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Line 1: {{short description\|Blurriness due to image persistence when tracking objects}} ~~'''HDTV blur''' is a common term used to describe a number of different artifacts on modern consumer high-definition television sets.~~ {{About\|display motion blur\|motion blur in recorded media\|motion blur (media)}} [[File:Soccer ball (blur).png\|thumb\|Depiction of eye-tracking motion blur]] [[File:Display motion blur graph.png\|thumb\|Discrepancy in eye tracking on common sample-and-hold type displays.]] In [[Flat-panel display\|modern displays]], '''motion blur''' is an unwanted [[visual artifact\|artifact]] caused primarily by: The following factors are generally the primary or secondary causes of [[HDTV]] blur; in some cases more than one of these factors may be in play at the studio or receiver end of the transmission chain. # [[Persistence of vision\|Retinal blur]] resulting from your eyes ''continuously'' tracking ''discrete'' movement. While your eyes move, the object you're tracking remains stationary throughout each frame, causing it to "smear". This does not happen in real life where both move continuously. * Pixel [[response time]] on LCD displays (blur in the color response of the active pixel) # Slow pixel response times, which lead to visible ghosting or smearing. * Slower camera [[shutter speed]]s common in Hollywood production films (blur in the [[HDV]] content of the film) * Blur from eye tracking fast moving objects on [[sample-and-hold]] LCD, plasma, or microdisplay.<ref>[http://www.poynton.com/PDFs/Motion_portrayal.pdf Charles Poynton is an authority on artifacts related to HDTV, and discusses motion artifacts succinctly and specifically]</ref> * Resolution [[resampling]] (blur due to resizing image to fit the native resolution of the HDTV) * Blur due to [[Telecine#2:3_pulldown\|3:2 pulldown]] and/or motion-speed irregularities in framerate conversions from film to video * Computer generated [[motion blur]] introduced by [[video games]]<ref>[http://www.projectoffset.com Computer Game Engine that makes use of Motion Blur Effects]</ref> The faster the motion, the more pronounced the effect is. ~~==Causes==~~ == Cause == ~~It is common for observers to confuse or misunderstand the source of blurring on HDTV sets. There are many different possible causes, many of them being possible simultaneously.~~ Displays work by rapidly showing frames, each one slightly different from the previous, thereby creating the illusion of movement. Let's take a normal computer monitor with a resolution of 1920×1080 and a refreshrate of 60 Hz. If an object were to move across the display in 2 seconds, there would be 60×2 = 120 "steps", each one [[Translation (geometry)\|translated]] by 1920÷120 = 16 pixels. Your eyes, however, would not start and stop, over and over again to track the object, quickly moving the [[Fovea centralis\|fovea]] to the "new" position of the object for 1000÷60 ≈ 16 milliseconds, only to do it again and again. Instead, your gaze would move across the display in a fluid motion, following the approximate ___location of said object. Because your eyes rotate to track something that doesn't actually move in a smooth, continuous motion, the image gets "smeared" across the [[retina]]. This mismatch is what causes motion blur, and explains why it doesn't occur when tracking physical objects; unlike the simulated motion on displays, real motion is actually continuous, whereas on a display, objects travel in a discrete steps. The experienced motion blur can be approximated purely as a function of persistence, similar to the [[shutter speed]] when taking pictures, because motion wise, it is actually the exact same thing, just from opposite frames of reference. == Reducing motion blur == Pixel response times need to be below 16.67 milliseconds in order to fully represent the bandwidth of color changes necessary for [[60 Hz]] video. But achieving faster than 16.67 does not eliminate motion blur because of the least understood of all of these blur effects is that due to eye tracking. Motion clarity can be improved by decreasing the persistence, which is the amount of time the image is displayed for. Manufacturers use various names for their motion clarity enhancing technologies. Nvidia's implementation is called ULMB, Asus' ELMB, and BenQ Zowie uses DyAc and DyAc+. LG refers to black frame insertion on their OLED TV's as "OLED Motion (Pro)". The "pro" moniker denotes that BFI at 120 Hz is supported, as opposed to being limited to 60. === Black frame insertion === LCDs often have a greater motion blur effect because the pixel in an LCD remains lit unlike the CRT phosphors that merely strobe for a very brief period of time. Reducing the time an LCD is lit has been shown to reduce motion blur due to eye tracking by decreasing the time period the backlit pixels are on.<ref>[http://adsabs.harvard.edu/abs/2006SPIE.6057..213F Publishing from February 2006 from Sharp discussing LED flashing to reduce temporal retinal blur effects with decreasing on-time duty cycle for the backlight.]</ref> However, an instant strobe is required to completely eliminate the retinal blurring. The key to reducing motion blur lies in decreasing the time the pixel stay illuminated. On [[liquid-crystal display]]s, this can be accomplished by [[#Backlight_strobing\|strobing the backlight]], whereas on [[OLED]]s, this must be done by rapidly turning the pixels on and off, made possible by the fact that OLEDs have response times far shorter than those of LCDs. OLED TVs released 2020 & 2021 utilizing LG's WOLED panels feature black frame insertion at 120 Hz, with a duty cycle as low as 38%, resulting in a mere 3.2 ms of persistence. Due to the BFI, the experienced motion blur is comparable to that of a regular sample-and-hold OLED display running at roughly 310 Hz. <ref>[http://www.r2d.com.tw/index.php?lang=en&page=mprt&menu=service&q=q002#q002 How human eyes sense the motion blur on moving object of LCD panel?]</ref><ref>[http://www.r2d.com.tw/index.php?lang=en&page=mprt&menu=service&q=q003#q003 Three methods of classic MPRT measurement equipments.]</ref><ref>[http://orderedwords.net/badgers/Correlation%20between%20Perceived%20Motion%20Blur%20and%20MPRTMeasurement.pdf Another PDF describing MPRT]</ref> === Backlight strobing === ~~==Fixes==~~ By quickly turning the backlight on and off ("strobing"), the image appears for a shorter amount of time. This reduction in persistence is what reduces motion blur. Different manufacturers use many names for their strobed backlight technologies for reducing motion blur on sample-and-hold LCDs. ~~===Strobing backlight===~~ * [[Philips]] created Aptura also known as ClearLCD to strobe the backlight in order to reduce the sample time and thus the retinal blurring due to sample-and-hold.<ref>[http://www.lighting.philips.com/gl_en/news/content_homepage/PS4-13PhilipsclearLCD_5.pdf Philips brochure advertising Aptura backlighting that reduces retinal blurring significantly]</ref><ref>[http://www.hometheatermag.com/lcds/1206philips42pf/ Review of a philips Aptura set that discusses Aptura briefly]</ref> ~~{{main\|~~===Motion interpolation}}===▼ * [[Samsung]] developed "LED Motion Plus" strobed backlighting and is available on the "Samsung 81 Series" LCD screens as of August 2007.<ref>[http://www.abtelectronics.com/images/products/PDF_Files/Samsung_81_Series_om.pdf User manual for Samsung 81 Series TVs with LED Motion Plus technology]</ref> {{main\|Motion interpolation}} Some displays use [[motion interpolation]] to run at a higher [[refresh rate]], such as 100 Hz or 120 Hz to reduce motion blur. Motion interpolation generates artificial in-between frames that are inserted between the real frames. The advantage is reduced motion blur on sample-and-hold displays such as LCD. * [[BenQ]] developed SPD (Simulated Pulse Drive) also more commonly known as "black frame insertion" and they claim that their images are as stable and clear as CRT's.<ref>[http://benq.com/products/LCD/?product=997 BenQ described "black frame insertion" on FP241VW monitor release in 2006]</ref><ref>[http://benq.com/products/LCD/?product=1270 BenQ describes "Simulated Pulse Drive" which seems to be the same technology but renamed for their newer monitor line announced December 2007]</ref> This is conceptually similar to a strobing backlight. There can be side-effects, including the [[soap opera effect]] if interpolation is enabled while watching movies (24 fps material). Motion interpolation also adds [[input lag]], which makes it undesirable for interactive activity such as computers and video games.<ref>[https://games.gearlive.com/index.php/playfeed/article/resolving-hdtv-lag-in-games-06142215 Resolving latency issues in HDTV video games]</ref> ~~===100 Hz +===~~ ▲{{main\|Motion interpolation}} Some displays cut the amount of blur while adding to the latency by inserting in-between frames. For instance some LCD TVs supplement the standard 50/60 Hz signal by [[Motion interpolation\|interpolating]] an extra frame between every pair of frames in the signal so the display runs at 100 Hz or 120 Hz depending on which country you live in. PAL/SECAM countries adopt 100 Hz and NTSC countries typically adopt 120 Hz.<ref>[http://www.jvc.com/press/index.jsp?item=513&pageID=1 JVC Makes first 120 Hz set to cut retinal blur in half]</ref> It's notable that this solution is adequate for movies (which must have blur to begin with to solve double imaging problems with higher shutter speeds on film) but not for video games, which require less than 1 frame or 16.66 ms of latency for optimal playability.{{Fact\|date=August 2007}}<ref>[http://games.gearlive.com/index.php/playfeed/article/resolving-hdtv-lag-in-games-06142215 Resolving latency issues in HDTV video games]</ref> Recently, 240 Hz interpolation have become available, along with displays that claim an equivalence to 480 Hz or 960 Hz. Some manufacturers use a different terminology such as Samsung's "Clear Motion Rate 960"<ref name=cmr>[https://www.samsung.com/us/article/clear-motion-rate-a-new-standard-for-motion-clarity Samsung Clear Motion Rate, including the use of a strobed backlight]</ref> instead of "Hz". This avoids incorrect usage of the "Hz" terminology, due to multiple motion blur reduction technologies in use, including both motion interpolation and strobed backlights. One possible advantage of a 100 Hz + display is superior conversion of the standard 24 frame/s film speed. Usually movies and other film sources in NTSC are converted for home viewing using what is called [[3:2 pulldown]] which uses 4 frames from the original to create 5 (interlaced) frames in the output. As a result [[3:2 pulldown]] shows odd frames for 50 milliseconds and even frames for 33 milliseconds. At 120 Hz 5:5 [[3:2 pulldown\|pulldown]] from 24 frame/s video is possible<ref>[http://www.patentstorm.us/patents/6111610-claims.html Patent for 5:5 pulldown]</ref> meaning all frames are on screen for the same 42 milliseconds. This eliminates the jerky effect associated with 3:2 pulldown called [[3:2 pulldown#Telecine_judder\|telecine judder]]. However, to use 5:5 pulldown instead of the normal 3:2 pulldown requires either support for 24 frame/s output like 1080p/24 from the DVD/HD DVD/Blu-ray Disc player or the use of [[Telecine#Reverse_telecine_.28a.k.a._IVTC.2Finverse_telecine.29\|reverse telecine]] to remove the standard 3:2 pulldown. Some TVs (particularly plasma models) do 3:3 pulldown at 72 Hz or 4:4 at 96 Hz.<ref>[http://www.pioneerelectronics.ca/pna/plasma/whyplasma/article/page/0,,32171715_293250188,00.html Sets that support 3:3 pulldown at 72 Hz or 4:4 at 96 Hz]</ref> (for specific models, see [http://forum.blu-ray.com/showthread.php?t=5155 list of displays that support pulldown at multiples of the original frame rate].) PAL countries speed the 24 fps film speed by 4% to obtain 25 fps, therefore movies in the PAL format are completely free of Telecine judder effects. As a result, 100 Hz televisions do not suffer from telecine judder as 120 Hz models do. Manufacturer Terminology: * [[JVC]] ~~calls their 100 Hz + technology~~uses "Clear Motion Drive~~" and "Clear Motion Drive II 100/120HZ~~".<ref>[~~http~~https://~~www~~support.jvc~~-asia~~.com/~~main~~consumer/~~lcd_asia/feat2~~product.~~html~~jsp?archive=true&pathId=81&modelId=MODL028398 JVC's \|Clear ~~LCD~~Motion ~~Televisions<!--~~Drive ~~Bot generated title -->~~terminology]</ref> * [[LG]] uses "TruMotion".<ref>[https://www.lg.com/ca_en/tvs/lg-47CS570-lcd-tv LG's TruMotion terminology]</ref> * [[Samsung]] uses "Auto Motion Plus" (AMP),<ref>[https://www.samsung.com/au/news/newsRead.do?news_group=productnews&news_type=consumerproduct&news_ctgry=tv&news_seq=6452&search_keyword=&from_dt=&to_dt= Samsung's Auto Motion Plus terminology] {{webarchive \|url=https://web.archive.org/web/20080112120500/https://www.samsung.com/au/news/newsRead.do?news_group=productnews&news_type=consumerproduct&news_ctgry=tv&news_seq=6452&search_keyword=&from_dt=&to_dt= \|date=January 12, 2008 }}</ref> "Clear Motion Rate" (CMR), and "Motion Rate". * [[Sony]] uses "Motionflow".<ref>[https://www.sony.com.au/articles/article.jsp?articleId=4016&categoryId=21611 Sony's Motionflow terminology] {{webarchive \|url=https://web.archive.org/web/20081208185824/https://www.sony.com.au/articles/article.jsp?articleId=4016&categoryId=21611 \|date=December 8, 2008 }}</ref> * [[Toshiba]] uses "Clear Frame".<ref>[https://www.bigpicturebigsound.com/Toshiba-46LX177-HDTV-1347.shtml Toshiba's Clear Frame terminology]</ref> * [[Sharp Corporation\|Sharp]] uses "AquoMotion".<ref>[https://m.sharpusa.com/ForHome/HomeEntertainment/LCDTVs/Technology.aspx Sharp's AquoMotion terminology]</ref> * [[Vizio]] uses "Clear Action". ===Laser TV===▼ * [[LG]] calls their 100 Hz + technology "TruMotion". {{Update section\|date=January 2023}} [[Laser TV]] has the potential to eliminate double imaging and motion artifacts by utilizing a scanning architecture similar to the way that a CRT works.<ref>{{Cite web \|url=https://www.es.com/products/displays/ESLaser/architecture.asp \|title=Evans and Southerland use column scanning laser to eliminate motion blur on their high-end laser projection system \|access-date=2007-07-31 \|archive-url=https://web.archive.org/web/20070728112203/https://www.es.com/products/displays/ESLaser/architecture.asp \|archive-date=2007-07-28 \|url-status=dead }}</ref> [[Laser TV]] is generally not yet available from many manufacturers. Claims have been made on television broadcasts such as KRON 4 News' Coverage of Laser TV from October 2006,<ref>[https://www.youtube.com/watch?v=DS6wsJRGqnQ KRON 4 News in Bay Area covers coherent and novalux joint venture laser television project]</ref> but no consumer-grade laser television sets have made any significant improvements in reducing any form of motion artifacts since that time. One recent development in laser display technology has been the phosphor-excited laser, as demonstrated by Prysm's newest displays. These displays currently scan at 240 Hz, but are currently limited to a 60 Hz input. This has the effect of presenting four distinct images when eye tracking a fast-moving object seen from a 60 Hz input source.<ref>{{Cite web \|url=https://www.prysm.com/ \|title=Prsym creates a laser-excited phosphor display marketed towards the advertising market and allows tiling of smaller displays \|access-date=2023-08-13 \|archive-date=2020-08-26 \|archive-url=https://web.archive.org/web/20200826063836/https://www.prysm.com/ \|url-status=dead }}</ref> There has also been Microvision's Laser MEMS Based Pico Projector Pro, which has no display lag, no input lag and no persistence or motion blur.<ref>{{Cite web\|url=https://www.blurbusters.com/laser-displays-are-zero-lag-zero-blur-zero-persistence/\|title = Laser displays are zero lag, zero blur, zero persistence}}</ref> * [[Mitsubishi]] calls their 100 Hz + technology "Smooth120Hz".<ref>[http://www.amazon.com/dp/B0018C7FSO#Smooth_120Hz_Film_Motion Description of Smooth120HZ]</ref> * [[Samsung]] calls their 100 Hz + technology AMP "Auto Motion Plus".<ref>[http://www.samsung.com/au/news/newsRead.do?news_group=productnews&news_type=consumerproduct&news_ctgry=tv&news_seq=6452&search_keyword=&from_dt=&to_dt= SAMSUNG Launches Premium 100Hz F8 LCD Television SAMSUNG<!-- Bot generated title -->]</ref> * [[Sony]] calls their 100 Hz + technology "Motionflow".<ref>[http://www.sony.com.au/articles/article.jsp?articleId=4016&categoryId=21611 Article 4016<!-- Bot generated title -->]</ref> * [[Toshiba]] calls their 100 Hz + technology "Clear Frame".<ref>[http://www.bigpicturebigsound.com/Toshiba-46LX177-HDTV-1347.shtml Toshiba REGZA 46LX177 Cinema Series 46-inch LCD HDTV with 120 Hz Processing: Review by Chris Boylan on BigPictureBigSound<!-- Bot generated title -->]</ref> What they are all doing is the equivalent of "in-betweening" in animation, where the key frames are drawn by the source video and the computer interpolates the frames in between the key frames. If video frame 1 has a man with his hand at waist level and video frame 2 has the same man with his hand a little bit above waist level, then the video processor interpolates a frame between them with the man having his hand half way between the two positions, just as the frame sequence would have looked if it had been captured at 100 + frames-per-second rather than 50/60 fields-per-second. The catch is, the original video frames are still blurred compared to what a true 100 + Fps rate would look like. The in between frames are also synthetic, so there is no guarantee they would actually match what you would have seen at a true 100 Hz + Fps. Basically, all this depends on how good the computer algorithms are at synthetic generation of frames. Despite these issues, the above techniques make a huge visible difference to blur and picture motion, a difference that can easily be noticed by anyone with such a television.{{Fact\|date=January 2009}} ▲===Laser TV=== [[Laser TV]] is reported to eliminate double imaging and motion artifacts by strobing the image similar to the way that a CRT works.<ref>[http://www.es.com/products/displays/ESLaser/architecture.asp Evans and Southerland use column scanning laser to eliminate motion blur on their high-end laser projection system]</ref> [[Laser TV]] is generally not yet available, and the results are not confirmed to solve the problem, but claims have been made on television broadcasts such as KRON 4 News' Coverage of Laser TV from October 2006.<ref>[http://www.youtube.com/watch?v=DS6wsJRGqnQ KRON 4 News in Bay Area covers coherent and novalux joint venture laser television project]</ref> == See also == {{Portal\|Television}} * [[Telecine]] technical description also known as judder. * [[~~Input~~Interlaced ~~lag~~video]] * [[~~Interlace\|Interlacing~~Telecine judder]] * [[~~Deinterlacing~~Soap opera effect]] {{clear}} * [[HDTV]] * [[Refresh Rate]] ==External links==▼ * [http://www.hdtvmagazine.com/articles/2008/01/lcd_specs_playing_with_your_eyes.php Article in HDTV Magazine that does a good job of covering motion blur on LCD panels]▼ * [http://www.iitk.ac.in/asid06/proceedings/papers/TC1_1-I.pdf Link describing cause of motion blur from sample and hold techniques and reduction using LED backlighting]▼ * [http://www.techmind.org/lcd/ Techmind.org: LCD technology and tests]▼ * [http://hometheater.about.com/od/televisionbasics/qt/framevsrefresh.htm \| 1080p and framerates explained] * [http://www.xyhd.tv/2007/09/how-to/how-a-32-pull-down-cadence-works-when-converting-film-to-video-telecine/ Methods for 3:2 Pull Down]▼ * [http://benq.com/products/LCD/?product=839 BenQ monitor that uses strobing to reduce sample-and-hold artifacts due to motion eye tracking]▼ * [http://hcpin.svn.sourceforge.net/viewvc/checkout/hcpin/doc/motion_stress.rar Windows application that demonstrates retinal blur due to sample and hold displays]▼ ==References== {{Reflist}} ▲==External links== * [https://www.tftcentral.co.uk/articles/motion_blur.htm Motion Blur Reduction Backlights] * [https://www.blurbusters.com/faq/lcd-motion-artifacts/ Pursuit camera photography of LCD motion blur] ▲* [~~http~~https://www.hdtvmagazine.com/articles/2008/01/lcd_specs_playing_with_your_eyes.php Article in HDTV Magazine that does a good job of covering motion blur on LCD panels] ▲* [~~http~~https://www.iitk.ac.in/asid06/proceedings/papers/TC1_1-I.pdf Link describing cause of motion blur from sample and hold techniques and reduction using LED backlighting] * [https://www.testufo.com/ TestUFO.com: Motion test animations that also demonstrates display motion blur] ▲* [~~http~~https://www.techmind.org/lcd/ Techmind.org: LCD technology and ~~tests~~stationary test patterns] * [https://www.lifewire.com/video-frame-vs-screen-refresh-rate-1847855 1080p and framerates explained] ▲* [~~http~~https://www.xyhd.tv/2007/09/how-to/how-a-32-pull-down-cadence-works-when-converting-film-to-video-telecine/ Methods for 3:2 Pull Down] ▲* [~~http~~https://web.archive.org/web/20071017010929/https://www.benq.com/products/LCD/?product=839 BenQ monitor that uses strobing to reduce sample-and-hold artifacts due to motion eye tracking] ▲* [~~http~~https://hcpin.svn.sourceforge.net/viewvc/checkout/hcpin/doc/motion_stress.rar Windows application that demonstrates retinal blur due to sample and hold displays]{{Dead link\|date=November 2019 \|bot=InternetArchiveBot \|fix-attempted=yes }} {{Video formats}} {{North American DTV}} [[Category:High-definition television]]