Reading and interpreting calibration charts and data for dummies - Page 6 - AVS Forum
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post #151 of 181 Old 12-27-2006, 07:21 PM
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I have seen some gain/bias controls that instead of functioning like you would think as a gain multiplier with an additive offset - instead the gain controls the slope of the RGB histogram above 50% the offset controls the slope of the RGB histogram below 50%. So you have to range your controls and observe how they interact - and guess at what the designers intents are with the controls. There is no standard implementation for grayscale controls.
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post #152 of 181 Old 12-30-2006, 09:25 PM
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Sorry about the noob question .

what does it mean for an HD set to have high frequency rolloff? Is this something that can be seen with test patterns?
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post #153 of 181 Old 12-31-2006, 12:03 PM
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This thread is for calibration result charts you see in calibration software and reviews - not for test patterns.

I presume a HD version of DVE or AVIA will have something similar to the existing resolution and sharpness patterns. Ask in the main forum maybe someone knows the latest.
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post #154 of 181 Old 12-31-2006, 12:49 PM
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Sorry, didn't know where to ask.
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post #155 of 181 Old 01-18-2007, 02:48 AM
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i own a 4x3 thoshiba theaterview that can convert into a 16x9 screen. if i watch a 1.85 1 movie on the 4:3 screen i get the picture with the black bars at the top and bottom if i put my tv on the 16x9 mode i can get the same exact picture but the black spaces are are much darker therefore making my picture much more outstanding. if the both show the exact same thing only the 16x9 makes the picture more outstanding, is the 16x9 mode really just masking, is it no different than the masking you have for projection screens?
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post #156 of 181 Old 01-18-2007, 11:09 AM
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This is "reading and interpreting calibration charts and data for dummies". Unless you have charts and data from calibration software that you need to know how to read and interpret - nobody is going to help you here. Try the main calibration forum or TV forums.
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post #157 of 181 Old 01-18-2007, 09:43 PM
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Good stuff
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post #158 of 181 Old 03-01-2007, 06:09 PM
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Perhaps the experts that populate this forum can help another 'dummy'
I have calibrated a Vizio GV47L 1080p TV using HCFR, DPT-94 colorimeter and a Panny S97 running the getgray disc.
S97 HDMI to TV HDMI up converted to 1080i

Posted my results here:
http://www.avsforum.com/avs-vb/showt...&page=10&pp=30
but not getting much feedback. The thread is not very active.

Is there another thread where LCD TV calibration is the main subject ?
While I have learned much here, this thread does not appear to be all that appropriate for the questions I have.

But just in case I have attached the HCFR .hcf file.

BTW the Vizio has RGB sliders in the custom color menu which were adjusted to get the best D65 gray scale. Other than that just the usual contrast, brightness, color, tint.
Used the last 2 for color decoder adjustment to get the CIE chart looking the best I could. No service menu access published, but would not use that in absence of a service manual.

 

V47-final-2-20-07.zip 3.3828125k . file

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post #159 of 181 Old 03-01-2007, 08:12 PM
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catmother -- Have you tried the "Official Vizio GV47L 1080p" thread: http://www.avsforum.com/avs-vb/showthread.php?t=777914?

Just a suggestion.

- Claus {non-Santa model}
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post #160 of 181 Old 03-01-2007, 08:43 PM
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Absolutely,
Have been posting there for some time.
Not much help there on calibration issues.
Mostly complaints about set problems issues.

My Vizio has none of those and works very well,

BTW after my HCFR calibration the PQ is excellent

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post #161 of 181 Old 03-01-2007, 09:11 PM
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Hello Catmother,

I took a quick look at your results. Overall not too shabby. It may be close to the best you can do given the controls you have available to you. To slice it much finer and get that last 5% or so, one often needs to get more precise control via LUT manipulation and ICC/ICM profiles but that doesn't seem an option for you.

The biggest thing I see is that your blue starts to get excessive (relative to R/G) at 20IRE and lower and causes your color temp to start to rise there. This perhaps could be some meter error as most all of them start to go color blind or bonkers when the light levels get low. Sometimes you have to balance what your meter tells you with what your eyeballs tell you. If you put up a grayscale ramp, do you lower IREs appear to be taking on a bluish cast relative to the whites? If not you may not sweat it too much or verify with different instrumentation.

After that, I'd suggest trying to get out of black a little quicker and get a closer fit to the 2.2 curve where you are low from 20IRE on down but that can be subjective. Again, not too shabby overall though.

Dave
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post #162 of 181 Old 04-10-2007, 05:09 PM
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For those trying to better understand CIELUV and CIELCH (color lightness, chroma strength and color hue) perceptual colorspaces may I present this simple spreadsheet for educational non-commercial purposes only - feel free to use it as long as you can keep the reference links in place.

http://krasmuzik.biz/reviews/CIE%20calcs.xls

Again a reminder that this is not a "how do I calibrate my display or use my software" thread....use the calibration forum for such posts.
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post #163 of 181 Old 04-22-2007, 07:53 AM
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Kras,
Thank you for the info.
I notice that in the 1st colum, under REC 709, the values for Y are expressed normalized to white in decimals whereas the values of Y under pre and post are expressed in absolute value. Right?
If we look at R under pre and post and compare the values, there is almost no difference on x,y but a big difference on the values of Y and dE. Since the x to y distance is very small I assume that the difference in dE is mostly due to adjustment of the Y value; yes?
I have also noticed that the value of Y for RGB do not add up to the Y value of white; when adjusting for Y, what would you rather aim to: minimize dE or try to get the Ys add up right??
Thanks for your comments.
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post #164 of 181 Old 04-22-2007, 11:21 AM
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The data is later normalized in the Xn, Yn, Zn columns - but you always want to keep unnormalized date for doing lumens and ftL calculations later. Did not matter what normalization REC709 was listed as - since I also renormalized it. Note that in Luv space normalization is to the Y component of white - which is different than Lab space that normalizes each component.

dE is the 3d magnitude of the vector formed with the LCH dimensions. So in the pre R is primarily Chroma error, but in the post LCH all contribute to the overall error but mostly Chroma is weakened because L was weaker - the actual xy did not change much. Chroma is not saturation it is color strength - we don't see saturation - we instead see color strength which is saturation and lightness mixed. L*u*v* is a perceptual space - so small errors in xy in Red are more important than larger xy errors in Green, yet this is somewhat counterbalanced - because in video Green is >3x brighter than Red - this is why a CIE xy chart is not the proper one to be used in reviews that discuss what you see.

Since it is equally weighted perceptual components - you should minimize dE - but you need dL, dC, dH details because adjusting for those errors require different controls and they likely interact. For example - it may be that reducing dL to weaken a strong dC may be the best overall dE. Or in this case Green/Cyan are the worst colors - maybe improving them at the expense of the other colors is the best overall dE. I personally prefer RMS of all dE rather than average or worst error- this is not in the spreadsheet since grading is subjective - but I discuss that in my review format on my website.

Ignore inconsistent data - this was a sensor used improperly and not tracking properly. I did not take it - but later runs the person read the lens and not the screen and got consistent data.
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post #165 of 181 Old 05-01-2007, 07:16 PM
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Thanks for this
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post #166 of 181 Old 09-06-2007, 08:37 AM
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if anyone knows why there is green in this test please post.
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post #167 of 181 Old 09-15-2007, 11:24 AM
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This is not a help me calibrate my TV or is my sensor accurate or do I know what I am doing thread...

It is a reference thread so that people can understand calibration charts - so they can go learn how to calibrate.

Please delete your post and repost it either in the main calibration forum or in your TV's forum.
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post #168 of 181 Old 10-01-2007, 08:48 AM
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Quote:
Originally Posted by krasmuzik View Post

For those trying to better understand CIELUV and CIELCH (color lightness, chroma strength and color hue) perceptual colorspaces may I present this simple spreadsheet for educational non-commercial purposes only - feel free to use it as long as you can keep the reference links in place.

http://krasmuzik.biz/reviews/CIE%20calcs.xls

Again a reminder that this is not a "how do I calibrate my display or use my software" thread....use the calibration forum for such posts.

Hello KRAZ,

Great spreadsheet! I have been reading your review format on your website and I am trying to figure out where my PJ ranks. My main source is SD (progressive) dvd (until they get this stupid format war finished). If I replace the Rec709 values with the SMPTE-C values, will the accuracy of the calculations still be valid?

-Greg
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post #169 of 181 Old 10-20-2007, 01:26 PM
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The spreadsheet is agnostic on the target - type in whatever numbers you want. I did fix where I had hardcoded the white value. dE is purely an error measure between a source and target. If you wanted to compare your sources Red against a target White - you could - actually it is interesting to do that and see the dE distance between the colors themselves vs. whites - it helps you better understand the dE magnitude.

Of course my review rankings are my subjective interpretation of dE - with me trying to be generous in public - I would be more harsh in private when deserved Which is likely why I have not publicly posted a lot of reviews
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post #170 of 181 Old 01-15-2008, 07:16 AM
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Our 46" Sony Bravia XBR4 will be delivered tomorrow. The room it will be in is only moderate light during the day and we keep the lights dimmed at night. I'm afraid the factory settings, which are set to show off its picture quality in bright showrooms, will be too "bright" for our room. I'm looking for information on the settings which I can use to "tone down" the picture to make it less "bright". I am not a techie and have no idea how to do this. Can anyone please assist me? Thank-you.
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post #171 of 181 Old 01-15-2008, 10:42 AM
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moca4

How about you read the thread especially the last few pages - which clearly state this is not a help me do my TV settings thread.
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post #172 of 181 Old 02-17-2008, 09:35 PM
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READING & INTERPRETING CALIBRATION CHARTS & DATA!!!!!!

Just scroll down the display calibration topic list until you see the "NORMAL THREADS" section. Ask as many questions regarding how to setup your new tv's there - PLEASE!!!

These threads are getting flooded with too many off-topic discussions!!!!

Carmine.
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post #173 of 181 Old 02-29-2008, 02:29 PM
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Perhaps one of you kind folks can explain what I am seeing on these charts in a manner commensurate with my level of understanding.

I have an InFocus 7210 that I have "calibrated" (term used very loosely) in the past with Avia and adjustments suggested by Bob Williams a couple of years back.

As I recently obtained a new "toy" I decided to check my Avia adjustments with the CA-6X and PL's software. I have attached the CIE graphs that I did both before and after showing both the 1931 graphs and the 1976 graphs.

Two things bother me here:

1. My grayscale adjustments did actually bring down the IRE that previously was close to 6800 down to ~6650, but it appears to me that the colors on the 1931 chart after calibration are farther from their targets than they were before I worked on the gray scale...... wah!

2. When I look at the pre and post CIE charts in the 1976 chart the pre looks okay, but the post is WAY out of the park... what the heck is going on here??? They are the same reading that produce the post_1931 chart so why would they be so very screwed up on the 1976 chart?

I will also post the IRE readings in case you guys need those to give me some ideas of what is happening. Obviously I still have work to do as so far I have only been playing with the gray scale adjustments with the RGB gains and offsets. I have not yet opened up the ISF menu (need to call InFocus and get the code) so I am not familiar with the adjustments available there.

Thank you for your assistance,
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post #174 of 181 Old 02-29-2008, 02:31 PM
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Only allow 5 files to be uploaded so here is the pre_adjustment IRE chart.

You will notice that for the foreseeable future I will use the term "adjustment" instead of calibration... :-)
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post #175 of 181 Old 02-29-2008, 02:56 PM
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Whatever I am doing wrong... is at least consistent

I went back and took a look at the charts from my "adjustments" to my Mitsubishi HD1000U.
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post #176 of 181 Old 02-29-2008, 06:25 PM
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For it to be that outta wack it has to be a software specific bug or usage error - the CIE76 gives more room to see red/blue error - but not that much!
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post #177 of 181 Old 02-29-2008, 08:17 PM
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Kevin....

that is what has my mystified... look at the 1931 graph... it is created from exactly the same data that the 1976 graph is... there is no way they should be this far apart.... (I think)..

Perhaps I should send them to Cliff and see if he can tell me what is going on........

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post #178 of 181 Old 03-04-2008, 01:10 PM
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Quote:
Originally Posted by krasmuzik View Post

For it to be that outta wack it has to be a software specific bug or usage error - the CIE76 gives more room to see red/blue error - but not that much!

Kevin........

This is the response I got from Cliff.
.................
You will see after installing the new software and using the measured primaries function in the CIE graph that your secondaries are significantly out of adjustment as you used the reference colorspace coordinates to adjust the chroma decoder, which is incorrect to use. The Primaries being so far out of alignment for Green and Red move the secondaries to entirely different points when making the calibration. By using the “Measured” primaries function we calculate the correct locations for the secondaries for you to calibrate to. You will not need the Blue filter to perform this calibration! Simply place either a Magenta/Cyan pattern on the display to measure with the probe and make the corrections with the chroma decoder using the R-Y and B-Y controls.
........................

Could you possibly translate this into English for me...? Especiially as it relates to the 7210 that I know you know very well.

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post #179 of 181 Old 06-26-2009, 09:43 AM
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Are the ISF and THX standards a secret, I can't find them doing searches, and it seems to me they would be necessary for interpreting calibration reports. You know, like gamma range, Peak White range, Delta E under x from a to b IRE, 6500K +- xK from a to b IRE?

I've been told the following:

+- 300K from 30 to 70 IRE (ISF) or +- 200K from 20 to 80 IRE (THX) from 6500K standard. Delta E under 10 from 20 to 80 IRE is both ISF and THX compliant. THX spec is 2.0 to 2.4 Gamma AVERAGE...30-37.5 ftL Peak White...Delta E under 10 from 20 to 80 IRE...6500K +- 200K from 20 to 80 IRE.
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post #180 of 181 Old 07-10-2009, 01:09 PM
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