Verification help asked for AVSHD Green and Cyan window test pattern - AVS Forum
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post #1 of 11 Old 07-08-2013, 10:26 AM - Thread Starter
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Hi everyone,

Since I have a week off, I wanted to calibrate some family members' TV's. So I went off to compare the 75% stim. 100% sat. window patterns on the AVSHD disc vs. the Iscan Duo pattern (controlled by Chromapure via the serial port).

Everything matches to within 0.001 for both x and y. Except for green and cyan y

Iscan Duo 15 % of screen area 75% stim. 100% sat. pattern

Green x = 0,301
Green y = 0,605

Cyan x = 0,227
Cyan y = 0,326

AVSHD MP4 played via WDLIVE TV about 15% of screen area (I guess) and 75% stim. 100% sat.


Green x = 0,301
Green y = 0,610

Cyan x = 0,227
Cyan y = 0,330

Can anyone verify this and conclude which of both sources is wrong? Ijust double checked and came to the same conclusion.

Cheers,
Jeroen

ps: going to either 10 or 20% of screen area does not infuence the numbers at all. Going to 100% stim. does have an effect due to the ABL. So the small diferrence in screen area (AVSHD is a bit less than 15% of screen area if I recall correctly) would not explain this discrepancy.

My gear: Panasonic TH-42PF11EK pro plasma display. -- Iscan Duo video processor -- i1 display 3 colorimeter -- i1 pro 2 spectrometer
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post #2 of 11 Old 07-08-2013, 12:30 PM
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Quote:
Originally Posted by Jeroen1000 View Post

Hi everyone,

Since I have a week off, I wanted to calibrate some family members' TV's. So I went off to compare the 75% stim. 100% sat. window patterns on the AVSHD disc vs. the Iscan Duo pattern (controlled by Chromapure via the serial port).

Everything matches to within 0.001 for both x and y. Except for green and cyan y

Iscan Duo 15 % of screen area 75% stim. 100% sat. pattern

Green x = 0,301
Green y = 0,605

Cyan x = 0,227
Cyan y = 0,326

AVSHD MP4 played via WDLIVE TV about 15% of screen area (I guess) and 75% stim. 100% sat.


Green x = 0,301
Green y = 0,610

Cyan x = 0,227
Cyan y = 0,330

Can anyone verify this and conclude which of both sources is wrong? Ijust double checked and came to the same conclusion.

Cheers,
Jeroen

ps: going to either 10 or 20% of screen area does not infuence the numbers at all. Going to 100% stim. does have an effect due to the ABL. So the small diferrence in screen area (AVSHD is a bit less than 15% of screen area if I recall correctly) would not explain this discrepancy.

Seems a bit small to even consider worrying about. .005 and .004 ...
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post #3 of 11 Old 07-08-2013, 12:58 PM - Thread Starter
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I should refresh what is considered small again by using Tom's Excel sheets. I thought 0,000x was considered small whereas +0.002 is considered significant enough to investigate.
But since I'm not sure I'm not going to argue:D

edit:s
Tom's sheet did the math for me and the "pattern error" is 0.3 dE for cyan. I guess that is not as significant as I assumed but it is something:-). This because all other colours agree perfectly within a margin of 0.001

My gear: Panasonic TH-42PF11EK pro plasma display. -- Iscan Duo video processor -- i1 display 3 colorimeter -- i1 pro 2 spectrometer
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post #4 of 11 Old 07-08-2013, 01:36 PM
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If you can't see it does it matter?
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post #5 of 11 Old 07-09-2013, 11:45 AM
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Quote:
Originally Posted by Jeroen1000 View Post

I should refresh what is considered small again by using Tom's Excel sheets. I thought 0,000x was considered small whereas +0.002 is considered significant enough to investigate.
But since I'm not sure I'm not going to argue:D

edit:s
Tom's sheet did the math for me and the "pattern error" is 0.3 dE for cyan. I guess that is not as significant as I assumed but it is something:-). This because all other colours agree perfectly within a margin of 0.001

Your Cyan between the 2 readings has about 1.1 dE2000 difference, this is something you can easily see to your screen with your eyes, if you pause your blueray with AVSHD disk Cyan Pattern and then generate the pattern from the DUO.

To calculate accurately the dE, we need the Y (Luminance) also.

Also, you have measured only one Cyan or Green Color Point from the total nearly 24.000 possible shades of Green/Cyan, this means that if you have 1.1dE only at that color points then you will propably have the same 1.1dE to some thousant color points also.....this makes the difference bigger that you thought.

Better run a 10-Point Saturation/Luminance to have a better view.

The measurements that are counts are these you are taking from your bluray as a source, since this will be your player during the bluray movie playback, for me, i don't really care what a pattern generator will tell me.... If you compare 5 difference pattern generator, you will get different reading too.

The point is to get you Actual Player closer to the Blu-Ray Movie Mastered Specs (REC.709).....don't pay attention to the pattern generator...... Using your player as a source you will fix with the correction your player inaccuracies also, because any player has different output.

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post #6 of 11 Old 07-09-2013, 12:55 PM - Thread Starter
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Hi Ted,

The dE I calculated was CIE94. I will redo it for dE2000 and I'll include Y too then and post the numbers I used. The main point I am trying to make is that x,y match to .001 for all colours except the 2 I'm talking about in this topic. This does seem to indicate (I'm choosing my words carefully here) a slight problem with the AVSHD patterns and -not- the WDLIVE media player. Otherwise, all colours should have been affected and not just green and cyan: both the Duo and the WDLIVE are accurate sources. Thus, that is my conclusion anyway.

I appreciate the fact that a given pattern generator will yield slightly different numbers. But how much difference are you seeing as I now you have a lot of toys to test with? I'm betting that, on average, it is not more than a 0.002 difference? One source of potential difference is that Duo uses %RGB. More specifically, the procentages are rounded up or down to the nearest natural number. This fact on itself WILL introduce a variation in x,y. But apparently, it is often less than 0.001. Seeing that the I1 display 3 is only accurate to at best 0.001, it cannot be stated for certain whether the I1 display 3 is "at fault" or the Duo's rounding. A lot of text to say that a repeatibility of 0.001 is beyond ok for me.

My gear: Panasonic TH-42PF11EK pro plasma display. -- Iscan Duo video processor -- i1 display 3 colorimeter -- i1 pro 2 spectrometer
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post #7 of 11 Old 07-09-2013, 02:50 PM - Thread Starter
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I'll edit my previous post to add the information I talked about, but I was already busy with the next part: grey scale.
A quick intro:

1) Room is 100% dark, even laptop screen is dimmed to its minimum and turned away from the probe. Plasma TV always gets to warm up 45 minutes up to an hour
2) I1 display pro 3 is 17 cm away from the screen. It is not at all moved during the session
3) Iscan Duo patterns are 10% of screen area. AVSHD patterns are about 15% of screen area . The small size difference only has an effect on Y and -not- on x or y.

A bit annoyingly, the differences are in the 10-30% range. Annoying because we all know probes have more difficulties getting accurate results there. Nevertheless, the results I have obtained are very repeatable.

AVSHD MP4 played via WDLIVE TV about 15% of screen area (I guess) 10% pattern

x = 0.303
y = 0.322
Y = 0.678

Iscan Duo 10% of screen area 10% pattern

x = 0.301 fluctuating to 0.302
y = 0.331
Y = 0.838

So there you have it: a significant difference in y. Strangely, the patterns agree to within 0.002 from 30% and onwards.rolleyes.gif

My gear: Panasonic TH-42PF11EK pro plasma display. -- Iscan Duo video processor -- i1 display 3 colorimeter -- i1 pro 2 spectrometer
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post #8 of 11 Old 07-09-2013, 03:02 PM
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Quote:
Originally Posted by Jeroen1000 View Post

Hi Ted,

The dE I calculated was CIE94. I will redo it for dE2000 and I'll include Y too then and post the numbers I used. The main point I am trying to make is that x,y match to .001 for all colours except the 2 I'm talking about in this topic. This does seem to indicate (I'm choosing my words carefully here) a slight problem with the AVSHD patterns and -not- the WDLIVE media player. Otherwise, all colours should have been affected and not just green and cyan: both the Duo and the WDLIVE are accurate sources. Thus, that is my conclusion anyway.

I appreciate the fact that a given pattern generator will yield slightly different numbers. But how much difference are you seeing as I now you have a lot of toys to test with? I'm betting that, on average, it is not more than a 0.002 difference? One source of potential difference is that Duo uses %RGB. More specifically, the procentages are rounded up or down to the nearest natural number. This fact on itself WILL introduce a variation in x,y. But apparently, it is often less than 0.001. Seeing that the I1 display 3 is only accurate to at best 0.001, it cannot be stated for certain whether the I1 display 3 is "at fault" or the Duo's rounding. A lot of text to say that a repeatibility of 0.001 is beyond ok for me.

No worrie about AVSHD Patterns, they have tested using a waveform monitor or by extracting the original TGA files from the M2TS Video Files.

i1D3 is can give you continious readings with only 0.0001-2 difference max for hours measuring an LCD/LED for example.

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post #9 of 11 Old 07-09-2013, 03:06 PM - Thread Starter
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@ Ted, I'm seeing a lot more than 0.001. At least 0.003 or more (see my post about the grey scale). Can't really make sense of why I'm seeing this...

My gear: Panasonic TH-42PF11EK pro plasma display. -- Iscan Duo video processor -- i1 display 3 colorimeter -- i1 pro 2 spectrometer
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post #10 of 11 Old 07-09-2013, 03:14 PM
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Quote:
Originally Posted by Jeroen1000 View Post

@ Ted, I'm seeing a lot more than 0.001. At least 0.003 or more (see my post about the grey scale). Can't really make sense of why I'm seeing this...

What display are you measuring? You have to try another intergration time value to find the one that provides you the best repeatability for your display.

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post #11 of 11 Old 07-09-2013, 03:51 PM - Thread Starter
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Your above post makes me think we are talking past each other a bit as you seem to be thinking about a repeatibility issue? For colours, only the green and cyan patterns are off between AVSHD and the Iscan Duo. And for grey scale, only 10% and 20% stimulus produce different numbers.
This is not a repeatibility issue as far as I can tell. I can repeat my numbers very very easily. When I switch between the two pattern sources, the x,y readings tumble to the same results time after time again.

My only reservation with the grey scale numbers is because I'm measuring a Panasonic PF11EK pro plasma screen. And plasma's are a bit of a challenge when we get to 10% stimulus. Note that the colours patterns have been measured at 75% stimulus so plenty of light to take a good reading.

My gear: Panasonic TH-42PF11EK pro plasma display. -- Iscan Duo video processor -- i1 display 3 colorimeter -- i1 pro 2 spectrometer
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