Anybody know why LCD's suffer from motion blur?

[DVC]

Originally Posted by 7625 QSC

LCD Motion blur is largely caused by the hold-type rendering method of LCDs together with the motion pursuing function of human visual system. This hold-type motion blur happens not on the LCD screens but in human eyes, so it cannot be captured by a still camera and therefore is physiological. Even if response time is reduced to zero, motion-blur will be observed.
So it appears, LCDs don't suffer from motion blur but the brain does.

You have provided both the correct answer and a good place to start looking for more information.

Here's my question.

In the multi-year tests of HDTVs, the ONLY LCD to provide FULL vertical resolution (almost 1080-lines) is a Samsug that uses both 120Hz and LED backlites. All other LCDs provide only about 650-lines (about 1 FIELD) of vertical resolution. Many cheap LCDs provide about half of this. Yet, most plasmas offer about 1080-lines.

So, here seems to be another difference between the technologies.

Is there some reason a 1080-line 60Hz LCD can't put 1080-lines from its deinterlacer on its screen?

When Samsung uses 120Hz technology (with interpolation) AND adds both local dimming (for darker blacks) AND LED pulsing (to introduce a dark/black pulse after each frame to reduce motion blur) then suddenly 1080-lines of video is displayed!

[rbinck]

Originally Posted by DVC

Here's my question.

In the multi-year tests of HDTVs, the ONLY LCD to provide FULL vertical resolution (almost 1080-lines) is a Samsug that uses both 120Hz and LED backlites. All other LCDs provide only about 650-lines (about 1 FIELD) of vertical resolution. Many cheap LCDs provide about half of this. Yet, most plasmas offer about 1080-lines.

So, here seems to be another difference between the technologies.

Is there some reason a 1080-line 60Hz LCD can't put 1080-lines from its deinterlacer on its screen?

When Samsung uses 120Hz technology (with interpolation) AND adds both local dimming (for darker blacks) AND LED pulsing (to introduce a dark/black pulse after each frame to reduce motion blur) then suddenly 1080-lines of video is displayed!

I have no idea where you got that information. I have a 42" Westinghouse LVM42 1080p LCD HD monitor and it displays all 1080 lines of resolution even with a 1080i input. Now when there is a 1080i input the display report shows 540 lines, but that is a bug in the Westy firmware because it displays all 1080 lines from my computer that is set for 1920x1080. The deinterlacer is completely accurate as there is no visual difference between a 1080p/60 input and a 1080i/30 input as far as spatial resolution goes.

[DVC]

Originally Posted by rbinck

I have a 42" Westinghouse LVM42 1080p LCD HD monitor and it displays all 1080 lines of resolution even with a 1080i input. The deinterlacer is completely accurate as there is no visual difference between a 1080p/60 input and a 1080i/30 input as far as spatial resolution goes.

You measured this how? Test Source? Static or motion test? Both?

[rbinck]

Originally Posted by DVC

You measured this how? Test Source? Static or motion test? Both?

Now we are talking about spatial resolution here, in other words the quantity of pixels displayed, so motion has nothing to do with it. The test source is my HTPC (computer) and I use my eyeballs. It is pretty easy to determine what the resolution is being displayed with them.

Again, where did you get your information?

[DVC]

Originally Posted by rbinck

Now we are talking about spatial resolution here, in other words the quantity of pixels displayed, so motion has nothing to do with it. The test source is my HTPC (computer) and I use my eyeballs. It is pretty easy to determine what the resolution is being displayed with them.

Again, where did you get your information?

The number of pixels sets the upper limit of resolution. The panel isn't the issue. It's the drive system and deinterlacer that determine the amount of VIDEO information that gets spread onto the panel.

So you used no test patters and your eyes. I guess that's how they sell cheap LCD.

[rbinck]

Originally Posted by DVC

The number of pixels sets the upper limit of resolution. The panel isn't the issue. It's the drive system and deinterlacer that determine the amount of VIDEO information that gets spread onto the panel.

So you used no test patters and your eyes. I guess that's how they sell cheap LCD.

I didn't say I used no test patterns, I said I used my computer. It displays the entire 1920x1080 pixels, I don't know what else to tell you.

I think you may be talking about the displays that will display the two 1080i fields as two 1920x540 frames scaled to fit the panel. That issue is not restricted to LCD panels as was shown by Gary Merson of Home Theater Magazine. I have blogged about this loss of resolution here: The 1080p HDTVs. Follow the links for Gary's testing.

As far as the 650 lines mentioned, I have no idea where that may have come from as 650 lines is not any part of any video format. Some CRT HDTVs have been tested to about those numbers of lines due to the shadow masks, but that's a whole different subject.

BTW, the swipe was noticed, but remember, it is not good to bring a knife to a gunfight.