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The Official ChromaPure thread - Page 172

post #5131 of 5345
Quote:
Originally Posted by TomHuffman View Post

Quote:
Originally Posted by millerwill View Post

Tom, So are you really saying that for a Sony1000 (soon to be 1100 with the upgrade) the 125pt CMS autocal with a LumagenMini doesn't give any better a result than simply omitting the Radiance and using the Reference preset? Is there ANY feature for which the Radiance improves things, e.g. with the BT 1886 gamma, etc.?
No. In my experience the Sony simply does not require color calibration. Of course, it does need grayscale/gamma calibration, and that's where the Lumagen can be very useful. Mark Haflich also swears by the Lumagen's scaling of 720p sources to 1080P, which he says is superior to the Sony's internal scaling.

I have the 1100's baby brother 600ES but it won't be mounted for 2-3 months. All reports so far say it has the same accuracy attributes although I'll be doing plenty of LUT exploration as well as PJ internal calibrations. What I'm really looking forward to are the next generation Lumagens, 4K, HDMI 2.0, HDCP 2.2, Darbee, and perhaps larger LUTs.

Quote:
Originally Posted by TomHuffman View Post

Quote:
Originally Posted by p5browne View Post

Would the Eecolor Box improve upon the Radiance Results?
I actually don't think that this is the right question. More to the point, the question is "Is there enough residual error to make meaningful improvement even possible?"

You can no doubt get smaller color errors with larger numbers of points. I did a preliminary test of 729 points using the Lumagen and I did get even better results, but the differences were very, very small and it takes six times longer to run a 729-point LUT than it takes to run a 125-point LUT. Is the ever increasingly small amount of error reduction worth the exponential increase in time required to achieve it? For me, no, though others may feel differently about this.

Agreed. I got into 3D LUTs in the first place because I had displays that derived a lot of benefit - Mits LaserVues and a Samsung HL67A750. Now I have a VT50 calibrated at 75% saturation and a VT60 calibrated at 100%. With LUTs I can see a subtle difference in paused video. With video content, however, switching LUTs off and on results in clearly seen color luminance differences but they mean nothing to guests when asked. Great flesh and other memory colors are there in both cases and that is all that is required unless the display is used in professional applications.

I'm actually hoping that the upcoming Vizio P and R series full array locally back lit displays have poor color tracking so a high value can be attributed to LUT calibrations. wink.gif
post #5132 of 5345
Quote:
Originally Posted by zoyd View Post

That as well as placement of test points will affect the final results. Graeme has an article about the subject available here.
Is this the same sequence of optimized patches you posted the LUT comparison thread? This site does not have a pdf of Graeme's article available.
post #5133 of 5345
Hello Tom, at ColorChecker Page of ChromaPure, I see the Gamma Target 2.25 pre-selected, do you thing is better idea to set 2.22 there as pre-selected to like the Gamma Page which has 2.22 as a default for example?
post #5134 of 5345
Quote:
Originally Posted by TomHuffman View Post

Is this the same sequence of optimized patches you posted the LUT comparison thread? This site does not have a pdf of Graeme's article available.

The patch set I uploaded is based on the approach from that article yes. You have to follow the link to conference proceedings to get it and unfortunately it's not free.
post #5135 of 5345
Anyone know why Norton would remove Chromapure.msi as soon as it is extracted?
post #5136 of 5345
Quote:
Originally Posted by kendunc001 View Post

Anyone know why Norton would remove Chromapure.msi as soon as it is extracted?



Hello, It's the Symantec's Online Network for Advanced Response (SONAR), it's checking that only a few users have used that new file and automatically deletes it. Set to 'Ask me' to have manual control. wink.gif
Edited by ConnecTEDDD - 2/25/14 at 1:27pm
post #5137 of 5345
Thanks for that. my computer skills are a little lacking.
post #5138 of 5345
Give ChromaPure a break - get rid of Norton, and go with Microsoft Security Essentials. Save Money, and speed up your ChromaPure performance at the same time!
post #5139 of 5345
Quote:
Originally Posted by p5browne View Post

Give ChromaPure a break - get rid of Norton, and go with Microsoft Security Essentials. Save Money, and speed up your ChromaPure performance at the same time!

+ infinity

Norton is excessively bloated and a resource hog....has been for 20 years now.
post #5140 of 5345
Or Avast/bitdefender...
post #5141 of 5345
Comparison of 125-point LUT 1 pass and 2 pass

In 2.5 we greatly enhanced the operation of advanced auto-cal LUT, now calculating the corrections rather than using reiterative measurement. We offered the ability to take 1, 2, or 3 passes. First, 3 passes is completely useless. This will be removed in the next release. However, since 2 passes takes double the time from a single pass, I wanted to quantify the difference.

First, let's look at the red and green primaries.



As you can see, almost all of the error was removed in the first pass. The difference between the first and second pass is about 0.5 dE.

Next, let's look at a saturation sweep.

1 Pass

AdvancedColorManagementReport125-1Pass.pdf 1596k .pdf file

2 Passes

AdvancedColorManagementReport125-2Pass.pdf 1600k .pdf file

The difference here is even smaller, essentially indistinguishable (0.8/0.9 dE)

Finally, a ColorChecker run (Before is 1 pass, After is 2 passes)

checkerReport.pdf 352k .pdf file

The standard ColorChecker shows only a 0.3 difference (1.0/0.7), but the skin tones show a somewhat larger difference of 0.6 (1.4/0.8).

First, the data seems to show that although 2-passes does improve the results, it improves them by such a small amount that it is doubtful whether it is worth the extra time. However, two passes of the 125-point LUT only takes about 15 minutes, so there is very little extra effort involved. Second, the vanishingly small color error measured after a two-pass 125-point correction throws even more doubt on the potential benefit of a 729 color and even larger LUTs. Of course, I cannot be certain about this without measuring a much larger collection of color samples. I will do this in the near future.
Edited by TomHuffman - 2/27/14 at 9:15pm
post #5142 of 5345
Is this a 125 Point only sweep, X2, X3 or, 21 Grayscale, 125LUT, 21 Grayscale, 125LUT, 21 Grayscale, 125LUT , where they interact with each other. I personally do 3 sweeps finding, even then, they're still leaving some error in each, due to the interaction.
post #5143 of 5345
Quote:
Originally Posted by p5browne View Post

Is this a 125 Point only sweep, X2, X3 or, 21 Grayscale, 125LUT, 21 Grayscale, 125LUT, 21 Grayscale, 125LUT , where they interact with each other. I personally do 3 sweeps finding, even then, they're still leaving some error in each, due to the interaction.
It is a 125 plus 11-point grayscale sweep. Here's the post-calibration values

10% 0.312 0.333
20% 0.310 0.330
30% 0.312 0.329
40% 0.312 0.329
50% 0.312 0.329
60% 0.313 0.329
70% 0.313 0.329
80% 0.313 0.329
90% 0.312 0.329
100% 0.314 0.327

There's no interaction that I see.
post #5144 of 5345
Tom

Would there be a benefit to weighting many of the color read points to be the skin tones?
post #5145 of 5345
Quote:
Originally Posted by JimP View Post

Tom

Would there be a benefit to weighting many of the color read points to be the skin tones?
No, I think you would want a wider sample of the color space.
post #5146 of 5345
Quote:
Originally Posted by buzzard767 View Post

I have the 1100's baby brother 600ES but it won't be mounted for 2-3 months. All reports so far say it has the same accuracy attributes although I'll be doing plenty of LUT exploration as well as PJ internal calibrations. What I'm really looking forward to are the next generation Lumagens, 4K, HDMI 2.0, HDCP 2.2, Darbee, and perhaps larger LUTs.
Agreed. I got into 3D LUTs in the first place because I had displays that derived a lot of benefit - Mits LaserVues and a Samsung HL67A750. Now I have a VT50 calibrated at 75% saturation and a VT60 calibrated at 100%. With LUTs I can see a subtle difference in paused video. With video content, however, switching LUTs off and on results in clearly seen color luminance differences but they mean nothing to guests when asked. Great flesh and other memory colors are there in both cases and that is all that is required unless the display is used in professional applications.

I'm actually hoping that the upcoming Vizio P and R series full array locally back lit displays have poor color tracking so a high value can be attributed to LUT calibrations. wink.gif

Have you ran a full LUT on a ST60? Apparently there is an issue with the color decoder possibly green. How would you go about diagnosing this as well as the Green Skin issue? I use Chromapure but don't know how to use the skin tone patterns , I have GCD which has the 24 color checker. Do I display the pattern using my bluray player then click on the corresponding pattern in chromapure to take the measurement?
post #5147 of 5345
Quote:
Originally Posted by hungro View Post

Have you ran a full LUT on a ST60? Apparently there is an issue with the color decoder possibly green. How would you go about diagnosing this as well as the Green Skin issue? I use Chromapure but don't know how to use the skin tone patterns , I have GCD which has the 24 color checker. Do I display the pattern using my bluray player then click on the corresponding pattern in chromapure to take the measurement?
You diagnose color decoder problems simply by looking at primary luminance and secondary hues. Are they far out of spec?

Yes, exactly.

Edit: I don't think that the ST60 has a color decoder problem.
Edited by TomHuffman - 3/2/14 at 1:40pm
post #5148 of 5345
Quote:
Originally Posted by TomHuffman View Post

You diagnose color decoder problems simply by looking at primary luminance and secondary hues. Are they far out of spec?

Yes, exactly.

Edit: I don't think that the ST60 has a color decoder problem.

Do you know then what is causing this much talked about Green Skin Tone issue? Gamma perhaps?
post #5149 of 5345
Quote:
Originally Posted by hungro View Post

Do you know then what is causing this much talked about Green Skin Tone issue? Gamma perhaps?
I haven't seen it, so I can't say. From what I have read seems to indicate that it comes and goes depending on the scene. The standard culprits would be white balance and color accuracy within the gamut.
post #5150 of 5345
Tom,

I was noticing that with the most recent version of Chromapure, that selecting windows in signal generator device settings, will select a 10% window on the Accupel 5000. It use to select the 10.8% window.

Was this intended?
post #5151 of 5345
Quote:
Originally Posted by JimP View Post

Tom,

I was noticing that with the most recent version of Chromapure, that selecting windows in signal generator device settings, will select a 10% window on the Accupel 5000. It use to select the 10.8% window. Was this intended?
Yes.
post #5152 of 5345
I just ordered Chromapure standard with an Eye One to calibrate my JVC RS57. I cant wait to try it and see what improvements it brings. I am also curious to measure how far my actual settings are from a calibrated display. I find the uncalibrated picture amazing already...
post #5153 of 5345
Quote:
Originally Posted by turboman123 View Post

Hello Tom,
In order to understand this and see the effect, I selected gamma max, neutral and minimum on my Samsung LED, and measured saturations. Results depended on the gamma selected. Of course, max and min gamma setting is out of the normal for this panel, but I just wanted to understand the effect.

If I would prefer a BT1886 gamma and do a manual calibration with a calibration disc, which would you recommend of the following 4 methods:
A: Do all the calibrations with gamma 2.22 with more than one pass, and as a last step change gamma to BT1886 without touching greyscale or CMS anymore.
B: Same as above but as a last step change gamma with greyscale adjustment but without CMS adjustment.
C: Do all the calibrations including BT1886, again more than one pass. I understand then this would lead to some error in the saturation measurements or CMS settings if I base CMS settings on saturations below 100%.
D: Or stick to gamma 2.22 for everything and leave it at that.
(If the preferred method depends on the panel, I have a Samsung F8000)
Quote:
Originally Posted by turboman123 View Post

hello Tom,
See my earlier question. Any recommendation on this?

hello Tom,
I am still looking for the best way to make a manual calibration of advanced CMS with BT1886 and calibration disk. See my earlier post. Can you give a recommendation? If my question was not understandable, I can rephrase it.

Of course I am looking for the best way to make an advanced CMS calibration with BT1886 with the present version of Chromapure. I understand that presently, manual advanced CMS calibration with a gamma different from 2.22 contains some errors. Do you see a possibility that a future version of Chromapure will take a different gamma into account when making an advanced CMS calibration?
post #5154 of 5345
Quote:
Originally Posted by turboman123 View Post

I am still looking for the best way to make a manual calibration of advanced CMS with BT1886 and calibration disk. See my earlier post. Can you give a recommendation? If my question was not understandable, I can rephrase it.

Of course I am looking for the best way to make an advanced CMS calibration with BT1886 with the present version of Chromapure. I understand that presently, manual advanced CMS calibration with a gamma different from 2.22 contains some errors. Do you see a possibility that a future version of Chromapure will take a different gamma into account when making an advanced CMS calibration?
I assume that you are referring to the Advanced Color Management module. You cannot do a manual calibration inside the gamut. For that, you need to use a Lumagen LUT and advanced auto-cal, which has BT.1886 as an option. The reason you can't do a manual calibration is that--without an LUT box--you lack the controls to adjust colors inside the gamut. BTW, Samsungs in the Movie mode should be pretty good inside the gamut without an LUT calibration. What does your calibrated Movie mode ACM report look like?

The only purpose of the ACM module is diagnostic. It is a great way to test whether your display needs an LUT calibration and to determine--along with the ColorChecker module--how successful the LUT calibration has been.

Because the color differences between the same color at different gammas in the 2.22-2.4 range are so small, it is not really necessary to have gamma selection in ACM. Again, its purpose is purely diagnostic and in this context dEs of about 1.0 (which is about the maximum I would expect to see as a color difference between BT.1886 and 2.22) just don't matter.

Am I misunderstanding you?
post #5155 of 5345
Quote:
Originally Posted by TomHuffman View Post


Because the color differences between the same color at different gammas in the 2.22-2.4 range are so small, it is not really necessary to have gamma selection in ACM. Again, its purpose is purely diagnostic and in this context dEs of about 1.0 (which is about the maximum I would expect to see as a color difference between BT.1886 and 2.22) just don't matter.

Here is some data on the error reporting differences when you use a 2.2 power law gamma to calculate dE94 errors for a display with a BT.1886 transfer function. Data taken with 1000 random perceptual volume filling colors.

Black diamonds: white=130 cd/m^2, black=0.028 cd/m^2
mean difference = 0.36 max difference = 1.1

Blue triangles: white=130 cd/m^2, black=0.046 cd/m^2
mean difference = 0.44 max difference = 1.9

Scatter plot

Edited by zoyd - 3/8/14 at 12:52pm
post #5156 of 5345
Hi, Tom, why in auto-calibration when I select GRAYSCALE / GAMMA and COLOR GAMUT and to RADIANCE GRAYSCALE / GAMMA 11 POINTS, COLOR GAMUT 8 points at the end the autocalibration calculated GRAYSCALE/GAMMA to 12 points and the advanced color gamut 125 points and not color gamut 8 points?
post #5157 of 5345
Quote:
Originally Posted by stefanelli73 View Post

Hi, Tom, why in auto-calibration when I select GRAYSCALE / GAMMA and COLOR GAMUT and to RADIANCE GRAYSCALE / GAMMA 11 POINTS, COLOR GAMUT 8 points at the end the autocalibration calculated GRAYSCALE/GAMMA to 12 points and the advanced color gamut 125 points and not color gamut 8 points?
Auto-cal always uses 12 pt. All this is is 11 pt with the 5% pt activated.

You selected 8-point and it ran 125 point?
post #5158 of 5345
Quote:
Originally Posted by TomHuffman View Post



You selected 8-point and it ran 125 point?
Yes.
post #5159 of 5345
Quote:
Originally Posted by TomHuffman View Post

I assume that you are referring to the Advanced Color Management module. You cannot do a manual calibration inside the gamut. For that, you need to use a Lumagen LUT and advanced auto-cal, which has BT.1886 as an option. The reason you can't do a manual calibration is that--without an LUT box--you lack the controls to adjust colors inside the gamut. BTW, Samsungs in the Movie mode should be pretty good inside the gamut without an LUT calibration. What does your calibrated Movie mode ACM report look like?

The only purpose of the ACM module is diagnostic. It is a great way to test whether your display needs an LUT calibration and to determine--along with the ColorChecker module--how successful the LUT calibration has been.

Because the color differences between the same color at different gammas in the 2.22-2.4 range are so small, it is not really necessary to have gamma selection in ACM. Again, its purpose is purely diagnostic and in this context dEs of about 1.0 (which is about the maximum I would expect to see as a color difference between BT.1886 and 2.22) just don't matter.

Am I misunderstanding you?

hello Tom,
Thanks for the explanation. I am surprised you say that the ACM module is purely diagnostic. My understanding is as follows, and I make an analogy with the white balance controls and greyscale. With 10p white balance controls, you can calibrate all IRE's, and with a 2p white balance control, you can calibrate the greyscale to get a best fit for the greyscale line, but not individual greyscale points.
In the same way, I had understood that with a LUT, you can control a number of points within the gamut individually. But without a LUT, you can use the CMS controls to reduce errors of the gamut points and within the gamut, not individually but overall. Lets say with a CMS setting optimized for the 100% gamut points, I can get dE 1 at the gamut points, and dE 4 at 75% saturation. Or I can change the CMS setting to get dE 2 for both 100% and 75% saturation. So I look at all saturations (and luminances) when setting the CMS controls using the ACM module. That is how I did it (right or wrong), and I have seen other forum users doing the same.
Is this a valid way of using CMS controls and ACM module? If yes, which saturation points and luminance should I give priority when setting the CMS?

If the way I do it is OK (of course it is a lot more work, but I use Chromapure for private fun only), how then to do it when using BT1886 gamma (that was the question in my previous post)? I understand you say that the errors are small, but I still would like to have more fun playing with Chromapure, without spending money on a LUT maschine.

(I am away from home now, so cant show the ACM for my Samsung 55F8000).
Edited by turboman123 - 3/9/14 at 1:32am
post #5160 of 5345
Quote:
Originally Posted by turboman123 View Post

Thanks for the explanation. I am surprised you say that the ACM module is purely diagnostic. My understanding is as follows, and I make an analogy with the white balance controls and greyscale. With 10p white balance controls, you can calibrate all IRE's, and with a 2p white balance control, you can calibrate the greyscale to get a best fit for the greyscale line, but not individual greyscale points.
In the same way, I had understood that with a LUT, you can control a number of points within the gamut individually. But without a LUT, you can use the CMS controls to reduce errors of the gamut points and within the gamut, not individually but overall. Lets say with a CMS setting optimized for the 100% gamut points, I can get dE 1 at the gamut points, and dE 4 at 75% saturation. Or I can change the CMS setting to get dE 2 for both 100% and 75% saturation. So I look at all saturations (and luminances) when setting the CMS controls using the ACM module. That is how I did it (right or wrong), and I have seen other forum users doing the same.
Is this a valid way of using CMS controls and ACM module? If yes, which saturation points and luminance should I give priority when setting the CMS?

If the way I do it is OK (of course it is a lot more work, but I use Chromapure for private fun only), how then to do it when using BT1886 gamma (that was the question in my previous post)? I understand you say that the errors are small, but I still would like to have more fun playing with Chromapure, without spending money on a LUT maschine.

(I am away from home now, so cant show the ACM for my Samsung 55F8000).
I suppose that if you wanted to spend the time on it, you could experiment with different CMS settings and then pick the one setting that offers the smallest dE across all of the points. That is a perfectly valid, though I would think agonizingly tedious, approach.

ACM was originally developed when there was no consumer LUT option. It was intended primarily as a diagnostic tool, but sometimes users find ways of using the controls in the program that I never thought of, which is fine.

In any case, since you are using a calibration disc rather than an external signal generator, it is not clear to me how you would even use BT.1886 since the targets it specifies are calculated dynamically. It is not as if a disc can have ACM test patterns for BT.1886 targets, because those targets will vary depending upon the white and black level of each display. For example, the test patterns provided for the ColorChecker and ACM modules are valid for a specific gamma. In the ColorChecker module we offer a gamma selector that has the effect of changing the targets slightly to accommodate the selected gamma, but this only works if you are using a signal generator.

There is no single point to "give priority" to. I would just select the CMS setting that provides the lowest average dE for all of the saturation points.

On our development roadmap is the ability to set gamma once and have it apply to all modules, including ACM. However, it will be a while before this is implemented.
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