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What does the CMR number on Samsung TVs mean? And how to find out real panel refresh rate?

post #1 of 40
Thread Starter 
What does the CMR number actually mean on Samsung TVs these days?

When I bought my TV three years ago, Samsung simply listed the panel's refresh rate (at the time it could be 60Hz, 120Hz, or 240Hz). So if you got a 120Hz display, you knew it could handle 24Hz inputs without telecining.

But now Samsung's website only has this "CMR" number, which it describes like this:

Clear Motion Rate (CMR) is a combination of advanced backlighting technology, significant improvements in panel response rates and ultra fast image processing.

and it no longer says anything about actual refresh rates.

Now, I'm sure that on the higher-end TVs that have CMRs of 240 all the way to 960, that the underlying panel is doing at least 120Hz. But I wonder if, for example, the lowest-end CMR 120 TV really has a 120Hz panel or if it just has a 60Hz panel and Samsung's marketing is trying to make you think that the image processing, etc. will give you output that looks like you have a 120Hz panel.

Any way to find out what the true, underlying refresh rate of a given Samsung TV is?
post #2 of 40
Sounds to me like it's Samsung's version of motion interpolation technology. Artificial frame insertion to smooth out motion.
post #3 of 40
divide the numbers by two to get the refresh rate:

CMR 120 means 60Hz

CMR 240 means 120Hz

CMR 480 means 240Hz

CMR 960 means ??? (probably still 240Hz or maybe 480Hz)
post #4 of 40
Quote:
Originally Posted by PlasmaPZ80U View Post

divide the numbers by two to get the refresh rate:
CMR 120 means 60Hz
CMR 240 means 120Hz
CMR 480 means 240Hz
CMR 960 means ??? (probably still 240Hz or maybe 480Hz)

not really, i have the ES6580 which has 480 CMR but i know for a fact that the panel is actually a 120hz panel, its not a 240hz panel.. i mean thats what iv read everywhere..
post #5 of 40
caveat emptor
post #6 of 40
Quote:
Originally Posted by Otto Pylot View Post

caveat emptor

+1. Information contained in a firmware or service menu may or may not take into consideration such things as "scanned" or "strobed" back light technology (the Advanced Back Lighting Technology", which is an artificial way of simulating a faster panel refresh rate. So a TV that advertises a 240HZ or 480HZ panel rate may actually be half of the advertized rate.

Tricks of the trade.
post #7 of 40
Quote:
Originally Posted by lamonsasa View Post

not really, i have the ES6580 which has 480 CMR but i know for a fact that the panel is actually a 120hz panel, its not a 240hz panel.. i mean thats what iv read everywhere..

really? then I'm not sure what CMR is in relation to actual panel refresh rate in Hz

I do know for sure that the UNxxEH5000 is CMR 120 and 60Hz AND that the UNxxEH6000 is CMR 240 and 120Hz.

As far as the 6070 and 6030, both are CMR 240 but might only be 60Hz since they lack AMP and someone saw within the service menu that the panel was a 60Hz one and that the 6070 was really a 6030.
post #8 of 40
Quote:
Originally Posted by Otto Pylot View Post

Sounds to me like it's Samsung's version of motion interpolation technology. Artificial frame insertion to smooth out motion.

I agree, but you mean Samsung would resort to some sort of techno double talk? wink.gif

Seriously, the EH6000 series has turned out to be quite the sleeper model for the 2012 year in spite of what some pro negative reviews like even CNET made about it. It is important to note that early release models may not be representative of how a model performs or which of several LCD panels it may use throughout the model year. Many TV buyers passed some of these Samsung units by and concurred with the negative reviews. Now, while the CMR tech may be a bit misleading, all in all the Samsung EH6000 series with S-PVA panel is a fairly high performer just as I pointed out many months back. Some even doubted it was a true back lighted LED ( Direct Lit limited full array).
post #9 of 40
Samsung's explanation of Clear Motion Rate:
http://www.samsung.com/us/article/clear-motion-rate-a-new-standard-for-motion-clarity

CMR is supposed to describe an equivalence (in motion clarity) to a theoretical "X hertz" display (running material at full frame rate, X fps).
Technically, this is supposed to mean equivalence to Hz in terms of motion blur reduction, but without using the Hz terminology. The science/theory is sound, involving a combination of motion interpolation and impulse-driven backlight (scanning backlight).

The formula for Samsung's CMR rating and Sony's XR rating, is most easily interpreted as:

CMR = (interpolated hertz rate) / (percentage of a refresh that's lit up by a single bright backlight flash)

Allow me to explain the formula. Once you are beyond the flicker fusion threshold.... Then from a motion blur perspective:
Scientific papers have shown that motion blur is very comparable between an "X Hertz" sample-and-hold display versus a "1 / X second" impulse-driven display. For example, from a motion-blur perspective (on 60fps full-framerate material), a Samsung CMR 960 display is equivalent to a theoretical 960 Hz interpolated display (sample-and-hold display), and is also equivalent to a 60Hz CRT display that uses 1/960sec phosphor persistence (impulse-driven display). Of course, this is a simplified explanation, and strictly limits to the motion-blur metric, and not other display characteristics. Things are not this simple -- you've got things like pixel persistence, backlight diffusion, CRT phosphor decay, imperfect human eye tracking, etc - that fudges actual benefit to human eyes. Needless to say, motion blur reduction benefits clearly exists even at CMR 960 (well beyond CMR 240 and CMR 480), even though it is a point of diminishing returns. Papers show that most motion blur on newer LCD's are now caused by the LCD trait of sample-and-hold rather than the LCD trait of pixel persistence. (Unlike for older LCD's where the majority of the pixel persistence used to be a significant fraction of the length of one refresh).

What makes this even more complicated is when you *combine* interpolation (e.g. 240Hz) with backlight impulse-driving (black frame insertion, scanning backlight, etc). Theoretically, you could do CMR 960 completely using only motion interpolation (60->960fps) or completely using only impulse-driven backlight (1/960sec flashes). But doing "960" in today's flat panels is not achieved by one method alone, due to technological and practical limitations. Samsung (and Sony's equivalent, Motionflow XR 960, as well as the Elite LCD HDTV, which also has the same "960" equivalence) does it by the following, when configured to the most aggressive motion fludity setting:

How Samsung CMR 960 and Sony XR 960 is achieved
(For present models, and when the display configured to most aggressive motion clarity settings).
- 75% motion blur reduction via 60fps->240fps motion interpolation
- 75% motion blur reduction via 25%:75% bright:dark impulses. (That's why display is very dim)
Total: theoretical 93.75% motion blur reduction at CMR 960 setting.
--> This is consistent with the math (100 - (60Hz / 960Hz)) = 93.75.

That's 240Hz, and the flashes occur 25% of a refresh.
Thus, the formula becomes:
CMR = 240 / (0.25) = 960

So the formula used for Clear Motion Rate (Samsung) and Motionflow XR (Sony), is actually based on known motion science, although the means to get there is somewhat controversially paved. At the bottom line, Hz doesn't really matter much once you stop seeing the flicker (e.g. no 60 Hz CRT flicker) -- it is motion blur that is the biggest issue with flat panels, and there's multiple solutions (impulse-driving and motion-interpolation) to achieve that, as we all already know. Impulse-driving a display (CRT or scanning backlight) is better and lower latency for interactivity and video games, computers, while motion interpolation is useful for non-interactive fast full-framerate action (skiing, NASCAR, hockey, football, red bull air races, etc), while a lot more controversial for 24p material (there are personal preferences, no comment).

IMPORTANT: *real world* motion blur reduction is far less than these ratings, often because of other factors, such as LCD panel behaviours, backlight diffusion (lit backlight leaking into dark parts of panel, etc), imperfect eye tracking, and other effects. It's much like a contrast ratio rating.

References: Research I did for my Scanning Backlight FAQ and Science & References page of my BlurBusters Blog.
Quote:
"Dynamic-Scanning Backlighting Makes LCD TV Come Alive."
by Seyno Sluyterman (InformationDisplay.org, October 2005)

"LCD motion-blur analysis, perception, and reduction using synchronized backlight flashing"
by Xiao-fen Feng (Sharp Labs. of America Inc., February 2006)

"Frame Rate conversion in the HD Era"
by Oliver Erdler (Stuttgart Technology Center, EuTEC, Sony Germany, 2008)
Page 4 has very useful motion blur diagrams, comparing sample-and-hold versus impulse-driven displays.

"Perceptually-motivated Real-time Temporal Upsampling of 3D Content for High-refresh-rate Displays"
by Piotr Didyk, Elmar Eisemann, Tobias Ritschel, Karol Myszkowski, Hans-Peter Seidel (EUROGRAPHICS 2010 by guest editors T. Akenine-Möller and M. Zwicker)
Section "3. Perception of Displays" (and Figure 1) explains how LCD pixel response blur canbe separate from hold-type (eye-tracking) motion blur.

"Flicker Fusion"
by Stephen Macknik, Barrow Neurological Institute (Scholarpedia)
Background information that relates to how flicker becomes a continuous image (applies to CRT and to scanning backlights).

"Temporal Resolution"
by Michael Kalloniatis and Charles Luu, Webvision (University of Utah)
Background information that relates to human vision behavior and how multiple flicker events, over a short interval, blends together.

"Motion portrayal, eye tracking, and emerging display technology"
by Charles Poynton (1996) Although this paper is fairly old, it accurately explains eye tracking effects and how it relates to motion blur.
Note: At ScanningBacklight.com, I am presently doing some research & development towards eliminating disadvantages of a scanning backlight by using a 240 watt LED backlight for a 23" computer monitor -- almost 150 watts per square foot! Running at 5%:95% bright:dark strobes. Also, driven at 120 Hz native refresh, to eliminate flicker. Manufacturers haven't started making ultrahigh-performance scanning backlights yet, due to the insane costs necessary for ultra-bright 150W/sqft backlight needed for ultra-short strobes, necessary to reduce motion blur by 95% similar to a CRT. It's aimed for interactivity/computers/games, something not possible without input lag when using interpolation. I used to design video processors for a living -- In the early 2000's, remember the TAW ROCK, Key Digital LEEZA, Immersive HOLO3DGRAPH -- I made the firmware/software for these scalers. I am also one of the authors of the old dScaler application for HTPC's including its open source 3:2 algorithm. As a result, I gained a great understanding of display technologies in my testing with many displays.
Edited by Mark Rejhon - 10/24/12 at 2:05pm
post #10 of 40
Quote:
Originally Posted by Phase700B View Post

+1. Information contained in a firmware or service menu may or may not take into consideration such things as "scanned" or "strobed" back light technology (the Advanced Back Lighting Technology", which is an artificial way of simulating a faster panel refresh rate. So a TV that advertises a 240HZ or 480HZ panel rate may actually be half of the advertized rate.
Tricks of the trade.
Heads up. Both interpolation and scanning backlight are *artificial*.

Using a scanning backlight is no less artificial than interpolation, if properly done. Many people liked the natural-looking motion in sports on CRT displays. If Samsung applied their CMR rating to an old CRT television, an old CRT television has an approximately CMR 1000 or CMR 2000 because of very short phosphor decay. All a scanning backlight is doing, is gaining the same motion blur reduction benefits that a CRT is able to have, by impulse-driving the display. Let's at least give credit where credit is due -- both Samsung and Sony has stopped using "Hertz" and instead started using "CMR" or "XR" ratings. So it's suddenly stopped being an artifical fake Hertz rating, and finally focuses on actual science of motion blur reduction -- the portion that matters The number is actually mathematically sound, on pre-existing scientific data (and my vision observations appear to agree, too)

Some people would argue that LCD is more artifical than CRT.
But not everyone agrees. It's a matter of perspective, and what frame of reference you're coming from. Dislike flicker? Dislike interpolation? Pick your poison. For some, a properly-designed scanning backlight is a more natural way of motion, especially for computer and gaming. Here's a simplified list of pros and cons for the methods:

Interpolation Method
Advantages: No flicker!
Disadvantages: Artifacts, latency (input lag)

Impulse/Strobe/Scanning Method (CRT style)
Advantages: Low latency, less framerate needed for maximum motion fluidity, suitable for computer and games
Disadvantages: Flicker, Dim Picture (short strobes needs lots of brightness)

Bottom Line -- both interpolation _and_ impulses are artificial human inventions of improving motion.
With different pros and cons for each!

Edited by Mark Rejhon - 10/24/12 at 1:51pm
post #11 of 40
^ ^ ^ Ummm, motion interpolation and panel refresh rate are two different things, though related. I never mentioned motion or frame interpolation.
Quote:
Originally Posted by Phase700B View Post

+1. Information contained in a firmware or service menu may or may not take into consideration such things as "scanned" or "strobed" back light technology (the Advanced Back Lighting Technology", which is an artificial way of simulating a faster panel refresh rate. So a TV that advertises a 240HZ or 480HZ panel rate may actually be half of the advertized rate.
Tricks of the trade.


For instance, a 120HZ LCD panel can produce a non interpolated image so no "artificial" interpolation is taking place. An example is 5:5 pull down of a 24fps source on a native 120HZ display. There are no frames being interpolated in this case, the panel is merely displaying each frame 5 times in order for the 24fps frame rate to match the 120HZ panel refresh rate. 5 times 24fps = 120. In other words, the higher refresh rate makes it possible to use frame interpolation. . . but is not something that automatically happens just because an LCD panel has a 120HZ or 240HZ actual refresh rate. Motion interpolation can usually be turned off on an LCD/LED TV, while panel refresh is inherent in the design of the panel itself.

So a there is nothing inherently artificial being produced by a 60HZ, 120HZ or 240HZ LCD panel. In the case of a scanning back light, granted, a more accurate thing to say is that it is an enhancement of the native refresh rate of the LCD panel. Ergo. . . a tendency to say it is artificial in that respect.

Only when the signal source is stored, analyzed, and additional frames added is interpolation ( artificial ) taking place. This is what is done with Samsung's Auto Motion Plus and other TV makers motion interpolation methods.


It is finally good to see that the use of scanning back light technology is being defined, rather than a TV maker passing it off as a "true" native (ie, 60HZ, 120HZ, 240HZ, etc) hardware specification of the LCD panel itself.
Edited by Phase700B - 10/24/12 at 2:12pm
post #12 of 40
Quote:
Originally Posted by Phase700B View Post

^ ^ ^ Ummm, motion interpolation and panel refresh rate are two different things, though related.
True. _inherently_, no disagreement to what you're saying.

Some people seem to think that one or the other method is more artificial than the other. It's best to withhold such judgements. We can all agree on this -- Motion interpolation technologies and scanning backlight technologies are improving, on different fronts. Alas, these two separate motion-blur-reduction technologies have separate pros and cons, a related topic that often comes up. I had to make necesary simplifications to an otherwise complex subject -- my motion blur discussion is simplified for the "frame rate = refresh rate" situation (whether native or interpolated frame rate).
Quote:
There are no frames being interpolated in this case, the panel is merely displaying each frame 5 times in order for the 24fps frame rate to match the 120HZ panel refresh rate. 5 times 24fps = 120. In other words, the higher refresh rate makes it possible to use frame interpolation. . . but is not something that automatically happens just because an LCD panel has a 120HZ or 240HZ actual refresh rate.
Theoretically, you can also internally interpolate 24fps->120fps then display only every other frame for a 60Hz display. This is conceptually similiar to how some high-end PAL->NTSC conversion systems work; Conceptually, it's similiar to converting 50fps->300fps->60fps. (Note: Processors can internally skip rendering frames that will never be displayed, so you're programmatically only outputting 60 frames with processing mathematically weighted motion vectors, rather than wastefully internally creating the full 300fps) Such motion-compensated PAL->NTSC converters existed long before 120Hz displays. Today, many people see European 50Hz Red Bull Air races converted to 60Hz on a North American HDTV, that re-interpolated it back to 240Hz -- funny situation. Anyway, staying at 60Hz it wouldn't have prevented 24fps->60fps motion-compensated interpolation from happening eventually -- it's just the existence of 120Hz displays just simply made the matter much easier. smile.gif

(An aside: For 24p material, I prefer to skip frame interpolation, and display frames exactly 1/24 of a second, disabling interpolation. However, I do indeed prefer either or both kinds of motion enhancements for full-framerate 60fps material)
Edited by Mark Rejhon - 10/24/12 at 2:28pm
post #13 of 40
It's worth mentioning the CMR rate is tied to the LED Motion Plus feature. With it off, there is no scanning/flashing backlight feature enabled. With it on, the light output goes down by ~50%.

"I measured much better motion resolution (1,080 lines versus about 600) when I turned on the backlight scanning feature, labeled LED Motion Plus. Unfortunately doing so dimmed the picture too much, so I left it off. As usual I had difficulty discerning any difference in motion resolution with program material, as opposed to test patterns, regardless of the setting I chose."

(http://reviews.cnet.com/flat-panel-tvs/samsung-un46eh6000/4505-6482_7-35159621-2.html)

"It's worth mentioning that I didn't engage LED Motion Plus (backlight scanning) because it dimmed the picture considerably. In Movie mode with the mode engaged the TV managed only 27Fl, a good deal short of my target of 40."

(http://forums.cnet.com/7723-19410_102-565020/samsung-un46eh6000-picture-settings/?tag=StickyWin_1339096603800;createThreadPopup)
post #14 of 40
CMR, based on it's description and implementation, has nothing to do with interpolating or "adding" frames that are not part of the original source material. The combination of scanned back lighting and adding artificial interpolated frames to video source material is and has confounded the understanding of which is which. Frame interpolation attempts to smooth or reduce motion blur by adding extra physical frames. Scanned back lighting attempts to reduce motion blur and other motion artifacts by quickly turning of the back light off and back on at a very fast rate, which effectively helps but also reduces light output. Which, also raises the question as to what affect it may have on TV calibration aspects such as gamma, white level, etc. True frame interpolation by adding frames should have no effect on such things.


"How Samsung CMR 960 and Sony XR 960 is achieved
(For present models, and when the display configured to most aggressive motion clarity settings).
- 75% motion blur reduction via 60fps->240fps motion interpolation
- 75% motion blur reduction via 25%:75% bright:dark impulses. (That's why display is very dim)"

The main advantage of CMR (scanned back lighting) would be some motion artifact reduction without increase in input lag time. The trade off is the reduction in picture brightness whether perceived or measurable.

Scanned back light technology is something separate from the previous process of blur and judder reduction, and adding frames (AMP).
post #15 of 40
Quote:
Originally Posted by PlasmaPZ80U View Post

"I measured much better motion resolution (1,080 lines versus about 600) when I turned on the backlight scanning feature, labeled LED Motion Plus. Unfortunately doing so dimmed the picture too much, so I left it off. As usual I had difficulty discerning any difference in motion resolution with program material, as opposed to test patterns, regardless of the setting I chose."
Scanning backlights really benefits fast full-framerate material, such as
- Videogames running at 60fps
- Fast sports with lots of pans, hockey, football, NASCAR, red bull air races, etc.
Quote:
"It's worth mentioning that I didn't engage LED Motion Plus (backlight scanning) because it dimmed the picture considerably. In Movie mode with the mode engaged the TV managed only 27Fl, a good deal short of my target of 40."
It's worth noting that scanning backlight do NOT benefit movies much. It chiefly benefits full-framerate material, to get the maximum smooth effect.
Quote:
Originally Posted by Phase700B View Post

The trade off is the reduction in picture brightness whether perceived or measurable.
It's measurable, with a CRT-compatible Spyder. Measuring the brightness of a scanning backlight is measurable, like the brightness of a CRT is measurable. It's just simple flicker. The picture is dim because scanning backlights turn off the backlight some of the time. So the average brightness is dim. The scanning backlight on the Samsung is flickering at 240Hz (if interpolation turned on), or flickering at 60Hz (if interpolation turned off). The longer the backlight is off during the "off period" of the flicker, the more blur reduction, but the dimmer the picture.

Note: The "dim" picture concerns is why I am designing a 240-watt backlight for a 23" computer monitor (almost 150 watt per square foot), for my Arduino-driven scanning backlight modification of a computer monitor -- I am disassembling a 120Hz gaming computer monitor (Current candidates: Samsung S23A700D, or the Asus VG236H or VG278HE) once my research & development is complete. The overkill wattage will mean the picture can still look normal and bright even with the scanning backlight mode turned on in a very aggressive motion-blur-elimination mode (95% dark, 5% bright). Such an insane level of brightness is not done by actual manufacturers (yet), and additionally the enthusiast gaming computer monitors don't have scanning backlights, since the monitor market had lately been a race-to-bottom in pricing. Average power consumption would still be only 12 watts the 95%-dark mode, and 24-watts in the 90%-dark mode. Keep an eye on my BlurBusters blog.
Edited by Mark Rejhon - 10/25/12 at 7:34am
post #16 of 40
Quote:
Originally Posted by Mark Rejhon View Post

It's measurable, with a CRT-compatible Spyder. Measuring the brightness of a scanning backlight is measurable, like the brightness of a CRT is measurable. It's just simple flicker. The picture is dim because scanning backlights turn off the backlight some of the time. So the average brightness is dim. The scanning backlight on the Samsung is flickering at 240Hz (if interpolation turned on), or flickering at 60Hz (if interpolation turned off). The longer the backlight is off during the "off period" of the flicker, the more blur reduction, but the dimmer the picture.
[

Yes, of course it is measurable. If you can see it, why wouldn't it be measurable?

All of what you are saying has pretty much been said before. And yes, the duty cycle of a lamp on/off period certainly affect over all brightness. Nothing new there either. Most simple wall switch light dimmers essentially do that with either a triac or silicon controlled rectifier controlling the lamp duty cycle and therefore the brightness. Applying it to TV back lighting on a more controlled basis is another application. One would wonder about some electrical interference however from all the hash (electrical noise) created.

At any rate, nothing I would want since we watch mostly movies, and some sports. And on both LCD TVs we have (1 60HZ and 1 120HZ) images of fast moving scenes and objects like in sports or action movies seem just fine. I can see gaming being a different thing with input lag. so that's the main benefit.
post #17 of 40
I have no doubt that strobing the backlight is beneficial--it's doing the same thing the shutter in a motion picture film projector does when it cycles two or three times in each frame of film projected at 24fps. What I have a problem with is that in most cases one cannot tell from the advertising what the true refresh rate of the panel itself is.
post #18 of 40
Quote:
Originally Posted by Steve S View Post

I have no doubt that strobing the backlight is beneficial--it's doing the same thing the shutter in a motion picture film projector does when it cycles two or three times in each frame of film projected at 24fps. What I have a problem with is that in most cases one cannot tell from the advertising what the true refresh rate of the panel itself is.

I agree that Samsung is using this feature to hide the true refresh rates of the LCD panels themselves, which is an annoying and deceptive marketing practice. The CMR 120 sets are definitely only 60Hz but the CMR 240/480/960 sets could be 60Hz, 120Hz, or 240Hz (probably the only way to tell for sure would be to look at the "Type" code in the service menu). Also, since this "LED Motion Plus" feature dims the picture by ~50%, many users will just leave it off in favor of a brighter picture. Also, I have used the feature before with various kinds of source material but I'm not sure I could discern any difference between the two by eye (without test patterns).
post #19 of 40
In the past Samsung panel refresh rates were as follows:

anything below a 6 series was 60hz, 6 series were 120hz, 7 and up were 240hz. This applied to LN ccfl sets and UN led backlit sets.

I have a 47LM6400 LG-a set that's promoted as "Tru-Motion 120". It's actually 60hz with strobing. The "tru-motion" can be adusted in the user menu and from what I've observed is effective at controlling jerkiness during horizontal pans on some source material. I can only assume this is actually varying the duration and/or frequency of the backlight strobing. I've seen no difference in screen brightness when changing this setting or even turning it off. I haven't seen any significant motion blur other than that caused by overcompressed satellite signals--none on BD for example--and am not a fan of the soe effect caused by frame interpolation so am not upset about it not being a "true" 120 hz panel.

I've found with some products, especially electronics and automobiles, specs aren't always indicative of actual performance or my satisfaction with the product.
post #20 of 40
Quote:
Originally Posted by Steve S View Post

I have no doubt that strobing the backlight is beneficial--it's doing the same thing the shutter in a motion picture film projector does when it cycles two or three times in each frame of film projected at 24fps. What I have a problem with is that in most cases one cannot tell from the advertising what the true refresh rate of the panel itself is.
For me, scanning backlights do not benefit movies much. What scanning backlights do is do the equivalent of CRT style impulses, and it really benefits full-framerate material such as 60fps video games, or fast full-framerate material.

When strictly viewing fast full-framerate material (no repeated frames)
Eye tracking based motion blur thickness (of blurred edges) is equal to the distance an object travels on the screen between two consecutive frames. Doubling the framerate means halving this movement step, and thus half motion blur everytime you double the frame rate (interpolation). The same amount perceived motion blur reduction also happens everytime you halve the strobe length too (scanning backlight). Exact same perceived motion blur reduction, mathematically -- when doing things either way. (excluding other quirks of each respective technology, such as motion interpolation artifacts, or scanning backlight flicker). (Citation: Science & References)

Examples (for full-framerate sources, such as 60fps video, or 60fps games), when interpolation is disabled and the scanning backlight is doing all the motion-blur-reduction work.
  • 50% motion blur reduction ("120" operation)
    A strobed backlight doing 50%:50% bright:dark cycle at 60Hz, looks the same (from a motion blur perspective) as 120Hz motion interpolation. (50% motion blur elimination).
  • 75% motion blur reduction ("240" operation)
    A strobed backlight doing 25%:75% bright:dark cycle, looks the same as 240Hz motion interpolation. (75% motion blur elimination). This is done by the best Samsung/Sony displays.
  • Future: 90-95% motion blur reduction
    Necessary to match an average medium-persistence CRT. For future displays with ultrahigh performance scanning backlights that can perform massive motion blur elimination without interpolation (good for near-lag-free operation for computers and games), a strobed backlight displaying 60fps@60Hz signal on a display with a 10%:90% bright:dark impulse cycle, would be equivalent to a theoretical 600fps@600Hz motion interpolation. A 5%:95% bright:dark strobe cycle would look equivalent to interpolated 1200fps@1200Hz operation. (That said, a 5%:95% bright:dark strobe requires a backlight 20 times as powerful! At least 150 watts per square foot). CRT phosphors shine insanely bright (at well over 100 equivalent watt per square foot) but for short periods, and scanning backlights need to match that peak brightness to avoid a dim picture on an ultra-high-performance scanning backlight.

Point of diminishing returns obviously kick in, of course, but it goes well beyond a "120" equivalence. For all practical purposes, to the human vision system, motion blur is equivalently halved everytime you double the framerate, versus everytime you halve the strobe length. (Until you reach limits such as blur inside compressed material, or blur inside slow-shutter camera video, etc -- blur that is still there even when you view on CRT) At this point, we should not care if it's true 600fps or 1200fps -- but rather the motion blur eliminating rating ("CMR 960", "XR 960", etc) is a more honest terminology than "Hz" (whether via fake interpolated frames or artifical black frames), but I can understand that some people want to know how much of the rating is provided by the scanning backlight and how much from interpolation.

Of course, I'm talking about 60fps material (no repeated frames), not 24fps material. The motion blur elimination percentages above, does not apply to 24fps material. (though some people like the projector-style flicker, but that's beyond the scope of this thread). The distinction between interpolation and scanning backlights are quite different when we're not talking about full-framerate material. That's where people who want 48Hz flicker of film projector, may be attracted to a _different_ aspect of a scanning backlight. But that's not the aspect of a scanning backlight that I talk about in my posts. Also see my Scanning Backlight FAQ for more information.
Edited by Mark Rejhon - 10/25/12 at 5:01pm
post #21 of 40
Quote:
Originally Posted by Steve S View Post

I have a 47LM6400 LG-a set that's promoted as "Tru-Motion 120". It's actually 60hz with strobing. The "tru-motion" can be adusted in the user menu and from what I've observed is effective at controlling jerkiness during horizontal pans on some source material. I can only assume this is actually varying the duration and/or frequency of the backlight strobing.
Are you sure the LG is doing it via the strobe approach rather than the interpolation approach? If the LG is doing it via the strobed approach (scanning backlight, black frame insertion, etc) then Tru-Motion 120 would be achieving this with a 60Hz flicker, that's bright 50% of the time and dark 50% of the time. For full-framerate material (60fps), this mathematically results in a 50% motion blur reduction, the same motion blur reduction that frame interpolation from 60Hz to 120Hz does. So that's where the "120" rating comes from.

For a 50%:50% bright:dark scanning backlight, it's easy not to lose much brightness since the peak brightness of the backlight only needs to be double the average screen brightness. The problems begin to occur when trying to achieve a "240" rating or beyond -- with 25%:75% bright:dark scanning backlights like those used by Samsung CMR 960 and Sony Motionflow XR 960 displays, because the peak brightness of the backlight needs to be quadruple the average screen brightness. (Higher-performance scanning/strobed backlights of the future, such as 10%:90% bright:dark, requires a backlight with 10 times as much peak brightness to maintain the same average brightness as without a scanning backlight).

So you see -- the conundrum for scanning/strobed backlights:
The more motion blur reduction, the more powerful the backlight needs to be.
Edited by Mark Rejhon - 10/25/12 at 8:21pm
post #22 of 40
Quote:
Originally Posted by Mark Rejhon View Post

For me, scanning backlights do not benefit movies much. What scanning backlights do is do the equivalent of CRT style impulses . . . ..

I;m not sure your description and analogy comparing strobed back lighting to the scanned line technology of CRTs is accurate. The only "impulses" used in a CRT are those used to hit a particular pixel or spot on the phosphor screen to excite an illuminate it. All CRTs operate in a scanned fashion whereby individual lines of an image are scanned either in an interlaced odd/even fashion or sequentially in a complete progressive scanned frame. This is much different than how a flat panel LCD or plasma works where a whole frame of picture and pixel information is received, dumped into a memory buffer, and then displayed an entire frame at a time on the screen. The "strobed" back light is more analogous to the shutter system another poster mentioned a few posts above.
post #23 of 40
Quote:
Originally Posted by Phase700B View Post

I;m not sure your description and analogy comparing strobed back lighting to the scanned line technology of CRTs is accurate. The only "impulses" used in a CRT are those used to hit a particular pixel or spot on the phosphor screen to excite an illuminate it. All CRTs operate in a scanned fashion whereby individual lines of an image are scanned either in an interlaced odd/even fashion or sequentially in a complete progressive scanned frame. This is much different than how a flat panel LCD or plasma works where a whole frame of picture and pixel information is received, dumped into a memory buffer, and then displayed an entire frame at a time on the screen. The "strobed" back light is more analogous to the shutter system another poster mentioned a few posts above.
The truth is we're both right.

We're describing scanning backlights from different perspectives, describing separate advantages. From your perspective, you are correct when you're displaying film-based material with a scanning backlight. If you like the "projector look", then you will like a scanning backlight with 24fps movies. No disagreement, that's an advantage for such people who like the projector look. (Note: CRT projectors, driven at 48hz or 72Hz, also help provide a 'projector look' to projected films, too (48Hz is more accurate to a real projector, but flickers more). I used to own an NEC XG135 CRT projector, and often drove it at 72 Hz with 3:3 pulldown, and also used a PowerStrip tweak to do 48 Hz, too.)

However, I'm also right, for full-framerate material. To me, and other people (in the know), the big benefit of a scanning backlight is LCD motion blur reduction on interactive sources (games and computer) because it's the only possible practical method of motion blur reduction/elimination that (if properly designed) can avoid adding noticeable input lag to video games and computer use. Interpolation is more problematic for games and computers, due to input lag and artifacts.

Also, to understand how scanning backlights can reduce motion blur, it's useful to study these scientific references to understand the 'other' benefit of scanning backlights better (motion blur reduction):
Quote:
"Dynamic-Scanning Backlighting Makes LCD TV Come Alive."
by Seyno Sluyterman (InformationDisplay.org, October 2005)

"LCD motion-blur analysis, perception, and reduction using synchronized backlight flashing"
by Xiao-fen Feng (Sharp Labs. of America Inc., February 2006)

"Frame Rate conversion in the HD Era"
by Oliver Erdler (Stuttgart Technology Center, EuTEC, Sony Germany, 2008)
Page 4 has very useful motion blur diagrams, comparing sample-and-hold versus impulse-driven displays.

"Perceptually-motivated Real-time Temporal Upsampling of 3D Content for High-refresh-rate Displays"
by Piotr Didyk, Elmar Eisemann, Tobias Ritschel, Karol Myszkowski, Hans-Peter Seidel (EUROGRAPHICS 2010 by guest editors T. Akenine-Möller and M. Zwicker)
Section "3. Perception of Displays" (and Figure 1) explains how LCD pixel response blur canbe separate from hold-type (eye-tracking) motion blur.

"Flicker Fusion"
by Stephen Macknik, Barrow Neurological Institute (Scholarpedia)
Background information that relates to how flicker becomes a continuous image (applies to CRT and to scanning backlights).

"Temporal Resolution"
by Michael Kalloniatis and Charles Luu, Webvision (University of Utah)
Background information that relates to human vision behavior and how multiple flicker events, over a short interval, blends together.

"Motion portrayal, eye tracking, and emerging display technology"
by Charles Poynton (1996) Although this paper is fairly old, it accurately explains eye tracking effects and how it relates to motion blur.
Another way to explain what is Samsung CMR 960 or Sony Motionflow XR 960:

New FAQ entry about Samsung CMR 960 now added to Scanning Backlight FAQ:

Q: What is Samsung CMR 960 or Sony Motionflow XR 960?

The numbers represents a standard motion clarity equivalence to a "X fps @ X Hz" display. These proprietary names/trademarks, attached to these standard numbers, are used by some existing HDTV's with scanning backlights, and are sometimes viewed as marketing exaggerations by some reviewers. Measurements often show that they do not reflect real-world benchmarks (e.g. contrast ratio claims versus actual measurement).

However, there's a honest actual scientific basis behind these numbers (see Science & References). These motion equivalence factors are more honest in describing motion blur reduction (under certain conditions) than using "Hz" terminology. Science has shown that motion blur reduction is directly proportional to the length of impulses. Many scientific tests have shown that halving the length of strobe impulses per refresh, halve eye-tracking-based motion blur. Therefore, the shorter the strobe per refresh, and the longer the black period between refresh, the more motion blur reduction occurs. Motion equivalence factors are, in theory, directly comparable to each other on different displays, provided certain assumptions are followed.

[Edit note: This is to equalize the purpose of CRT strobes and LCD strobes (For the proper kind of motion-blur-elimination scanning backlight). This is another interpretation of the exact same formula, that is actually much simpler, provided certain assumptions are followed. See below for a list]

The formula is very simple:

. . . motion equivalence factor = 1 / length of strobe

The honesty of the formula, relative to actual measured science, assumes the following:
  • One impulse per display point (pixel) per refresh, similar to CRT.
    Actual number of backlight strobe impulses can sometimes be more than one per refresh on certain types of scanning backlights (misrepresented factor). Backlight diffusion between adjacent scanning backlight rows, can also lead to multiple impulses for a given pixel reaching the human retinas (unintentional factor). Such factors reduces measurable motion resolution, because multiple impulses are equivalent to repeated frames.
  • Full frame-rate material (e.g. 60fps @ 60Hz, or 240fps @ 240Hz)
    No repeated frames in the material, because repeated frames leads to increased perceived motion blur caused by eye-tracking. Thus, scanning backlights reduces motion blur during 60fps video games and sports broadcasts (e.g. hockey, football, NASCAR, red bull air races) far more than film-based material (e.g. 24fps non-interpolated). For video games, the graphics must be fast enough to do full frame rate (e.g. 60fps not 30fps).
  • Source material is not the limiting factor in motion blur
    Video taken with a slow shutter speed, often have built-in motion blur. Overcompressed video also have built-in blur, too. To ensure these are not limiting factors, the camera shutter speed must be faster at the source, than the length of the impulse at the destination display, and the video should not contain visible compression-related motion blur. For video games, artifical GPU motion blur effects should be disabled.

How this applies to Samsung/Sony "960" displays: Many displays using a "960" equivalence uses 240Hz refresh, combined with a scanning backlight that's dark 75% of the time. The LED impulse length is 1/960 of a second, with a period of darkness of 3/960 second between impulses (strobe duty cycle of 1/240 second). This results in 1/(1/960) which produces a motion equivalence factor of 960. The purpose of also doing a high interpolated framerate (240fps) is triple fold: It allows more impulses per second without needing a brighter backlight; it reduces scanning backlight flicker (240 Hz flicker instead of 60 Hz flicker); and it reduces stroboscopic effects. Also, other factors above, affect actual perceived motion blur reduction, such as backlight diffusion between adjacent scanning backlight sections.

How this applies to CRT: It is already well known that 60fps @ 60Hz on a CRT, have much clearer-looking motion than even 240fps @ 240Hz on a LCD. This formula explains why CRT has far less motion blur than LCD -- a CRT display has approximately a 1 millisecond phosphor decay. Such a display has motion fluidity that looks the same, to human eyes, as "CMR 1000" or "Motionflow XR 1000", or a 1000fps@1000Hz display!  No wonder CRT motion is so sharp, even  at only 60Hz!
_________________

Some additional notes:
  • Long-persistence CRT's obviously have more motion blur than short-persistence CRT's. This is compliant with the formula above.
  • Have you operated an old film pre-war-era projector that used one shorter light impulse per frame? (Those had to use shorter light impulses, due to slower film frame movement). Those have less motion blur (on sufficiently fast-enough-shutter-recorded film), provided the projector isn't vibrating/shaking the film much! This also happens to be compliant with the formula above, too!
  • Have you seen an image transmitted through a Nipkow disc? Ala 1920's television experiments? (Modern hobbyist nipkow discs use LED's instead of neon lamps, google "LED nipkow"). They are really low spatial resolution, and very dim, but have excellent temporal resolution -- better than CRT due to zero decay after pixel (spatial) illumination. No motion blur in moving objects; and scrolling text on nipkow discs are not perceptibly blurrier than stationary text. These are compliant with the formula above too!
  • Scrolling LED marquees that use line-driven LED pixels (non-capacitored) have excellent temporal resolution. Strobe lengths are so short on some models (and espeically older red-color marquees), when you track your eyes on these signs, the LED's look like they are moving along with the text. Virtually zero eye-tracking-based motion blur. These are compliant with the formula above too! Adding a capacitor to the LED's lengthens the strobes, and you see more eye-tracking based motion blur on the individual LED's in scrolling text on marquees that do not flicker (or do not use short strobe lengths). This is ALSO compliant with the formula above too!

__________________

In conclusion, the scanning backlight design needs to match the behaviour of CRT strobes (as described above), to gain the same benefits of motion blur elimination, as CRT's. Otherwise, if the assumption is violated, there is little/no motion blur elimination for a scanning backlight. So you leave behind only other advantages (e.g. "the repeated frame projector look") that scanning backlights can do. Newer scanning backlights are doing a better and better job at eliminating motion blur, thanks to technological improvements. Also, on newer LCD displays where pixel persistence/ghosting is far less than a single LCD refresh, it is now possible to use a strobed/scanning backlight to bypass the LCD pixel persistence as a limiting barrier to motion blur, simply by turning off the backlight for the entire pixel persistence period. (see diagrammatic page explaining how, here).

It is quite important to note that real-world scanning backlights do not always meet the above list of assumptions in the FAQ entry, and certain scanning backlight technologies (older scanning backlight technologies that only do imperceptible/meager (e.g. 10%) real-world motion elimination). The actual measured blur reduction is far away from the actual mathematically calculated motion blur reduction. So both you and I rightfully dismiss many of these early attempts as gimmick, but the science & theory of a scanning backlight design, for major motion blur reduction, is scientifically sound (and many clearly do see the benefit in CRT's in material meeting the critera listed above). Scanning backlights can be engineered for massive motion blur reduction/elimination. I believe we also need increased awareness about the benefits to games/computers that scanning backlights can provide (without the input lag disadvantage of motion interpolation). Recent motion resolution tests have shown that we are gradually approaching that era of less gimmickly- designed scanning backlights, that have a strobe duty cycle that much more closely resembles CRT impulses than yesterday's scanning backlight technologies. Improved motion tests need to be done. The media education about scanning backlights is extremely poor, and many early models are rightfully gimmick (see! I agree with you here), but it's certainly quite nonsense to dismiss all of them as gimmick. The ones that far more accurately emulate an impulse-driven display, are the ones with real motion blur reduction.
Edited by Mark Rejhon - 10/27/12 at 2:22am
post #24 of 40
Well, I never mentioned anything about a "gimmick", just that current/previous ]strobed back lighting is an artificial way of advertising/enhancing LCD panel refresh rate. As another poster mentioned in this thread he found it misleading for a TV maker to state a refresh rate higher than the actual native LCD panel refresh rate by including enhancement by strobed back lighting.

I think the thing that clouds things here is you keep referring to a fast on/off LED back lighting duty cycle as "scanning". And therefore try and make an analogy to CRT technology. It's not the same thing or even similar. Scanning LED back light would imply, at least to me, something different than turning LEDs on/off at a high rate of speed. The LEDs aren't being sequentially "scanned" at all in this case. So are you talking about some kind of sequential "scanning" of an LED back lighting array, or just rapid on/off duty cycle along with a higher power LED array to help with any brightness reduction? No lengthy reply needed again. Just yes or no.Because that is what get out reading your description. Nothing about "scanning" LEDs in some sort of sequence.
Edited by Phase700B - 10/27/12 at 9:29am
post #25 of 40
Quote:
Originally Posted by Phase700B View Post

Quote:
caveat emptor
+1. Information contained in a firmware or service menu may or may not take into consideration such things as "scanned" or "strobed" back light technology (the Advanced Back Lighting Technology", which is an artificial way of simulating a faster panel refresh rate. So a TV that advertises a 240HZ or 480HZ panel rate may actually be half of the advertized rate.
Tricks of the trade.
Right -- my apologies if "gimmick" was not the right word. I just interpreted you thought as such. There are, indeed, many backlight designs that goes nowhere near actually achieving its claimed motion resolution improvements, while others do a better job.
Quote:
The LEDs aren't being sequentially "scanned" at all in this case.
Some do, but not all do.
Quote:
So are you talking about some kind of sequential "scanning" of an LED back lighting array, or just rapid on/off duty cycle along with a higher power LED array to help with any brightness reduction?
Both. Yes & Yes.
They can both meet the criteria: one strobe per spatial display point per refresh.

Average power requirement is the same for a given average brightness, regardless of flash pattern. It's just power supply design. It doesn't affect that you need to squeeze high light-output into a very short time period -- regardless of strobe sequence or pattern. That is a constant for motion blur reduction, regardless of sequential scan or full-panel flash. Trying to 'cheat' (e.g. multiple impulses on the same non-interpolated frame) to get a brighter picture, violates the formula, and you only more marginally improve your motion resolution. If you want 'pure' motion blur reduction without interpolation, you need to put high peak light output into a very short time period (whether by point or pixel at a time, segment at a time, or full panel). This is a constant.

(Note: Multiple rapid strobes, on the same frame, in a single very tiny time period is okay, it just looks like one short strobe. Plasma subfield refreshes do this. For the formula, the length of strobe is the time from the beginning of the first illumination, to the end of the last illumination, for the multiple rapid strobes squeezed into a single short time period. However, you still need to squeeze a high light-output into that time period, that is still a constant.)
Quote:
No lengthy reply needed again. Just yes or no.
Yes & Yes (both)
Quote:
Because that is what get out reading your description. Nothing about "scanning" LEDs in some sort of sequence.
Any sequence, including sequential LED flashing that do actually resemble CRT. Different models and different settings generate different scanning/impulse sequences.

Scanning (sequential) and impulse (full) is the same for the human eye perspective, for motion blur reduction, for all technologies (LCD, plasma, OLED, CRT, jumbotron, etc). The motion equivalence formula is the same in all cases. The important thing, for motion blur elimination, one strobe per spatial display point per refresh, regardless of sequential scan, complete flash, forward scan, reverse scan, big segment flash, area flash, small segment flash, single pixel flash, phosphor dot illumination, sideways scan, multi scan, full, or however the strobe is done. (Note: For backlights, backlight leakage between adjacent on/off segments is a factor; it interferes with achievable motion blur elimination). Here, scientifically strictly talking about motion clarity, excluding other traits (such as more easily-seen flicker of certain flash patterns, or how closely it resembles a projector look, etc).

Note: Sequential scanning backights only *approximately* emulate CRT raster scanning. They do not do it at the single dot level, left-to-right, top-to-down. Instead, they usually scan in a row-of-LED's manner, which is a sufficiently accurate approximation (to human eyes) at the millisecond timescale. For "1000Hz" equivalence, you only need to worry about human timescales of one millisecond, and capturing 1 millisecond of a CRT scanning makes a CRT look like row-based scanning (high speed video capturing CRT scanning -- the CRT looks like it's flashing the tube in a row-based manner if we measure it on a millisecond timescale instead of on a microsecond timescale). We don't need microsecond-league timescales here (where single-pixel scanning would be become important). Not all scanning backlights designed, are sequential. Scanning backlights can have multi-scan patterns. This can reduce perceptible flicker while keeping at least (some or most) motion blur elimination benefits. (Electronics in local-dimmable displays, have complete matrix control of backlights) This is observed in high-speed video of scanning backlights. Some scan patterns are quite ineffective at motion blur elimination (e.g. multi-scan patterns have more problems with backlight diffusion). Changing scanning backlight modes can changes the scan pattern too (e.g. "Impulse" setting, etc), with more or less flicker tradeoff, versus motion blur elimination. Some even switch from scanning to full panel flash, when changing the settings. (I need to point a 1000fps camera at several scanning backlights -- something I plan to do by next year, when it's in my hands)

See my FAQ entry "Q: Is scanning the backlight better than flashing the entire backlight at once?" in my Scanning Backlight FAQ, for an explanation why scanning is often necessary due to LCD technology limitations (e.g. strobe trailing sufficiently far behind a slow scanning-based-LCD-pixel-refresh). Both scan versus strobe can achieve the same motion blur reduction, once the LCD persistence isn't the limiting factor (i.e. shutter glasses 3D panels that have fast inter-frame refresh).

Note: For my specific scanning backlight prototype (for a 23" 120Hz monitor), it is a sequential scanning backlight, because it minimizes (but not eliminates) backlight diffusion from interfering with achievable motion blur elimination, and because at native 120Hz computer output, I don't need to worry about reducing flicker via scan pattern modification. It also is configurable to full impulse mode too (this eliminates diffusion from being a factor in affecting motion resolution), and since it's just Arduino C programming, I can design any row-based scan/impulse patterns, if I want to make motion resolution comparisons. I am designing it for full normal computer monitor brightness at 1600-1920 motion equivalence factor, and half brightness at 3200-3840 motion equivalence factor. And doing it with zero "cheats"! (it requires incredible amount of lumens, however). A "pure" sequential scanning backlight (or full panel strobe) comes closest to measurably matching its "motion equivalence" factor, without the disadvantage of a full-screen strobe.

(Thank you for pointing out a deficiency in the public education of scanning backlights. I now need to construct a new FAQ entry, to explain the variety of scan patterns, including sequential and multi-scan methods of scanning backlights. Apologies if this is a lengthy response, but this topic certainly worthy of a new FAQ entry for me to add.)
Edited by Mark Rejhon - 10/27/12 at 12:40pm
post #26 of 40
I've been following your posts with fascination and interest. Lots of good information that I really wasn't aware of to the depth that you've been explaining it. However, I'm not sure what the motivation is. This is a project for LCD computer monitors and not necessarily LCD tv's, which are similar but different (if I'm mistaken I'm sure someone will correct me). What is the end-game? Certainly a fascinating project and one that I'm anxious to see the completed results of, but is this ultimately for a commercial kit that you will sell for those who want to modify their existing LCD tv's to reduce or eliminate motion blur, or just an exercise in proving a concept? Just a friendly question.
post #27 of 40
Quote:
Originally Posted by Otto Pylot View Post

I've been following your posts with fascination and interest. Lots of good information that I really wasn't aware of to the depth that you've been explaining it. However, I'm not sure what the motivation is.
I'm a CRT afficanado that loves LCD except I hate its motion blur.
Solve that without introducing dim picture or flicker, while also bypassing pixel persistence, and I'm in game heaven.
Quote:
This is a project for LCD computer monitors and not necessarily LCD tv's, which are similar but different (if I'm mistaken I'm sure someone will correct me).
My research is also applicable to watching sports that can have lots of fast pans (hockey, football, skiing, red bull air faces, NASCAR, F1, Daytona, Indy 500, etc). It merits worth paying attention to, and I want more manufacturers to adopt a scientifically proper scanning backlight design with fewer 'cheats'.
Quote:
What is the end-game? Certainly a fascinating project and one that I'm anxious to see the completed results of, but is this ultimately for a commercial kit
Ulterior motive: Presently, it's self-funded, spare-time project, out of my pocket. My ultimate goal of having my own ultimate "LCD computer monitor with the world's sharpest motion resolution", right here, on my desk. Perhaps also being able travel sometimes to show it off & convince computer monitor makers to put similar high-performance technology into their premium (Alienware-priced) computer monitors. Visit game conventions. Perhaps funded by blog donations, blog ads, kickstarter, premium/freemium software, or a sponsor. What works in my favour, is I've worked in building home theater devices -- so I know how to do this. Build the prototype and prove it can be done, but without quitting my current job. So it will probably take months of research because I want the first prototype to be essentially (for all practical purposes) guaranteed to work as advertised. Backlight diffuser experiments, high speed camera tests, motion resolution tests, etc.

Home theater addict motive: I loved working in the home theater industry when I programmed the firmware for video processors, line doublers, aspect ratio controllers, and scalers. Ten years ago. I used to calibrate CRT and DILA projectors on the side, from time to time. Eventually, all that stopped paying for food on the table, and I moved on to other industries (mobile phone software development) when video processors became commoditized and built into TV's, sales went down for dedicated processors. Work on scanning backlight is currently non-commercial. Future work or commercialization of products (even if not scanning backlight hardware which I'm making open-source, but related items such as software). The basic design of a sequential scanning backlight, is very simple and is open source, with the schematic already public. The catch is the expensive amount of backlight per square foot, for the league of 95% motion blur elimination.
Quote:
that you will sell for those who want to modify their existing LCD tv's to reduce or eliminate motion blur, or just an exercise in proving a concept? Just a friendly question.
Exercise proving the concept. A properly-engineered "pure" scanning backlight aimed directly at maximum motion blur elimination. Prejudice against scanning backlights is a significant barrier (Example: this article), brought upon by poor-performing scanning backlights that reach nowhere their actual motion equivalence factor. It's an open-source electronics circuit (Arduino), so anyone can steal the design.

See ScanningBacklight.com. I haven't released the microcontroller software, at this time -- still deciding what portion of the project should self-fund what freely released portions of project. An example of research & development I'm doing: I made a purchase order for 20,000 lumens of LED's yesterday, and got quotes from two other suppliers. About $400 worth of LED ribbons already purchased from both Chinese, Hong Kong, and USA suppliers (USA costs 4x as much, but has superior brightness) -- that's more than what most computer monitors cost. Some are on the slow boat, so waiting for them all to arrive. Comparision test between them, since I want the maximum wattage I can put into a monitor. LED's are still falling in price, so I'm paving the way a bit early for insane 150watt/sqft backlight. Initially, I need to do light output comparisions (find maximum light per square foot), and backlight diffusion testing (testing different diffusers, ranging from simple to complex stuff, mirrors, wax paper, opaque plastic sheets, expensive sheets from LCD monitor makers, etc) to find good diffusion while maximizing contrast between opposite ends of the display ("on" section versus "off section"). Equipment such as oscillscopes, Spyder/Datacolor analyzers, high-speed camera (even if just a plain Casio EX-ZR200 at low-res 480fps@240x160, or just renting a studio 1000fps camera), are planned additions to BlurBusters Lab, for testing -- for example, next year, I plan to bring a high speed camera into a large TV store & capture a catalog of discovered scanning backlight "scan patterns" and "strobe patterns" onto a YouTube channel, for comparing scanning backlight patterns and actual measured motion resolution (e.g. DisplayMate Moving Bitmaps Edition, or other test software, and software I am creating specially targetted for benchmarking scanning-backlight displays). Slowly expanding my BlurBusters Lab workshop with the necessary equipment and materials. The mere researching suppliers consumed a lot of last week's spare time. At least three people asked if they could donate equipment (though I need very specific equipment, so I had no use for some of it). I've refused small financial donations (e.g. $25 offers), though I'm open to larger donations or sponsorships so I can expand my "BlurBusters Lab". Some people want to see these sort of things happen, and see all the work be published.
Edited by Mark Rejhon - 10/27/12 at 4:11pm
post #28 of 40
Sounds like you have been a busy boy wink.gif Well keep us posted on how the research goes.
post #29 of 40
Update -- Here is some example video of a LG scanning backlight, and another video of a Samsung es8000 scanning backlight. They may be non-sequential scanning backlight for these specific models. That said, it's hard to deduce an accurate scan pattern from this because this is just high-speed shutter at real-life frame rate -- not high-speed framerate (1000fps camera) which is needed to see a more accurate scan pattern. It just goes to show that different manufacturers have come up with different scan sequences for their respective scanning backlights, and their scan sequences change when the picture settings change. (My Arduino scanning backlight is a sequential scanning backlight, but will have a full strobe mode too)
post #30 of 40
Quote:
Originally Posted by Mark Rejhon View Post

Update -- Here is some example video of a LG scanning backlight, and another video of a Samsung es8000 scanning backlight. They may be non-sequential scanning backlight for these specific models. That said, it's hard to deduce an accurate scan pattern from this because this is just high-speed shutter at real-life frame rate -- not high-speed framerate (1000fps camera) which is needed to see a more accurate scan pattern. It just goes to show that different manufacturers have come up with different scan sequences for their respective scanning backlights, and their scan sequences change when the picture settings change. (My Arduino scanning backlight is a sequential scanning backlight, but will have a full strobe mode too)

Do you know exactly how the LED Motion Plus feature works on sets like the Samsung UNxxEH6000/6030/6050/6070? I read the FAQ section of your website and was wondering where the Samsung EH 6 series stands in terms of it's LED Motion Plus feature.
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