June 10, 2011
  51. 51. Retinex cameraFriday, June 10, 2011
  52. 52. Capturing and reproducing the sceneFriday, June 10, 2011
  53. 53. Friday, June 10, 2011
  54. 54. Sensors dynamic range Limited !Friday, June 10, 2011
  55. 55. Is HDR a technological problem ?Friday, June 10, 2011
  56. 56. Expanding sensors dynamic range • Sensors that compress their response to light due to their logarithmic transfer function; • Multimode sensors that have a linear and a logarithmic response at dark and bright illumination levels, (switches between linear and logarithmic modes of operation); • Sensors with a capacity well adjustment method; • Frequency-based sensors, sensor output is converted into pulse frequency; • Time-to-saturation [(TTS); time-to-first spike] sensors, signal is the time the to saturated pixel; • Sensors with global control over the integration time; • Sensors with autonomous control over the integration time, where each pixel has control over its own exposure. Spivak A, Belenky A, Fish A & Yadid-Pecht O (2009) Wide dynamic-range CMOS image sensors: A comparative performance analysis, IEEE Trans. on Electron Devices, 56, 2446-2461.Friday, June 10, 2011
  57. 57. Friday, June 10, 2011
  58. 58. Friday, June 10, 2011
  59. 59. The HDR idea http://www.adolfo.trinca.name/public/2010/11/ ahdrdiagram.jpgFriday, June 10, 2011
  60. 60. The HDR idea How ? http://www.adolfo.trinca.name/public/2010/11/ ahdrdiagram.jpgFriday, June 10, 2011
  61. 61. Multiple image acquisitionFriday, June 10, 2011
  62. 62. CameraDigit = (radiance * time) • Multiple Exposures • Use Multiple Times • Recover scene radiances at all pixels from camera digits New goal: Accurately measure radiancesFriday, June 10, 2011
  63. 63. Multiple Exposures Flux = Luminance * time Scene Luminance = Flux / time Scene Luminance = Camera Digit / timeFriday, June 10, 2011
  64. 64. Multiple Exposures One Spot (ScaleD) 250 200 1/8 sec 1/4 sec 1/2 sec Camera Digit 150 Camera 1 sec 2 sec 4 sec Digit 100 8 sec 16 sec 32 sec 64 sec 50 FIT 0 0.0001 0.0010 0.0100 0.1000 1.0000 10.0000 100.0000 1000.0000 Exposure Flux [(cd/m2) * sec] Flux = Luminance * timeFriday, June 10, 2011
  65. 65. HDR file formats Source: Reinhard et al., High Dynamic Range Imaging: Acquisition, Display, and Image-Based Lighting (The Morgan Kaufmann Series in Computer Graphics)Friday, June 10, 2011
  66. 66. HDR file formats Source: Reinhard et al., High Dynamic Range Imaging: Acquisition, Display, and Image-Based Lighting (The Morgan Kaufmann Series in Computer Graphics)Friday, June 10, 2011
  67. 67. Acquisition limitsFriday, June 10, 2011
  68. 68. Friday, June 10, 2011
  69. 69. The glare problemFriday, June 10, 2011
  70. 70. The glare problemFriday, June 10, 2011
  71. 71. Friday, June 10, 2011
  72. 72. Effect of illumination 1.0 refl * 1.0 illum = 1.0 cd/m2 0.2 refl *0.01 illum = 0.002 cd/m2 Assumes 0.0 glareFriday, June 10, 2011
  73. 73. Glare is image dependent 1.0 refl * 1.0 illum = 1.0 cd/m2 0.002 cd/m2 *0.001 = 0.000002 0.001 1.0 cd/m2 *0.001 = 0.001 0.001 0.2 refl *0.01 illum = 0.002 cd/m2 Assumes 0.001 glareFriday, June 10, 2011
  74. 74. Ratio Signal/Glare 1.0 cd/m2)/(0.000002) = 5*10^5 ( 0.002 cd/m2)) / (0.001) = 2 Assumes 0.001 glareFriday, June 10, 2011
  75. 75. Sowerby, “Dictionary of Photography”, 1956Friday, June 10, 2011
  76. 76. Parasitic ImagesFriday, June 10, 2011
  77. 77. Camera limits • Glare • Unwanted scattered light in camera • air - glass reflections • lens (number of elements) • aperture • angle off optical axis • camera wall reflections • sensor surface reflections • We must measure actual veiling glare limitFriday, June 10, 2011
  78. 78. Measuring overall camera glareFriday, June 10, 2011
  79. 79. Friday, June 10, 2011
  80. 80. HDR Test SetupFriday, June 10, 2011
  81. 81. digit 255 = 2094.2 cd/m2 digit 0 = 0.11 cd/m2 Synthetic HDR (High-Dynamic Range) Images Text 18,619:1 Goal Image 2094.2 cd/m2 = 18,619 0.11 cd/m2Friday, June 10, 2011
  82. 82. 20:1 18,619:1 TargetsFriday, June 10, 2011
  83. 83. 16 sec exposure - Target 1scaleBlackFriday, June 10, 2011
  84. 84. 16 sec exposure - Target 4scaleBlackFriday, June 10, 2011
  85. 85. 16 sec exposure - Target 4scaleBlackFriday, June 10, 2011
  86. 86. Target 1B Text Target 4B Text Target 4W 16 sec exposureFriday, June 10, 2011
  87. 87. Constant Luminance - Variable SurroundFriday, June 10, 2011
  88. 88. Minimum GlareFriday, June 10, 2011
  89. 89. Mild GlareFriday, June 10, 2011
  90. 90. Maximum GlareFriday, June 10, 2011
  91. 91. Friday, June 10, 2011
  92. 92. Friday, June 10, 2011
  93. 93. 4.3 log10 scene ----> 3.0 log10 image Scene In-camera Maximum Scene Dynamic Accurate Error Range Range (% radiance) 1scaleB 20:1 20:1 0 4scaleB 18,619:1 3,000:1 1 300% Min 4scaleW 18,619:1 100:1 10,000% Max Measure In-camera AccuracyFriday, June 10, 2011
  94. 94. Side Dupe FilmFriday, June 10, 2011
  95. 95. Slide Dupe FilmFriday, June 10, 2011
  96. 96. One Negative Capture 4scale Black - Single Negative 2.50 3.5 Log10 units 2.30 2.10 Log digit 1.90 1.70 1.50 -1.00 -0.50 0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 Log Cd/m2Friday, June 10, 2011
  97. 97. Dynamic Range (OD)Friday, June 10, 2011
  98. 98. HDR from cameras • Range of usable captured information • Range of accurate luminance information (much smaller) • Scene dependentFriday, June 10, 2011
  99. 99. Courtesy: M. FairchildFriday, June 10, 2011
  100. 100. Glare insertion Gregory Ward Larson, Holly Rushmeier, and Christine Piatko, “A Visibility Matching Tone Reproduction Operator for High Dynamic Range Scenes”, IEEE Trans on VISUALIZATION AND COMPUTER GRAPHICS, VOL. 3, NO. 4, oct-dec 1997Friday, June 10, 2011
  101. 101. Display: measuring the human limitsFriday, June 10, 2011
  102. 102. Friday, June 10, 2011
  103. 103. Magnitude estimates (100-1)Friday, June 10, 2011
  104. 104. • Luminance does not correlate uniquely with appearance • No global tone scale can render the appearanceFriday, June 10, 2011
  105. 105. Magnitude Estimation of Appearance Change Surrounds 100 90 Magnitude Estimation 80 70 60 50 40 30 20 10 0 0.10 1.00 10.00 100.00 1000.00 10000.00 Log Luminance (cd/m2) Min [0 cd/m2] Max [2094 cd/m2]Friday, June 10, 2011
  106. 106. •White surround •adds glare •changes surround (simultaneous contrast) We need a new range target •Vary dynamic range with •constant glare •contrast surroundFriday, June 10, 2011
  107. 107. Center/Surround Basic Unit Gray test areas 12% (small differences) Fixed contrast surround 88%Friday, June 10, 2011
  108. 108. 90o rotationFriday, June 10, 2011
  109. 109. Friday, June 10, 2011
  110. 110. Testing different glares % of white surround 100% 50% 0%Friday, June 10, 2011
  111. 111. Single & Double Density Transparencies Single = 2.7 log10 range Double = (superimposed) 5.4 log10 rangeFriday, June 10, 2011
  112. 112. 5.4 & 2.7 log10 Ranges Constant Glare & SurroundFriday, June 10, 2011
  113. 113. White[100] = 0.0 rOD - Black [1] = 2.89 rOD 100.0 90.0 80.0 70.0 magnitude estimation 60.0 50.0 40.0 30.0 50% white surround 20.0 10.0 0.0 6 5 4 3 2 1 0 relative optical density 50% Single DensityFriday, June 10, 2011
  114. 114. 100 90 80 70 2.3 log10 units magnitude estimation 60 50 40 50% white 30 surround 20 10 0 6 5 4 3 2 1 0 relative optical density 50% Double Density 50% Single DensityFriday, June 10, 2011
  115. 115. 100 90 2.0 log10 units 80 70 magnitude estimation 60 50 40 100% white surround 30 20 10 0 6 5 4 3 2 1 0 relative optical density White Double Density White Single DensityFriday, June 10, 2011
  116. 116. 100 90 5.0 log10 units 80 70 magnitude estimation 60 50 40 0% white 30 surround 20 10 0 6 5 4 3 2 1 0 relative optical density Black Double Density Black Single DensityFriday, June 10, 2011
  117. 117. 100 90 5.0 log10 units 80 Over 20 70 not big improvement magnitude estimation 60 50 40 0% white 30 surround 20 10 0 6 5 4 3 2 1 0 relative optical density Black Double Density Black Single DensityFriday, June 10, 2011
  118. 118. Measurements of apparent range (depends on area of white) •100% = 2.0 log units 10 • 50% = 2.3 log units 10 • 8% = 2.9 log units 10Friday, June 10, 2011
  119. 119. DD DD DD DDFriday, June 10, 2011
  120. 120. Test summary • Double transmission contrast • Double dynamic range • very small change in appearance range • Visual limit ~ area of white surround • area of white controls glareFriday, June 10, 2011
  121. 121. What is on the retina: calculated retinal luminanceFriday, June 10, 2011
  122. 122. Friday, June 10, 2011
  123. 123. What comes to the retina is different from the image High glare Low glareFriday, June 10, 2011
  124. 124. Veiling glare increases gray luminance Contrast offsets glare Contrast decreases gray appearance Glare vs. ContrastFriday, June 10, 2011
  125. 125. Discussion • Glare lowers the physical contrast • Spatial comparisons increase the contrast of appearance. • The two act in opposition. • Change with distance are different and the cancellation is far from exact.Friday, June 10, 2011
  126. 126. Glare Spread Function 1Vos, J.J. and van den Berg, T.J.T.P, CIE Research note 135/1, “Disability Glare”, ISBN 3900734976 (1999). PIGMENT Blue eyed Caucasian 1.21 Blue green Caucasian 1.02 Mean over all Caucasian 1.00 Brown eyed Caucasian 0.50 Non Caucasian with pigmented skin and dark brown eyes 0.00Friday, June 10, 2011
  127. 127. Glare Spread Function Plotted in log scaleFriday, June 10, 2011
  128. 128. Dynamic Range = 5.4 OD or 251,189:1 False-color LookUpTable (LUT)Friday, June 10, 2011
  129. 129. Same LUT applied to SD & DD Visualize HDR targetsFriday, June 10, 2011
  130. 130. Retinal imageFriday, June 10, 2011
  131. 131. Same LUT applied to SD & DD Visualize Retinal ImagesFriday, June 10, 2011
  132. 132. Same LUT applied to SD & DD Change LUT for Retinal ImagesFriday, June 10, 2011
  133. 133. Change LUT for Retinal ImagesFriday, June 10, 2011
  134. 134. Scene Retina Appearance 1,000,000:1 100:1 1,000:1 Spatial Spatial Glare Contrast Two scene-dependent spatial mechanisms: glare and contrast Glare masks the strength of spatial contrastFriday, June 10, 2011
  135. 135. RangesFriday, June 10, 2011
  136. 136. Tone-rendering problem and spatial comparisonsFriday, June 10, 2011
  137. 137. Friday, June 10, 2011
  138. 138. Choosing a rendering intentFriday, June 10, 2011
  139. 139. 124Friday, June 10, 2011
  140. 140. 124Friday, June 10, 2011
  141. 141. Friday, June 10, 2011
  142. 142. Friday, June 10, 2011
  143. 143. Friday, June 10, 2011
  144. 144. Land experimentFriday, June 10, 2011
  145. 145. Land experimentFriday, June 10, 2011
  146. 146. Land experiment ProjectorFriday, June 10, 2011
  147. 147. Land experiment ProjectorFriday, June 10, 2011
  148. 148. Land experiment ES=100 EM=100 EL=100 ProjectorFriday, June 10, 2011
  149. 149. Land experiment ES=100 EM=100 EL=100 Projector ColorimeterFriday, June 10, 2011
  150. 150. Land experiment ES=100 EM=100 EL=100 LS=255 LM=115 LL=255 Projector ColorimeterFriday, June 10, 2011
  151. 151. Land experiment Observer ES=100 EM=100 EL=100 LS=255 LM=115 LL=255 Projector ColorimeterFriday, June 10, 2011
  152. 152. Land experiment PINK Observer ES=100 EM=100 EL=100 LS=255 LM=115 LL=255 Projector ColorimeterFriday, June 10, 2011
  153. 153. Land experiment Observer Projector ColorimeterFriday, June 10, 2011
  154. 154. Land experiment Observer ES=50 EM=111 EL=50 Projector ColorimeterFriday, June 10, 2011
  155. 155. Land experiment Observer ES=50 EM=111 EL=50 LS=128 LM=128 LL=128 Projector ColorimeterFriday, June 10, 2011
  156. 156. Land experiment PINK Observer ES=50 EM=111 EL=50 LS=128 LM=128 LL=128 Projector ColorimeterFriday, June 10, 2011
  157. 157. Land experiment GRAY PINK Observer ES=50 EM=111 EL=50 LS=128 LM=128 LL=128 Projector ColorimeterFriday, June 10, 2011
  158. 158. visual sensationFriday, June 10, 2011
  159. 159. HVS: local compression of rangeFriday, June 10, 2011
  160. 160. HVS: local compression of rangeFriday, June 10, 2011
  161. 161. Tone mapping vs Tone rendering No tone mapping operator (global) can mimic vision We need an image dependent tone renderer operator (local)Friday, June 10, 2011
  162. 162. Black and White MondrianFriday, June 10, 2011
  163. 163. HP 945 Images without “Frames of Reference”Friday, June 10, 2011
  164. 164. Some examplesFriday, June 10, 2011
  165. 165. Friday, June 10, 2011
  166. 166. Bob Sobol, HPR. Sobol, “ Improving the Retinex algorithm for rendering wide dynamic range photographs”, in Human Vision and Electronic Imaging VII, B. E. Rogowitz and T. N.Pappas, ed., Proc. SPIE 4662-41, 341-348, 2002.Friday, June 10, 2011
  167. 167. Friday, June 10, 2011
  168. 168. ACE Original ACE Original ACEFriday, June 10, 2011
  169. 169. STRESS Tone RenderingFriday, June 10, 2011
  170. 170. Judging the resultsFriday, June 10, 2011
  171. 171. Beauty contest C. Gatta, A. Rizzi, D. Marini, “Perceptually inspired HDR images tone mapping with color correction”, Journal of Imaging Systems and Technology, Volume 17 Issue 5, pp. 285-294 (2007).Friday, June 10, 2011
  172. 172. HDR is in the middle Glare Post-LUT Sensor Spatial graphics Pre-LUT Algorithm card Image Spatial Scene in CPU Image Display memory in CPUFriday, June 10, 2011
  173. 173. SummaryFriday, June 10, 2011
  174. 174. • To understand HDR we need a new perspective! 1.Veiling glare limits the range on the retina 2. Neural processing (spatial) determines appearance 3. Neural is stronger than it appears [neural cancels glare] 4. General Solution requires spatial process [mimic vision] 5. Tone-Scale is limited, we need Tone-rendering [scene dependent]Friday, June 10, 2011
  175. 175. Take home points • HDR limits are not (only) technological • Glare limits both acquisition and vision • Glare is scene dependent • Human vision use spatial comparison to overcome this limit • Tone renderer operator can use the same approachFriday, June 10, 2011
  176. 176. Take home points HDR works very well • because preserves image information • not because are more accurate (not possible)Friday, June 10, 2011
  177. 177. References • J. J. McCann, A. Rizzi, “Camera and visual veiling glare in HDR images” Journal of the Society for Information Display 15/9, 721–730 (2007). • J. J. McCann, “Art, Science and Appearance in HDR” Journal of the Society for Information Display 15/9, 709–719 (2007). • A. Rizzi, J. J. McCann, “Glare-limited Appearances in HDR Images”, Journal of the Society for Information Display, 17/1, pp. 3-12, (2009). • J. J. McCann, A. Rizzi, “Retinal HDR Images: Intraocular Glare and Object Size” Journal of the Society for Information Display, 17/11, pp. 913-920, (2009).Friday, June 10, 2011
  178. 178. The art and science of HDR imaging J.J. McCann, A. Rizzi (expected publication date autumn 2011)Friday, June 10, 2011
  179. 179. Thank you alessandro.rizzi@unimi.itFriday, June 10, 2011
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