Considerations of HDR Program Origination

Transcription

1 SMPTE Bits by the Bay Wednesday May 23rd, 2018 Considerations of HDR Program Origination L. Thorpe Canon USA Inc Canon U.S.A., Inc. 1

2 Agenda Terminology Human Visual System Basis of HDR Camera Dynamic Range Lenses and HDR Dolby PQ System for Digital Cinema On-set Management of HDR and WCG Canon U.S.A., Inc. 2

3 HDR-related Terminology Scene Illumination Canon U.S.A., Inc. 3

4 The Sun (or moon) in the outdoors ILLUMINATE the scene Illuminance (Lux) Studio Light in the indoors ILLUMINATE The scene Luminance (Nits) ILLUMINANCE Is measured in LUX Canon U.S.A., Inc. 4

5 Scene Illumination in the Real World Canon U.S.A., Inc. 5

6 Real World Scene Illuminance ( Lux ) Billion 100 Million Direct Sun Million Sunlight , Indoor Lighting Moonlight Starlight Canon U.S.A., Inc. 6

7 HDR-related Terminology An Introduction to Nits Canon U.S.A., Inc. 7

8 The Human Visual System (HVS) sees the scene as reflected illuminance which is called LUMINANCE LUMINANCE is Technically measured in Candelas per Square Meter Illuminance (Lux) Luminance (CD/m²) Canon U.S.A., Inc. 8

9 Image Courtesy of Dolby Canon U.S.A., Inc. 9

10 Human Visual System and HDR Canon U.S.A., Inc. 10

11 The Human Visual System has three separate mechanisms to deal with the enormous range of Scene Luminance Photopic (Cones) Real World Scene Luminance ( Nits ) Million 1 Million 10, Direct Sun Sunlight Indoor Lighting Mesopic (Rods + Cones) Moonlight Scotopic (Rods) Canon U.S.A., Inc Starlight

12 2 Luminance ( cd / m or nits ) Million Million Human Visual System Steady State DR , Under any specific viewing situation the HVS has a Steady State Dynamic Range of about 6000:1 Canon U.S.A., Inc. 12

13 2 Luminance ( cd / m or nits ) Million Human Visual System Steady State DR Million 10, The HVS Steady State Dynamic Range adapts to the specific scene illumination Canon U.S.A., Inc. 13

14 2 Luminance ( cd / m or nits ) Human Visual System Steady State DR 800, Million 1 Million 10, The HVS Steady State Dynamic Range adapts to the specific scene illumination Canon U.S.A., Inc. 14

15 HDR Considerations Limitation of Television Dynamic Range Canon U.S.A., Inc. 15

16 2 Display Luminance ( cd / m or nits ) Million Million Human Visual System Steady State DR , For most of the history of television the home display was the CRT with a limited Dynamic Range of about 1000: Consumer TV 6000:1 1000:1 Canon U.S.A., Inc. 16

17 HDR Considerations Industry Quest For High Dynamic Range (HDR) Canon U.S.A., Inc. 17

18 March of Consumer Display Technology 1000 nit More Highlight Detail Display Screen Luminance (Nits) 100 nit New 0.1 nit Current Consumer SDR More Lowlight Detail Consumer HDR 0.05 nit Canon U.S.A., Inc. 18

19 2012 Dolby Submission to ITU The new UHDTV signal should be able to represent via the EOTF a brightness range from nits to 10,000 nits, with non-linear code values such that contouring/stepping is never visible with the specified bit depths (10-12 bits) Canon U.S.A., Inc. 19

20 2 Display Luminance ( cd / m or nits ) Million Million Human Visual System Steady State DR , More Highlight Detail Dolby Vision More Lowlight Detail Canon U.S.A., Inc. 20

21 HDR Considerations Camera Dynamic Range Canon U.S.A., Inc. 21

22 Standard Dynamic Range (SDR) System Scene Camera System Transfer of Scene Referred Image Data Display Light OETF EOTF Display Light OETF Opto Electronic Transfer Function ITU-R BT.709 EOTF Electro Optical Transfer Function ITU-R BT.1886 Canon U.S.A., Inc. 22

23 Canon U.S.A., Inc. 23

24 Canon U.S.A., Inc. 24

25 BBC Production Wolf Hall Canon U.S.A., Inc. 25

26 Peak White 12 db 400 % 0 db 100% Nominal Exposed Reference White Luma Video Level 66.0 db Dynamic Range 2000:1 10 F-Stops Contrast Ratio 54 db 500:1 54 db CMOS Noise Floor Normalized Illumination F-Stops Canon U.S.A., Inc. 26

27 105 % 100 % Nonlinear Processed Video Output Rec 709 Camera White Clip Level Light Input % Canon U.S.A., Inc. 27

28 Linear Light Transfer Function +24 db 0 db Linear Luma Signal Level From Image Sensor - 68 db 1600 % (Limit of image sensor) Noise Floor 15-stops Exposure Latitude ISO 800 Reference Mapping Point 100 IRE Ref. White (from 89.9% reflectance white ) Peak White Light Reflectance in T-stops (Scene Illumination) Canon U.S.A., Inc. 28

29 105 % 100 % Nonlinear Processed Video Output Rec 709 Camera White Clip Level Logarithmic Light Input % Canon U.S.A., Inc. 29

30 Contemporary Log Curves ARRI Log C Canon Canon Log Panasonic V-Log RED RedLogFilm Sony S-Log 3 Canon U.S.A., Inc. 30

31 15-Stop Dynamic Range Camera Illumination Signal level Signal level T-Stop Lux mvolt IRE 32, Peak White (1440 % Reflectance) Reference White (90 % Reflectance) Reference Gray (18 % Reflectance) 1 % Black Level Canon U.S.A., Inc

32 15-Stop Dynamic Range Camera Illumination Signal level Signal level T-Stop Lux mvolt IRE 32, Peak White (1440 % Reflectance) Reference White (90 % Reflectance) Reference Gray (18 % Reflectance) 1 % Black Level Canon U.S.A., Inc

33 mv 0.39 IRE mv peak Stop 1.37 mv 0.20 IRE 0.73 mv peak Stop 0.68 mv 0.10 IRE 0.32 mv Peak Stop 0.34 mv 0.05 IRE Canon U.S.A., Inc. 33

34 Luma Signal to Noise 68 db on 700 mv Noise Floor 0.28 mv r.m.s Canon U.S.A., Inc. 34

35 mv 0.39 % mv peak Stop 1.37 mv 0.20 % 0.73 mv peak Stop 0.68 mv 0.28 mv r.m.s 0.10 % Stop 0.32 mv Peak 0.34 mv (Noise Floor) Approx. 0 db S / N 0.05 % Canon U.S.A., Inc. 35

36 Canon U.S.A., Inc. 36

37 Logarithmic OETF and Image Sensor Performance Canon U.S.A., Inc. 37

38 IRE[%] Canon Log 2 120% 100% 80% 60% 40% x y IRE[%] IRE[%] 0% 3.54% 20% 39.20% 100% 58.36% 6400% % 20% y ( x% ) = Log e x% ( ) % + 0% 0% 1000% 2000% 3000% 4000% 5000% 6000% 7000% 1600% IRE[%] Canon U.S.A., Inc. 38

39 Log-Log Scale The use of Linear Scales does not work well The solution is to focus on a Gray Point Use Mid-Gray as the Datum Rather than Black and White Canon U.S.A., Inc. 39

40 Log Image Luminance Camera Peak White Mid Gray Log Scene Luminance Camera Black Canon U.S.A., Inc. 40

41 Cinema Mapping Point +24 db 1600 % (Limit of image sensor) Peak White Linear Signal Level From Image Sensor Cine Reference Mapping Point 20 % (From 18% Gray Reflectance) 15-stops Exposure Latitude ISO 800 Noise Floor Light Reflectance in T-stops (Scene Illumination) Canon U.S.A., Inc. 41

42 bit Code Value Canon Log 2 Canon Log Canon U.S.A., Inc. 42 Relative Stop from 18% Grey

43 mv 1. 1 mv peak 10bit Code Value top 1.09 mv Canon Log 2 top top 0.54 mv peak 0.55 mv 0.28 mv Peak 0.27 mv Relative Stop from 18% Grey 0.28 mv r.m.s (Noise Floor) Approx. 0 db S / N Canon U.S.A., Inc. 43

44 mv 1. 1 mv peak 10bit Code Value Stop 1.09 mv Canon Log Relative Stop from 18% Grey Canon U.S.A., Inc. 44

45 Lenses and HDR Canon U.S.A., Inc. 45

46 Luminance Lens Dynamic Range The HDR Imaging System Peak White Camera Image Sensor Full Well Image Sensor Limit of HDR Capture Over exposed Signal Camera Dynamic Range 89.9% White Chip Lens Contrast Ratio Reference White Nominal Exposure Camera Contrast Ratio Optical Noise Floor Camera Noise Floor Super Black Canon U.S.A., Inc. 46

47 Lens Transmission High Dynamic Range Peak White Camera Image Sensor Full Well Image Sensor Limit of HDR Capture Over exposed Signal Camera Exposure Latitude 89.9% White Chip Lens Contrast Ratio Defines Tonal Reproduction of Nominally Exposed Scene Reference White Nominal Exposure Camera Contrast Ratio Optical Noise Floor Camera Noise Floor Super Black Canon U.S.A., Inc. 47

48 Lens Transmission High Dynamic Range Peak White Camera Image Sensor Full Well Image Sensor Limit of HDR Capture 89.9% White Chip Lens Contrast Ratio Defines Accurate Reproduction of Fine Scene Speculars Defines Tonal Reproduction of Nominally Exposed Scene Reference White Over exposed Signal Nominal Exposure Camera Contrast Ratio Camera Exposure Latitude Optical Noise Floor Camera Noise Floor Super Black Canon U.S.A., Inc. 48

49 Canon U.S.A., Inc. 49

50 Lens Transmission Strong Scene Highlights can Create Optical Artifacts High Dynamic Range Peak White Camera Image Sensor Full Well Image Sensor Limit of HDR Capture 89.9% White Chip Lens Contrast Ratio Defines Accurate Reproduction of Fine Scene Speculars Defines Tonal Reproduction of Nominally Exposed Scene Reference White Over exposed Signal Nominal Exposure Camera Contrast Ratio Camera Exposure Latitude Optical Noise Floor Camera Noise Floor Super Black Canon U.S.A., Inc. 50

51 Canon U.S.A., Inc. 51

52 Canon U.S.A., Inc. 52

53 Canon U.S.A., Inc. 53

54 Optomechanical Strategies Canon U.S.A., Inc. 54

55 While HDR +WCG Enhance Imagery Canon U.S.A., Inc. 55

56 While HDR +WCG Enhance Imagery There is a Dark Side Canon U.S.A., Inc. 56

57 Lateral R G B Color Misregistration B G R Longitudinal HD 4K Color Flare Canon U.S.A., Inc. 57

58 Canon U.S.A., Inc. 58

59 A small degree of chromatic aberration will be invisible in the SDR reproduction SDR Canon U.S.A., Inc. 59

60 A small degree of chromatic aberration will be invisible in the SDR reproduction The higher brightness of the HDR reproduction elevates the visibility of even a small degree of chromatic aberration SDR HDR Canon U.S.A., Inc. 60

61 New Imperatives in 4K UHD Optical Design Sharpness Maximize Lateral Chromatic Aberration Minimize Lens Design Goals Minimize Longitudinal Chromatic Aberration Color Gamut Optimize HDR Canon U.S.A., Inc. 61

62 4K UHD Lenses Sharpness 4K HD Lateral Chromatic Aberration Longitudinal Chromatic Aberration Color Gamut HDR Canon U.S.A., Inc. 62

63 HDR Considerations HDR Television is a System Canon U.S.A., Inc. 63

64 The HDR System Dilemma HDR Display HDR Production Broadcast Infrastructure HDR Video? SDR Display Canon U.S.A., Inc. 64

65 Dolby Labs Dolby Vision Proponent HDR Systems BBC Hybrid Log Gamma Philips Parameter Based HDR Samsung Dynamic Metadata Technicolor HDR Video Mastering and Distribution Workflow Canon U.S.A., Inc. 65

66 Contemporary Broadcast and Cinematography Cameras must anticipate diversity in: Production Formats HDR Systems Wide Color Gamuts Canon U.S.A., Inc. 66

67 Multiformat & Multipurpose Cameras Multiformat selection of: 4K UHD (3840 x 2160) 4K DCI (4096 x 2160) 2K DCI (2048 x 1080) HD (1920 x 1080) Multipurpose Selection of: HDR PQ / HLG / Native Log WCG BT / DCI P3 / Canon Cinema Canon U.S.A., Inc. 67

68 Digital Cinema / Episodic TV Canon Log2 Convert to Convert to PQ EOTF -1 HLG OETF PQ C Log2 HLG Select Live Television Canon U.S.A., Inc. 68

69 HDR Systemization for Non-realtime Productions Canon U.S.A., Inc. 69

70 Cinema Centric HDR System Dolby Vision Perceptual Quantization (PQ) System for HDR Canon U.S.A., Inc. 70

71 2012 Dolby Submission to ITU The non-linear transfer function should be specified as an EOTF It should be display referenced absolute luminance This will ensure that there is no ambiguity As to how the UHDTV signal should be displayed The major criterion for determining EOTF Will be the efficiency of digital code usage Canon U.S.A., Inc. 71

72 Display Referred System Camera Display Scene Light Rendering Intent PQ EOTF -1 PQ EOTF Display Light Encoding Decoding The PQ approach is defined by the Display EOTF Describes the Absolute light output from the Mastering display This is a Display Referred Image Data system Canon U.S.A., Inc. 72

73 500 Light 500 Nit Display Display EOTF EOTF 64 0 Digital Code Light Camera OETF OETF 500 Canon U.S.A., Inc. 73

74 PQ System Nit Display Nit Display Light EOTF Digital Code Digital Code Light OETF Mastering Canon U.S.A., Inc. 74

75 Nit Display 1000 PQ System 1000 Nit Display Nit Display Light EOTF Digital Code Digital Code Digital Code Light OETF Mastering Canon U.S.A., Inc. 75

76 Dolby Vision System Canon U.S.A., Inc. 76

77 HDR Considerations The Science behind PQ Canon U.S.A., Inc. 77

78 Human Contrast Sensitivity Function What is visually important is the contrast between the luminance of the background and the luminance of the circles Canon U.S.A., Inc. 78

79 Contrast Sensitivity Contrast Sensitivity = The discrimination capability of the human vision system = Ratio of luminances between two adjacent of similar luminance Y Y Canon U.S.A., Inc. 79

80 Contrast Sensitivity The human visual system is capable of distinguishing between two adjacent luminance levels that are about 1% apart Contrast Sensitivity: Y = Y + Y Y Y = ( ) / 100 = 1.01 Canon U.S.A., Inc. 80

81 Barten s Contrast Sensitivity Function Contouring / Stepping is Visible Contouring / Stepping is Invisible Canon U.S.A., Inc. 81

82 Canon U.S.A., Inc. 82

83 HDR Considerations On-Set Management of HDR and WCG Canon U.S.A., Inc. 83

84 ACES Academy Color Encoding System Platform for Motion Image Production, Mastering, and Archiving Canon U.S.A., Inc. 84

85 ACES Color Management Input Device Transform ACES Space Color Space that includes the entire Source IDT Image Visible RRT ODT Display Unique input Image Data converted into ACES Scene Referred System Spectrum Very High Dynamic Range Space Reference Rendering Transform Graded ACES image is converted to output referred image Output Device Transform Maps the image to the unique color space of the specific display System is Tailored for HDR and WCG Grading Display Referred System Canon U.S.A., Inc. 85

86 ACESproxy ACES Space UHD / HD IDT Color space that includes Wide Color Gamut RRT ODT 18-bit Processing Engine Display Canon U.S.A., Inc. 86

87 The HDR Reference Display C300 Mark II Source OETF Canon Log2 Or Canon Log 3 (10-bit) 4K RAW 10 / 12-bit ACES Color Space DeBayer IDT Linearizer CDL High Bit Depth RRT Display Thumb Drive ASC CDL Data ODT Color Space Transform (3D LUT) -1 EOTF (LUT) 10-bit Display Panel EOTF Grading Control Panel Canon U.S.A., Inc. 87

88 UHD / HD Signal Inputs (Nits) ? 1000 nit Display Panel Canon U.S.A., Inc. 88

89 1600 % Range Setting to Handle HDR Inputs HDR Management in the Reference Display 800% Compressed (in Display Processing) 400% Clipped (in Display Processing) 400% % Ref White Linearized Input Signal Pre-Processing (Display EOTF) Video to Panel (Digital Code) Canon U.S.A., Inc EOTF Maximum DCI Screen Luminance (Nits)

90 High bit depth HDR Clipping Mode 10-bit Display Panel Gamma EOTF Pre Processing Output Video Signal Output Applied to Panel % Linearized Input Signal Level Over maximum Nit is clipped Under maximum Nit is faithfully reproduced Canon U.S.A., Inc. 90

91 High bit depth HDR Compression Mode 10-bit Display Panel Gamma EOTF Pre Processing Output Video Signal Output Applied to Panel % Linearized input signal input Overall Brightness is reduced Gradation is faithfully reproduced Canon U.S.A., Inc. 91

92 Reference Display has ACES Grading Controls Built-in CDL R CDL G CDL B CDL Bypass Power Saturation Slope Offset Canon U.S.A., Inc. 92

93 Canon U.S.A., Inc. 93

94 False Color Metering for HDR igital Code Color Scale Canon U.S.A., Inc. 94

95 HDR Monitoring With False Color Metering and Extended Waveform Scaling Canon U.S.A., Inc. 95

96 Canon U.S.A., Inc. 96

97 Grade HDR while monitoring SDR Canon U.S.A., Inc. 97

98 Thank You for Your Attention Canon U.S.A., Inc. 98