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HDTV blur

HDTV blur

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HDTV blur is a common term used to describe a number of different artifacts on modern consumer high-definition television
High-definition television
High-definition television is video that has resolution substantially higher than that of traditional television systems . HDTV has one or two million pixels per frame, roughly five times that of SD...

 sets.

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.
  • Pixel response time
    Response time
    In technology, response time is the time a system or functional unit takes to react to a given input.- Data processing :In data processing, the response time perceived by the end user is the interval between the instant at which an operator at a terminal enters a request for a response from a...

     on LCD displays (blur in the color response of the active pixel)
  • Lower camera shutter speed
    Shutter speed
    In photography, shutter speed is a common term used to discuss exposure time, the effective length of time a camera's shutter is open....

    s common in Hollywood production films (blur in the content of the film)
  • Blur from eye tracking fast moving objects on sample-and-hold LCD, plasma, or microdisplay.
  • Resolution resampling
    Resampling
    Resampling may refer to:* Resampling , several related audio processes* Resampling , resampling methods in statistics* Resampling , scaling of bitmap images* Sample rate conversion-See also:* Downsampling* Upsampling...

     (blur due to resizing image to fit the native resolution of the HDTV)
  • Blur due to 3:2 pulldown and/or motion-speed irregularities in framerate conversions from film to video
  • High and/or lossy compression present in almost all digital video streams

Causes


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.

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. However, even when this response time is achieved or surpassed, motion blur can still occur because of the least understood blur effect: eye tracking.

LCDs often have a greater motion blur effect because their pixels remain lit, unlike CRT phosphors that merely flash briefly. Reducing the time an LCD pixel is lit reduces motion blur due to eye tracking by decreasing the time the backlit pixels are on. However, an instant strobe is required to completely eliminate the retinal blurring.

Strobing backlight

  • Philips
    Philips
    Koninklijke Philips Electronics N.V. , more commonly known as Philips, is a multinational Dutch electronics company....

     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.

  • Samsung
    Samsung
    The Samsung Group is a South Korean multinational conglomerate corporation headquartered in Samsung Town, Seoul, South Korea...

     developed "LED Motion Plus" strobed backlighting, which is available on the "Samsung 81 Series" LCD screens as of August 2007.

  • BenQ
    BenQ
    BenQ Corporation is a Taiwanese multi-national company that sells and markets consumer electronics, computing and communications devices under the "BenQ" brand name, which stands for the company slogan Bringing Enjoyment and Quality to life .- Company :BenQ sells and markets technology products,...

     developed SPD (Simulated Pulse Drive), also more commonly known as "black frame insertion", and claim that their images are as stable and clear as CRTs. This is conceptually similar to a strobing backlight.

100 Hz +


Some displays that run at 100 Hz or more add additional technology to address blurring issues. Motion interpolation
Motion interpolation
Motion interpolation is a form of video processing in which intermediate animation frames are generated between existing ones, in an attempt to make animation more fluid.-HDTV:...

 can cut the amount of blur while adding to the latency by inserting extra synthesized in-between frames. Some LCD TVs supplement the standard 50/60 Hz signal by interpolating
Motion interpolation
Motion interpolation is a form of video processing in which intermediate animation frames are generated between existing ones, in an attempt to make animation more fluid.-HDTV:...

 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. The effect of this technology is most noticeable when watching material that was originally shot on 35mm film, in which case the typical film judder can be reduced, at the cost of introducing small visual artifacts
Digital artifact
A digital artifact is any undesired alteration in data introduced in a digital process by an involved technique and/or technology.-Possible causes:...

. Film that is viewed with this kind of processing can have a smoother look, appearing more like it was shot on video, in contrast to the typical look of film.

Motion interpolation technology generally may be added to TVs in PAL/SECAM countries if the TV refreshes at 100 Hz and in NTSC countries if the TV refreshes at 120 Hz. 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 due to gamers' sensitivity to lag even in the 200ms range, it is often better to turn off all video enhancement effects for video games.

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 pulldown from 24 frame/s video is possible meaning all frames are on screen for the same 42 milliseconds. This eliminates the jerky effect associated with 3:2 pulldown called 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 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. (for specific models, see list of displays that support pulldown at multiples of the original frame rate.) PAL countries speed the 24 frame/s film speed by 4% to obtain 25 frame/s, therefore movies in the PAL format are completely free of Telecine judder effects.

Recently, so-called 240 Hz have become available. There are two classes of sets that claim 240 Hz. In the better class, Samsung and Sony both create 3 additional frames of data to supplement the original 60 Hz signal. Other manufacturers to this date who also claim 240 Hz are merely applying an image strobe to a more traditional 120 Hz approach and calling it 240 Hz. Both Samsung and Sony allow for strobing the backlight, but do not market the product with an inflated frequency count. The Sony and Samsung 240 Hz sets also provide for viewing content in 3D, which benefits from the same base technologies of strobing backlights and fast LCD response times.

Manufacturer Terminology:
  • JVC
    JVC
    , usually referred to as JVC, is a Japanese international consumer and professional electronics corporation based in Yokohama, Japan which was founded in 1927...

     calls their 100 Hz + technology "Clear Motion Drive" and "Clear Motion Drive II 100/120HZ".
  • LG
    LG
    LG may refer to:*LG Corp., a South Korean electronics and petrochemicals conglomerate*LG Electronics, an affiliate of the South Korean LG Group which produces electronic products* Lawrence Graham, a London headquartered firm of business lawyers...

     calls their 100 Hz + technology "TruMotion". In the U.S., 120 Hz is called "Real Cinema 24".
  • Mitsubishi
    Mitsubishi
    The Mitsubishi Group , Mitsubishi Group of Companies, or Mitsubishi Companies is a Japanese multinational conglomerate company that consists of a range of autonomous businesses which share the Mitsubishi brand, trademark and legacy...

     calls their 100 Hz + technology "Smooth120Hz".
  • Samsung
    Samsung
    The Samsung Group is a South Korean multinational conglomerate corporation headquartered in Samsung Town, Seoul, South Korea...

     calls their 100 Hz + technology AMP "Auto Motion Plus".
  • Sony
    Sony
    , commonly referred to as Sony, is a Japanese multinational conglomerate corporation headquartered in Minato, Tokyo, Japan and the world's fifth largest media conglomerate measured by revenues....

     calls their 100 Hz + technology "Motionflow".
  • Toshiba
    Toshiba
    is a multinational electronics and electrical equipment corporation headquartered in Tokyo, Japan. It is a diversified manufacturer and marketer of electrical products, spanning information & communications equipment and systems, Internet-based solutions and services, electronic components and...

     calls their 100 Hz + technology "Clear Frame".
  • Insignia
    Insignia
    Insignia or insigne pl -nia or -nias : a symbol or token of personal power, status or office, or of an official body of government or jurisdiction...

     (Best Buy/Future Shop) house brand calls their 120 Hz + technology DCM Plus, for Digital Clear Motion.
  • Sharp
    Sharp
    Sharp or SHARP may refer to:*Sharp *Sharp , a flour made from hard wheat*Sharp , Canadian magazine*Sharp Daily, a free newspaper published in Taiwan and Hong Kong*Sharp...

     calls their technology AquaMoton 240hz.

Laser TV


Laser TV
Laser TV
Laser color television , or Laser color video display utilizes two or more individually modulated optical rays of different colors to produce a combined spot that is scanned and projected across the image plane by a polygon-mirror system or less effectively by optoelectronic means to produce a...

 has the potential to eliminate double imaging and motion artifacts by utilizing a scanning architecture similar to the way that a CRT works. Laser TV
Laser TV
Laser color television , or Laser color video display utilizes two or more individually modulated optical rays of different colors to produce a combined spot that is scanned and projected across the image plane by a polygon-mirror system or less effectively by optoelectronic means to produce a...

 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, 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.

See also


  • Telecine
    Telecine
    Telecine is transferring motion picture film into video and is performed in a color suite. The term is also used to refer to the equipment used in the post-production process....

     (with description of telecine judder).
  • Input lag
    Input lag
    Display lag is a phenomenon associated with some types of LCD displays, and nearly all types of HDTVs, that refers to latency, or lag measured by the difference between the time a signal is input into a display and the time it is shown by the display. This lag time has been measured as high as...

  • Interlacing
  • Deinterlacing
    Deinterlacing
    Deinterlacing is the process of converting interlaced video, such as common analog television signals or 1080i format HDTV signals, into a non-interlaced form....

  • HDTV
  • Refresh rate
    Refresh rate
    The refresh rate is the number of times in a second that a display hardware draws the data...

  • Motion interpolation
    Motion interpolation
    Motion interpolation is a form of video processing in which intermediate animation frames are generated between existing ones, in an attempt to make animation more fluid.-HDTV:...


External links