Engineering:High dynamic range

From HandWiki
Short description: Enhanced signal representation in digital media


High dynamic range (HDR), also known as wide dynamic range, extended dynamic range, or expanded dynamic range, is a signal with a higher dynamic range than usual.

The term is often used in discussing the dynamic ranges of images, videos, audio or radio. It may also apply to the means of recording, processing, and reproducing such signals including analog and digitized signals.[1]

Imaging

In this context, the term high dynamic range means there is a large amount of variation in light levels within a scene or an image. The dynamic range refers to the range of luminosity between the brightest area and the darkest area of that scene or image.

High dynamic range imaging (HDRI) refers to the set of imaging technologies and techniques that allow the dynamic range of images or videos to be increased. It covers the acquisition, creation, storage, distribution and display of images and videos.[2]

Modern films have often been shot with cameras featuring a higher dynamic range, and legacy films can be post-converted even if manual intervention will be needed for some frames (as when black-and-white films are converted to color). Also, special effects, especially those that mix real and synthetic footage, require both HDR shooting and rendering.{{Citation needed|date=December 2016} ions that demand high accuracy for capturing temporal aspects of changes in the scene. This is important in monitoring of some industrial processes such as welding, in predictive driver assistance systems in automotive industry, in surveillance video systems, and other applications.

Capture

Main article: Multi-exposure HDR capture

In photography and videography, a technique, commonly named high dynamic range (HDR) allows the dynamic range of photos and videos to be captured beyond the native capability of the camera. It consists of capturing multiple frames of the same scene but with different exposures and then combining them into one, resulting in an image with a dynamic range higher than the individually captured frames.[3][4]


Modern CMOS image sensors can often capture high dynamic range images from a single exposure.[5] This reduces the need to use the multi-exposure HDR capture technique.


Rendering

Main article: High-dynamic-range rendering

High-dynamic-range rendering (HDRR) is the real-time rendering and display of virtual environments using a dynamic range of 65,535:1 or higher (used in computer, gaming, and entertainment technology).[6] HDRR does not require a HDR display and originally used tone mapping to display the rendering on a standard dynamic range display.

Dynamic range compression or expansion

Main article: Tone mapping

Storage

High-dynamic-range formats for image and video files are able to store more dynamic range than traditional 8-bit gamma formats. These formats include:

  • HDR formats that can be used for both storage and transmission to HDR displays, such as:
    • For video:
    • For images:
      • Gain map approaches, which adds a conversion layer on top of SDR data. The result is backwards compatible with SDR displays and storage.
        • ISO 21496-1 Gain Map, evolved from a unification of Apple and Adobe's proposals.[7] Used by Apple under the name Adaptive HDR.[8] It is supported starting with macOS 15, iOS 18, iPadOS 18, Android 15, and Chromium based browsers.[9]
        • Apple Gain Map, which is not fully documented publicly, although documentation is available to decode these images.[10]
        • Adobe Gain Map, a gain map image in a JPEG image file;[11] used by Google under the name Ultra HDR and by Samsung under the name Super HDR.[12][10][13] Supports gain on 1 or 3 channels.[11] The Ultra HDR and ISO 21496-1 formats are encoded simultaneously in Android 15.[9][12]
        • AVIF is compatible with gain maps, but currently no encoder is available.[14]
      • Apple EDR (Extreme Dynamic Range), used in macOS and iOS.[15] Apple refers to EDR as the combination of hardware and software that allows displaying SDR and HDR content on the same screen.[16]
      • HEIC (HEVC codec in HEIF file format)
      • AVIF (AV1 codec in HEIF file format)
      • JPEG XR
      • JPEG XL[17]
      • HSP, CTA 2072 HDR Still Photo Interface (a format used by Panasonic cameras for photo capture in HDR with the HLG transfer function)[18]
  • Formats that are only used for storage purpose, such as:

Transmission to displays

Main article: Engineering:High-dynamic-range video

High dynamic range (HDR) is also the common name of a technology allowing to transmit high dynamic range videos and images to compatible displays. That technology also improves other aspects of transmitted images, such as color gamut.

In this context,

  • HDR displays refers to displays compatible with that technology.
  • HDR formats refers to formats such as HDR10, HDR10+, Dolby Vision and HLG.
  • HDR video refers to a video encoded in an HDR format. Thoses HDR video have a greater bit depth, luminance and color volume than standard dynamic range (SDR) video which uses a conventional gamma curve.[22]

On January 4, 2016, the Ultra HD Alliance announced their certification requirements for an HDR display.[23][24] The HDR display must have either a peak brightness of over 1000 cd/m2 and a black level less than 0.05 cd/m2 (a contrast ratio of at least 20,000:1) or a peak brightness of over 540 cd/m2 and a black level less than 0.0005 cd/m2 (a contrast ratio of at least 1,080,000:1).[23][24] The two options allow for different types of HDR displays such as LCD and OLED.[24]

Some options to use HDR transfer functions that better match the human visual system other than a conventional gamma curve include the HLG and perceptual quantizer (PQ).[22][25][26] HLG and PQ require a bit depth of 10-bits per sample.[22][25]

Display

See also: Engineering:History of display technology, Backlight § Backlight dimming, OLED, and High-dynamic-range television

The dynamic range of a display refers to range of luminosity the display can reproduce, from the black level to its peak brightness. The contrast of a display refers to the ratio between the luminance of the brightest white and the darkest black that a monitor can produce.[27] Multiple technologies allowed to increase the dynamic range of displays.

In May 2003, BrightSide Technologies demonstrated the first HDR display at the Display Week Symposium of the Society for Information Display. The display used an array of individually-controlled LEDs behind a conventional LCD panel in a configuration known as "local dimming". BrightSide later introduced a variety of related display and video technologies enabling visualization of HDR content.[28] In April 2007, BrightSide Technologies was acquired by Dolby Laboratories.[29]


Realtime HDR vision

Mann's HDR (high-dynamic-range) welding helmet augments the image in dark areas and diminishes it in bright areas, thus implementing computer-mediated reality.

In the 1970s and 1980s, Steve Mann invented the Generation-1 and Generation-2 "Digital Eye Glass" as a vision aid to help people see better with some versions being built into welding helmets for HDR vision.[30][31][32][33][34][35]

Non-imaging

Audio

In Audio, the term high dynamic range means there is a lot of variation in the levels of the sound. Here, the dynamic range refers to the range between the highest volume and lowest volume of the sound.

XDR (audio) is used to provide higher-quality audio when using microphone sound systems or recording onto cassette tapes.

HDR Audio is a dynamic mixing technique used in EA Digital Illusions CE Frostbite Engine to allow relatively louder sounds to drown out softer sounds.[36]

Dynamic range compression is a set of techniques used in audio recording and communication to put high-dynamic-range material through channels or media of lower dynamic range. Optionally, dynamic range expansion is used to restore the original high dynamic range on playback.

Radio

In radio, high dynamic range is important especially when there are potentially interfering signals. Measures such as spurious-free dynamic range are used to quantify the dynamic range of various system components such as frequency synthesizers. HDR concepts are important in both conventional and software-defined radio design.

Instrumentation

In many fields, instruments need to have a very high dynamic range. For example, in seismology, HDR accelerometers are needed, as in the ICEARRAY instruments.

See also

References

  1. ↑ Robertson, Mark A.; Borman, Sean; Stevenson, Robert L. (April 2003). "Estimation-theoretic approach to dynamic range enhancement using multiple exposures". Journal of Electronic Imaging 12 (2): 220, right column, line 26219–228. doi:10.1117/1.1557695. Bibcode: 2003JEI....12..219R. "The first report of digitally combining multiple pictures of the same scene to improve dynamic range appears to be Mann". 
  2. ↑ Dufaux, Frédéric; Le Callet, Patrick; Mantiuk, Rafal; Mrak, Marta (2016). High Dynamic Range Video – From Acquisition to Display and Applications. Elsevier. doi:10.1016/C2014-0-03232-7. ISBN 978-0-08-100412-8. https://www.sciencedirect.com/book/9780081004128/high-dynamic-range-video. 
  3. ↑ "Compositing Multiple Pictures of the Same Scene", by Steve Mann, in IS&T's 46th Annual Conference, Cambridge, Massachusetts, May 9–14, 1993
  4. ↑ Reinhard, Erik; Ward, Greg; Pattanaik, Sumanta; Debevec, Paul (2005). High dynamic range imaging: acquisition, display, and image-based lighting. Amsterdam: Elsevier/Morgan Kaufmann. p. 7. ISBN 978-0-12-585263-0. "Images that store a depiction of the scene in a range of intensities commensurate with the scene are what we call HDR, or "radiance maps". On the other hand, we call images suitable for display with current display technology LDR." 
  5. ↑ Arnaud Darmont (2012). High Dynamic Range Imaging: Sensors and Architectures (First ed.). SPIE press. ISBN 978-0-81948-830-5. http://spie.org/x648.html?product_id=903927. 
  6. ↑ Simon Green and Cem Cebenoyan (2004). "High Dynamic Range Rendering (on the GeForce 6800)". GeForce 6 Series. nVidia. p. 3. http://download.nvidia.com/developer/presentations/2004/6800_Leagues/6800_Leagues_HDR.pdf. 
  7. ↑ Chan, Eric (Adobe); Hubel, Paul M. (Apple) (January 2023). "Embedded Gain Maps for Adaptive Display of High Dynamic Range Images". Stereoscopic Displays and Applications XXXIV. https://www.youtube.com/watch?v=HBVBLV9KZNI. 
  8. ↑ Benz, Greg (2024-09-27). "What do Apple's latest updates mean for HDR photography?" (in en-US). https://gregbenzphotography.com/hdr-photos/apple-macos-ios-hdr-iso-gain-map-21496-1/. 
  9. ↑ 9.0 9.1 Rahman, Mishaal (2024-10-29). "Google and Apple are making HDR photos work better on Android and iOS" (in en). https://www.androidauthority.com/google-apple-hdr-photo-standard-3495035/. 
  10. ↑ 10.0 10.1 Benz, Greg (2022-08-24). "Create and edit true HDR (High Dynamic Range) images" (in en-US). https://gregbenzphotography.com/hdr/. 
  11. ↑ 11.0 11.1 Chan, Eric. "Gain Maps, Version 1.0 draft 14". https://helpx.adobe.com/content/dam/help/en/camera-raw/using/gain-map/jcr_content/root/content/flex/items/position/position-par/table/row-io13dug-column-4a63daf/download_section/download-1/Gain_Map_1_0d14.pdf. 
  12. ↑ 12.0 12.1 "Ultra HDR Image Format v1.1" (in en). https://developer.android.com/guide/topics/media/platform/hdr-image-format. 
  13. ↑ Romero, Andrew (2024-04-02). "Samsung's Super HDR is not coming to older Galaxy devices". https://9to5google.com/2024/04/02/samsungs-super-hdr-on-older-galaxy/. 
  14. ↑ Benz, Greg (2022-08-24). "HDR - AVIF: the future of HDR" (in en-US). https://gregbenzphotography.com/hdr/. 
  15. ↑ Benz, Greg (2022-08-24). "HDR Standards" (in en-US). https://gregbenzphotography.com/hdr/#standards. 
  16. ↑ "Apple's "EDR" Brings High Dynamic Range to Non-HDR Displays" (in en-US). 2020-12-04. https://prolost.com/blog/edr. 
  17. ↑ "ISO/IEC JTC 1/SC29/WG1". 9–15 April 2018. https://jpeg.org/downloads/jpegxl/jpegxl-cfp.pdf. 
  18. ↑ "Press Release - A New Hybrid Full-Frame Mirrorless Camera, the LUMIX S5 Featuring Exceptional Image Quality in High Sensitivity Photo/Video And Stunning Mobility". https://www.panasonic.com/content/dam/Panasonic/Global/Learn-More/Lumix-s/DC-S5_PressRelease.pdf. 
  19. ↑ "Industrial Light & Magic Releases Proprietary Extended Dynamic Range Image File Format OpenEXR to Open Source Community" (PDF) (Press release). 22 January 2003. Archived from the original (PDF) on 21 July 2017. Retrieved 27 July 2016.
  20. ↑ 20.0 20.1 "Main OpenEXR web site". http://www.openexr.com. 
  21. ↑ 21.0 21.1 "ACES". Academy of Motion Picture Arts and Sciences. http://www.oscars.org/science-technology/sci-tech-projects/aces. 
  22. ↑ 22.0 22.1 22.2 T. Borer; A. Cotton. "A "Display Independent" High Dynamic Range Television System". BBC. https://downloads.bbc.co.uk/rd/pubs/whp/whp-pdf-files/WHP309.pdf. 
  23. ↑ 23.0 23.1 "UHD Alliance Defines Premium Home Entertainment Experience". Business Wire. 2016-01-04. http://www.businesswire.com/news/home/20160104006605/en/UHD-Alliance-Defines-Premium-Home-Entertainment-Experience. 
  24. ↑ 24.0 24.1 24.2 "What is UHD Alliance Premium Certified?". CNET. 2016-03-11. http://www.cnet.com/news/what-is-uhd-alliance-premium-certified/. 
  25. ↑ 25.0 25.1 Adam Wilt (2014-02-20). "HPA Tech Retreat 2014 – Day 4". DV Info Net. http://www.dvinfo.net/article/trip_reports/hpa-tech-retreat-2014-day-4.html. 
  26. ↑ Bryant Frazer (2015-06-09). "Colorist Stephen Nakamura on Grading Tomorrowland in HDR". studiodaily. http://www.studiodaily.com/2015/06/colorist-stephen-nakamura-grading-tomorrowland-dolby-vision/. 
  27. ↑ "Our Monitor Picture Quality Tests: Contrast" (in en-US). https://www.rtings.com/monitor/tests/picture-quality/contrast-ratio. 
  28. ↑ Seetzen, Helge; Whitehead, Lorne A.; Ward, Greg (2003). "54.2: A High Dynamic Range Display Using Low and High Resolution Modulators" (in en). SID Symposium Digest of Technical Papers 34 (1): 1450–1453. doi:10.1889/1.1832558. ISSN 2168-0159. https://sid.onlinelibrary.wiley.com/doi/abs/10.1889/1.1832558. 
  29. ↑ "Dolby Laboratories (DLB) Acquires BrightSide for $28M". https://www.streetinsider.com/Mergers+and+Acquisitions/Dolby+Laboratories+%28DLB%29+Acquires+BrightSide+for+%2428M/1712967.html. .
  30. ↑ Quantigraphic camera promises HDR eyesight from Father of AR, by Chris Davies, SlashGear, Sep 12th 2012
  31. ↑ Ackerman, Elise (31 Dec 2012). "Why Smart Glasses Might Not Make You Smarter". IEEE Spectrum. https://spectrum.ieee.org/why-smart-glasses-might-not-make-you-smarter. 
  32. ↑ Mann, Steve (February 1997). "Wearable Computing: A First Step Toward Personal Imaging". IEEE Computer 30 (2): 25–32. doi:10.1109/2.566147. http://wearcam.org/ieeecomputer/r2025.htm. 
  33. ↑ "A magical welding helmet that lets you see the world in HDR–in real-time". http://moteandbeam.net/eyetap-HDR-welding. 
  34. ↑ Mann, Steve (Fall 2012). "Through the Glass, Lightly". IEEE Technology and Society Magazine 31 (3): 10–14. doi:10.1109/MTS.2012.2216592. Bibcode: 2012ITSMg..31c..10M. http://wearcam.org/glassage. 
  35. ↑ "'GlassEyes': The Theory of EyeTap Digital Eye Glass, supplemental material for 'Through the Glass, Lightly'". IEEE Technology and Society Magazine 31 (3). Fall 2012. http://wearcam.org/glass.pdf. 
  36. ↑ EA DICE/Electronic Arts (2007). "Battlefield: Bad Company - Frostbite Engine Trailer" (video). Electronic Arts. https://www.youtube.com/watch?v=iey04xp2lUc. 



Retrieved from "https://handwiki.org/wiki/index.php?title=Engineering:High_dynamic_range&oldid=3871022"