or Connect
AVS › AVS Forum › Display Devices › Display Calibration › The Official ChromaPure thread
New Posts  All Forums:Forum Nav:

The Official ChromaPure thread - Page 112

post #3331 of 5348
Quote:
Originally Posted by KeitaroSan View Post

On white balance module, the numbers are ok on low light, but not on high light.
This is why we missed this in testing. I only looked at low light levels, because I have never seen any problem at high light levels before.
post #3332 of 5348
OK, we have fixed the Plasma mode--a simple fix with rather large consequences.

Download using the same link, uninstall the previous version, and install this one.

Everything else is the same.
post #3333 of 5348
Quote:
Originally Posted by Light Illusion View Post

The only way offset matrices can work accurately is for them to be made on the specific display to be calibrated.
This is the only way it can work accurately.
Now that I have the new release finished, I can respond to this post. Where to start. . . . ?

First, you employ a common fallacy that I have been battling ever since I got into this business. You refer to a matrix correction working "accurately". This implies a binary distinction between accurate and inaccurate. There is no such thing. There is no such thing, except as a theoretical concept, as absolute accuracy. Accuracy is always relative to some standard or level of tolerance. The SMPTE standard for accuracy is xy0.0015. I round this up to xy0.002. Any reading that is within +- xy0.002 from a reference instrument is accurate.

With that clarification out of the way, is it true that correction matrices can only be accurate when "made on the specific display to be calibrated"? No. This is simply not true. I have tested this many times. I did a test some time back with a correction matrix created on a Panasonic plasma and then used for a Pioneer plasma, but I cannot find that post, so I just did it again, this time on two different Panasonic plasma models, a ST30 and a VT30. Here's what I got. I used a JETI 1201 as a reference and an i1D3 as the colorimeter.



As you can see, the correction matrix created on a 46" inch ST30 and applied to a reading of a 55" VT30 provided an "accurate" result. The reason for this is that there are house similarities in various display technologies. This is less important with plasma than it is with LCD, which is why we have six different LCD modes in our PRO meters.
Quote:
Originally Posted by Light Illusion View Post

Doing 'generic' offsets is no better than the pre-sets included in the probe.
Well, no again. The main reason that this is incorrect is something that I discuss above. Generic factory corrections do not take into consideration meter-to-meter variation, which can be non-trivial. For example, two different i1D3s reading the exact same color on the exact same display within minutes of one another will often yield different results. These differences can be very small (LED flat panels) to something rather more substantial (LED DLP Projector), with plasma and CCFL LCD falling somewhere in between.
post #3334 of 5348
Quote:
Originally Posted by TomHuffman View Post

OK, we have fixed the Plasma mode--a simple fix with rather large consequences.
Download using the same link, uninstall the previous version, and install this one.
Everything else is the same.

Tom can you confirm the latest version is 2..3.2.39555?
post #3335 of 5348
Quote:
Originally Posted by TomHuffman View Post

You select the color format (YCbCr or RGB) and resolution in the Duo itself. The test pattern selectors (size and intensity) do carry over into auto-cal. You can use windows or fields and 75% or 100% color test patterns.

Can you use 75% Saturation Patterns in Auto Cal?
post #3336 of 5348
hello Tom,
Thanks for the version 2.3.2
Some questions on that. I noticed you removed the RGB values on the builtin patterns, but did you check the patterns themselves? Because I noticed the following:

I noticed a spike in gamma at 85IRE, but this was not there with the AVSHD pattern (see also my email to you in the past).
Builtinpattern.PNG 25k .PNG file
AVSHD.PNG 25k .PNG file

Then, I still have the same problem with CM/ACM module, as reported here in post 3258:
http://www.avsforum.com/t/1174468/the-official-chromapure-thread/3240

Problem is that 75%saturation/75%amplitude reads Y=59cd/m2 in the CM module, but 58cd/m2 in the ACM, for basically the same grey.
This corresponds with the RGB values which were printed on the pattern in version 2.3.1, which was RGB 193-193-86 in the CM module, and 190-190-85 in ACM. This corresponds with my measured Y values. Because of this, I have the impression that there is a problem with the builtin patterns.
CM.PNG 9k .PNG file
ACMbaseline.PNG 10k .PNG file
ACMsecondary.PNG 11k .PNG file
post #3337 of 5348
I see slight different contrast pattern between Auto-Cal test pattern and Mini Reference pattern when running 2.3.2

How to reproduce :
Set up contrast using the reference contrast pattern from other->reference->contrast pattern and i.e. I set it as 17 when using this pattern..
Move to Auto-call menu and press 3 buttons for test pattern before starting auto-cal and check the contrast pattern.. i.e. this time the contrast pattern Chromapure generated to Lumagen makes me to set the contrast as 22.

Tom, can you check?
post #3338 of 5348
Quote:
Originally Posted by JimP View Post

So when you profile an i1D3pro from an i1pro2, does it retain the information for the pulse/plasma feature?

Hi Jim,
Seeing as Tom said that the new Plasma Burst mode should improve the ability of the iD3, I for one will be creating a new correction profile when I next get around to using Chromapure - then I will note all the values, Ref & Field so that I can re-enter the data for the following few months.
Regards, Mike.
post #3339 of 5348
Quote:
Originally Posted by JimP View Post

So when you profile an i1D3pro from an i1pro2, does it retain the information for the pulse/plasma feature?
Profiling has no effect on the meter mode.
post #3340 of 5348
Quote:
Originally Posted by freebits View Post

I see slight different contrast pattern between Auto-Cal test pattern and Mini Reference pattern when running 2.3.2
How to reproduce :
Set up contrast using the reference contrast pattern from other->reference->contrast pattern and i.e. I set it as 17 when using this pattern..
Move to Auto-call menu and press 3 buttons for test pattern before starting auto-cal and check the contrast pattern.. i.e. this time the contrast pattern Chromapure generated to Lumagen makes me to set the contrast as 22.
Tom, can you check?
You should see a slight difference. The reference pattern locks out any adjustments that may have been made. The pattern that is used in auto-cal is adjustable, not reference.
post #3341 of 5348
Quote:
Originally Posted by Kilgore View Post

Can you use 75% Saturation Patterns in Auto Cal?
No, but you can (and should) use 75% stimulus.
post #3342 of 5348
HI Tom, Is it possible to use my D3 pro meter to measure lumens in the lumens calculator? I get stuck where I have to enter a measurement value and there is no option to "measure."

Thanks
post #3343 of 5348
Quote:
Originally Posted by atabea View Post

HI Tom, Is it possible to use my D3 pro meter to measure lumens in the lumens calculator? I get stuck where I have to enter a measurement value and there is no option to "measure."
Thanks
Use the Raw Data module to measure at 100%. Then just type that value into the Measurement Value field.
post #3344 of 5348
Quote:
Originally Posted by TomHuffman View Post

Use the Raw Data module to measure at 100%. Then just type that value into the Measurement Value field.

Thank you Tom.

atabea
post #3345 of 5348
Quote:
Originally Posted by TomHuffman View Post

This is why we missed this in testing. I only looked at low light levels, because I have never seen any problem at high light levels before.
Quote:
Originally Posted by TomHuffman View Post

OK, we have fixed the Plasma mode--a simple fix with rather large consequences.
Download using the same link, uninstall the previous version, and install this one.
Everything else is the same.

Thanks Tom, now it's working fine smile.gif
post #3346 of 5348
Quote:
Originally Posted by turboman123 View Post

hello Tom,
Thanks for the version 2.3.2
Some questions on that. I noticed you removed the RGB values on the builtin patterns, but did you check the patterns themselves? Because I noticed the following:
I noticed a spike in gamma at 85IRE, but this was not there with the AVSHD pattern (see also my email to you in the past).
Builtinpattern.PNG 25k .PNG file
AVSHD.PNG 25k .PNG file
Then, I still have the same problem with CM/ACM module, as reported here in post 3258:
http://www.avsforum.com/t/1174468/the-official-chromapure-thread/3240
Problem is that 75%saturation/75%amplitude reads Y=59cd/m2 in the CM module, but 58cd/m2 in the ACM, for basically the same grey.
This corresponds with the RGB values which were printed on the pattern in version 2.3.1, which was RGB 193-193-86 in the CM module, and 190-190-85 in ACM. This corresponds with my measured Y values. Because of this, I have the impression that there is a problem with the builtin patterns.
CM.PNG 9k .PNG file
ACMbaseline.PNG 10k .PNG file
ACMsecondary.PNG 11k .PNG file
I looked at this a bit more.

First, the greyscale at 85%IRE. On a 0-255 scale, 85% should be 216.75. In CP2.3.1, you used an builtinbit pattern 216,216,216 so rounding down. Then the level 216 on the 0-255 scale has to be converted to 16-235 for the flat panel. The level of 216 (0-255) corresponds to 185.5 on the 16-235 scale. If this is also rounded down (where is it done?), then the two rounding downs could explain why I get a peak in the gamma at 85IRE. If these assumptions to explain the problem are correct, then I think a pattern 217/217/217 would have been better.

I tested (yellow, green) again and clearly 75%saturation/75%amplitude has different Y results in the CM module and the ACM module, when using builtin patterns. This confirms that the patterns are different. That would not harm if the targets are also different in the two modules. But if that would be the case, how could the modules work properly together with external pattern generators or discs, which would use the same pattern for both CM and ACM?
Taking the case of yellow again: 100%saturation is 191/191/191 but then the 75%saturation pattern which is 193/193/86 in the CM module would give a higher amplitude.

Tom, can you give some comments on that please.
post #3347 of 5348
Quote:
Originally Posted by turboman123 View Post

I looked at this a bit more.
First, the greyscale at 85%IRE. On a 0-255 scale, 85% should be 216.75. In CP2.3.1, you used an builtinbit pattern 216,216,216 so rounding down. Then the level 216 on the 0-255 scale has to be converted to 16-235 for the flat panel. The level of 216 (0-255) corresponds to 185.5 on the 16-235 scale. If this is also rounded down (where is it done?), then the two rounding downs could explain why I get a peak in the gamma at 85IRE. If these assumptions to explain the problem are correct, then I think a pattern 217/217/217 would have been better.
I tested (yellow, green) again and clearly 75%saturation/75%amplitude has different Y results in the CM module and the ACM module, when using builtin patterns. This confirms that the patterns are different. That would not harm if the targets are also different in the two modules. But if that would be the case, how could the modules work properly together with external pattern generators or discs, which would use the same pattern for both CM and ACM?
Taking the case of yellow again: 100%saturation is 191/191/191 but then the 75%saturation pattern which is 193/193/86 in the CM module would give a higher amplitude.
Tom, can you give some comments on that please.
We made some changes in 2.3.2. Yellow in CM 75% sat, 75% amp, is not 193, 193, 86. It is 191, 191, 84. In ACM it is 190, 190, 85. This is a negligible difference, a CIE94 difference of 0.3. However, they should be consistent, so we will make this small adjustment. With green there is a 2-code value discrepancy, so we will correct this as well. So too, we will make the 1 code value adjustment to the 5% grayscale from 216 to 217.

It is good to be concerned about details like this, but if your concern is for the closest you can get to absolute precision, I would recommend not relying on the built-in test patterns at all. Their output will never be absolutely precise because of the role the video card plays. They are intended as a quick and easy way to get test patterns, and were never designed as a reference source.
Edited by TomHuffman - 11/16/12 at 3:25pm
post #3348 of 5348
Quote:
Originally Posted by TomHuffman View Post

We made some changes in 2.3.2. Yellow in CM 75% sat, 75% amp, is not 193, 193, 86. It is 191, 191, 84. In ACM it is 190, 190, 85. This is a negligible difference, a CIE94 difference of 0.3. However, they should be consistent, so we will make this small adjustment. With green there is a 2-code value discrepancy, so we will correct this as well. So too, we will make the 1 code value adjustment to the 5% grayscale from 216 to 217.
It is good to be concerned about details like this, but if your concern is for the closest you can get to absolute precision, I would recommend not relying on the built-in test patterns at all. Their output will never be absolutely precise because of the role the video card plays. They are intended as a quick and easy way to get test patterns, and were never designed as a reference source.
Thanks for the clarification Tom.

I have the following questions:
- You said you will make some adjustments. Will this be in Chromapure 2.3.2? If yes, can you inform when we can download the changes? If no, will it be in 2.3.3?
- What about 85% greyscale? Is it correct or will there be an adjustment as well?
- I am using a laptop with HDMI output. I thought HDMI being digital would be correct. Or is it still possible that the video card introduces deviations?
- If the video card is not that precise, what calibration pattern disc can we use for 75%saturation, 75%amplitude? AVSHD only has saturations at 100% amplitude. 2years ago, I downloaded patterns from your website, but now I cannot find it anymore on the website. Do you have patterns on your website for all the patterns for the CM/ACM modules? (presently, I do not want to spend money on an external signal generator).
post #3349 of 5348
Quote:
Originally Posted by JimP View Post

Are you guys referring to the built in test pattern in 2.3.2 or how 2.3.2 measures them?
If its the built in test patterns, would that also mean that the patterns in the Accupel signal generators are also off? Thought they were identical to the built in patterns.
Yes, we are and no, not at all. Apples and oranges.
post #3350 of 5348
Quote:
Originally Posted by turboman123 View Post

Thanks for the clarification Tom.
I have the following questions:
- You said you will make some adjustments. Will this be in Chromapure 2.3.2? If yes, can you inform when we can download the changes? If no, will it be in 2.3.3?
- What about 85% greyscale? Is it correct or will there be an adjustment as well?
- I am using a laptop with HDMI output. I thought HDMI being digital would be correct. Or is it still possible that the video card introduces deviations?
- If the video card is not that precise, what calibration pattern disc can we use for 75%saturation, 75%amplitude? AVSHD only has saturations at 100% amplitude. 2years ago, I downloaded patterns from your website, but now I cannot find it anymore on the website. Do you have patterns on your website for all the patterns for the CM/ACM modules? (presently, I do not want to spend money on an external signal generator).
1. We made some small adjustments in 2.3.2. We will make more in 2.3.3, which will be out shortly (just small stuff in this release).
2. Not only possible, but likely.
3. If you are asking my professional opinion, then I would recommend that you focus your attention on other issues. The discrepancies you are talking about are barely measurable and all considerably below the threshold of visibility. The ratio of concern to any practical consequence of this is out of balance. Again, just my opinion. Short of a signal generator, a calibration disc should be fine, assuming your Blu-ray player is not out of spec. Most are fine, but some require small adjustments to levels, and some of the Sony players have some small color issues. The Oppo players are virtually perfect. The GCD disc has everything you need for color calibration.
post #3351 of 5348
If I may highjack this thread a little bit, does it matter when a blu-ray player is out of spec? Since you are measuring with a meter and the software, wont the calibration make up for the "flaw" of the player?
post #3352 of 5348
Quote:
Originally Posted by JimP View Post

Quote:
Originally Posted by Wouter73 View Post

If I may highjack this thread a little bit, does it matter when a blu-ray player is out of spec? Since you are measuring with a meter and the software, wont the calibration make up for the "flaw" of the player?

Wish someone who has already figured this out could recommend alternate calibration settings to bring the most frequent out of spec broadcast within the ballpark.

i think that calibrate your BD player and/or you mediaplayer and even the game console inputs for watching films is the MAIN GOAL.

Anything else like cable/sat decoder can be setup like the calibrated BD or Mediaplayer inputs but be aware that some (most) tv channels are
bumping up colors out of the spec just to look more "vivid" or "colorful"

For sources like that just trust your eyes and accept there can be differents in grayscale and/or color.

You can experiment with the broadcasted test patterns if there are any provided by your cable/sat provider and see if that correct the visible (judged by eye) grayscale errors or use the BD/MP input settings if that doesn't satisfy you.

just my opinion..
post #3353 of 5348
Quote:
Originally Posted by JimP View Post

You'd be accurate for that player but probably not accurate for everything else.
You do bring up an interesting point. How close to spec are your source devices? So you've calibrated with an in spec player/signal generator. How close to that spec is your cable, satellite and other devices? Then you've got the variable of how the signal is transmitted. Some shows are so far out of spec that it makes me wonder if it'd be better to use one of the isf memories to tone colors down a bit.
Wish someone who has already figured this out could recommend alternate calibration settings to bring the most frequent out of spec broadcast within the ballpark.

Always a problem Jim, particularly with my Sky HD+ STB.(UK satellite).

At one stage BBC HD channel had a time during the day when they transmitted their version of a 'Test Pattern' where at least basics could be checked out.

Add to that the difference in Channels on that particular satellite regarding bit rates, band width, compression rates, SD versus HD channels and even that particular channels method of encoding its program type / content then theoretically we need to calibrate each channel available on each STB.

Most certainly there are visible differences in individual channels so my careful calibration is probably compromised by not only the decoding source but also the variability of its content.

At least a Blu Ray has a constant 'error' or can be relatively error free if a 'source direct' capability exists (eg Oppo).
post #3354 of 5348
Hello all,

about CMS calibration again, the right way to use the 75% Rec 709 setting is to use 75% saturated RGBYCM patterns with a 100% white pattern as reference? Or was the white pattern intensity not of importance?
post #3355 of 5348
Quote:
Originally Posted by Wouter73 View Post

If I may highjack this thread a little bit, does it matter when a blu-ray player is out of spec? Since you are measuring with a meter and the software, wont the calibration make up for the "flaw" of the player?
You are measuring test patterns with a meter and the software. If the output of the Blu-ray player doesn't match the test patterns, then there will be errors. BTW, we are talking about really small differences. See this Secrets article.
post #3356 of 5348
Quote:
Originally Posted by KeitaroSan View Post

Hello all,
about CMS calibration again, the right way to use the 75% Rec 709 setting is to use 75% saturated RGBYCM patterns with a 100% white pattern as reference? Or was the white pattern intensity not of importance?
You can measure 75% saturation test patterns at any level of stimulus. You just have to ensure that the white reference is at the same level of stimulus.
post #3357 of 5348
Quote:
Originally Posted by TomHuffman View Post

You can measure 75% saturation test patterns at any level of stimulus. You just have to ensure that the white reference is at the same level of stimulus.

Hi Tom,

Is there any advantage to using say 75% Luminance rather than 100% Luminance?

By that I mean is there a mathematical advantage / disadvantage regarding overall dE averages to one or the other?

Personally I have always used 75% Luminance but that is from a habit perspective (Duo patterns).

Perhaps it is like different saturation percentage patterns where your ACM will show up any variance?
post #3358 of 5348
Quote:
Originally Posted by TomHuffman View Post

1. We made some small adjustments in 2.3.2. We will make more in 2.3.3, which will be out shortly (just small stuff in this release).
2. Not only possible, but likely.
3. If you are asking my professional opinion, then I would recommend that you focus your attention on other issues. The discrepancies you are talking about are barely measurable and all considerably below the threshold of visibility. The ratio of concern to any practical consequence of this is out of balance. Again, just my opinion. Short of a signal generator, a calibration disc should be fine, assuming your Blu-ray player is not out of spec. Most are fine, but some require small adjustments to levels, and some of the Sony players have some small color issues. The Oppo players are virtually perfect. The GCD disc has everything you need for color calibration.

Thanks for the advice Tom.
So now I understand that using the builtin patterns could cause errors due to graphic card conversions.
Also, using calibration disc with a bluray player could have a problem depending on the player. And I do have a Sony, but no way to know what error that could cause.
I exclude for myself an external pattern generator, due to cost.
So what other possibilities are left?

What about patterns on an USB stick that is used directly on a flat panel. I checked the GCD thread that you referred to, and I saw that they have a mp4 file that I could use directly on my flat panel with a USB stick. Do you see any problems with that?
post #3359 of 5348
Quote:
Originally Posted by turboman123 View Post

Thanks for the advice Tom.
So now I understand that using the builtin patterns could cause errors due to graphic card conversions.
Also, using calibration disc with a bluray player could have a problem depending on the player. And I do have a Sony, but no way to know what error that could cause.
I exclude for myself an external pattern generator, due to cost.
So what other possibilities are left?
What about patterns on an USB stick that is used directly on a flat panel. I checked the GCD thread that you referred to, and I saw that they have a mp4 file that I could use directly on my flat panel with a USB stick. Do you see any problems with that?

The current Panasonic Blu-Ray players (220) i.e are known to have 0 dE error. The 220 can easily be found arount the $100 price point.
post #3360 of 5348
Quote:
Originally Posted by gtgray View Post

The current Panasonic Blu-Ray players (220) i.e are known to have 0 dE error. The 220 can easily be found arount the $100 price point.

Would you happen to know if the Panny 210 has the same 0 dE error?.

thanks

atabea
New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: Display Calibration
AVS › AVS Forum › Display Devices › Display Calibration › The Official ChromaPure thread