Colorimeter spreadsheet for SpyderTV - Page 4 - AVS Forum
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post #91 of 207 Old 01-25-2006, 05:19 PM
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News just in.

Thanks to some help from Jeff, it looks like the spreadsheet is just fine, as it conforms to Rec 709. CF may be using a simple power function calculation which is why the answers are different. I'll be interested to hear from the CF people regarding this as well.

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post #92 of 207 Old 01-25-2006, 06:01 PM - Thread Starter
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Quote:
Originally Posted by AK47 View Post

I have similar experience ... in fact, I'm puzzled by the following equation which is widely used in the spreadsheet:-

measured value + 0.099/1.099

grateful if someone good at maths enlighten the crowd

The gamma calculation is based on the Rec 709 equation. See here:
http://people.ee.ethz.ch/~buc/brechb...Q.html#RTFToC5
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post #93 of 207 Old 01-25-2006, 07:25 PM
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Quote:
Originally Posted by rader View Post

The gamma calculation is based on the Rec 709 equation. See here:
http://people.ee.ethz.ch/~buc/brechb...Q.html#RTFToC5

Thx. Radar for the quick reply.

The reason why I raised the query is that I've done a monitor calibration with Spyder2Pro to a gamma value of 2.22 but when I tried to verify the calibration results by re-measuring (Colorimeter Tools), I got a gamma value of 3 on the GetGray sheet!! The funny part is that when I copy the 10-100 IRE results to the AVIA sheet w/o correction (and delete everything in the 0 IRE boxes), it gives me almost a gamma of 2.21! So, I'm still puzzled.

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post #94 of 207 Old 01-25-2006, 07:30 PM
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Here's my measurement file.

 

200W6-VGA.zip 55.029296875k . file
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post #95 of 207 Old 01-26-2006, 12:18 AM - Thread Starter
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AK,
I tried looking at your measurements and using the simplified CRT style gamma function it shows a gamma of about 2.4, which is still quite a ways off from what the Spyder2Pro set. I would attribute the Avia sheet reporting 2.21 as dumb luck - it can really only be used with Avia levels.
Besides that I can't give you a real answer. The Spyder2Pro did a nice job on my LCD computer monitors but it applied a funky correction curve to my CRT RPTV which resulted in lots of banding and washed out blacks. I may have done something wrong but after that I stopped using it.
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post #96 of 207 Old 01-26-2006, 12:41 AM
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Thx. Rader

I got the same value of 2.4 by changing the formulae in your spreadsheet, but I'm quite happy with the calibrated picture. It's time to re-calibrate according to Spyder2Pro's recommendations. This time I'll do the DVI as well. Hopefully, I'll get a closer match.

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post #97 of 207 Old 01-26-2006, 12:52 AM
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BTW, I checked the primary color co-ordinates of my LCD monitor with Lumagen's internal test patterns and noticed a strinking color gammat with IRE. Is that normal?
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post #98 of 207 Old 01-26-2006, 08:50 AM
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Quote:
Originally Posted by rader View Post

Thanks for the tip Bill - it would make things much easier if I figured out a way to calculate gamma without measuring black.

Shawn - Looking at the sRGB specs, and trying to back into what some of the Rec709/SMPTE-C documentation says, seems to indicate to me that a gamma function is supposed to include the non-zero black level as part of the foundation for determining the theoretical gamma values. This was what Jeff was indicating. However, if Poynton is correct, then what you really want is for 99% stim to be JND* from 100%. Using CIE Luv, one could do a rough calculation of this (L*), but given the controversy over Delta E*, I'm not sure that this would necessarily produce a better answer than the analytical shorthand that Jeff (and I) use. It would certainly be more computationally intensive.

Alternatively, one could notice that when you normalize, you are usually using a fairly high number (reference white with my H77 runs between 400 and 500 cd/m^2). At that point, the 0.2 cd/m^2 black level is really a rounding error when we talk about normalization. If you use a curve-fit method (e.g., log-linear regression, preferably with >15 measurement points), then the rounding for black level and normalization pretty much get washed out.

So, basically start from 100% and calculate JND down to 0%, or go with a regression method to avoid having to measure a 0% value (even though it doesn't get used in most people's calculations other than to tweak the normalization process).

By the way, you should link directly to Poynton's site, rather than to a mirror. He's got some great stuff there that folks who are using your stuff ought to read.

Later,
Bill

* JND = Just Noticeable Difference
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post #99 of 207 Old 01-29-2006, 03:37 PM
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I purchased the SpyderTV last week and downloaded radar's spreadsheet. I had previously calibrated my Toshiba 42HP95 42" plasma with DVE and AVIA. The Spyder settings came out almost identical to what I had, except for contrast. It indicated a value of 82 (on a scale of 100), where I always had adjusted it to 40-50 range. I left it at 50. The Spyder also indicated a cool color temperature, which was to be expected.

I used the /support mode to do a complete gray scale alignment using radar's spreadsheet. The initial run showed a color temp of around 10,000 at level 10, then flattened out to about 7500 from 40 upward. RGB levels showed blue way high, green and red were not to bad. Gamma was very ragged.

After several more runs and adjustments to gray scale in the service menu, I got gray scale to within 200k of 6500k from 20IRE upward. RGB levels are within 5% from 20 on up. The total gamma is 2.33 and very smooth. DeltaE is from 1 to 4 from 20 upward. The 10IRE level has a color temp of 7500k and DeltaE of 14.

I calibrated through the component input with a 480p output from my DVD player. My question is this. Is my calibration accurate, even though the spreadsheet is set up for Rec 709, and I was sending the TV a non-HD signal of Rec 601?

To me, 6500k should be the same no matter what the primaries are. Am I correct, and please explain if I am not.

Thanks,
Duke

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post #100 of 207 Old 01-31-2006, 02:56 PM
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Quote:
Originally Posted by mrduke View Post

I purchased the SpyderTV last week and downloaded radar's spreadsheet. I had previously calibrated my Toshiba 42HP95 42" plasma with DVE and AVIA. The Spyder settings came out almost identical to what I had, except for contrast. It indicated a value of 82 (on a scale of 100), where I always had adjusted it to 40-50 range. I left it at 50. The Spyder also indicated a cool color temperature, which was to be expected.

I used the /support mode to do a complete gray scale alignment using radar's spreadsheet. The initial run showed a color temp of around 10,000 at level 10, then flattened out to about 7500 from 40 upward. RGB levels showed blue way high, green and red were not to bad. Gamma was very ragged.

After several more runs and adjustments to gray scale in the service menu, I got gray scale to within 200k of 6500k from 20IRE upward. RGB levels are within 5% from 20 on up. The total gamma is 2.33 and very smooth. DeltaE is from 1 to 4 from 20 upward. The 10IRE level has a color temp of 7500k and DeltaE of 14.

I calibrated through the component input with a 480p output from my DVD player. My question is this. Is my calibration accurate, even though the spreadsheet is set up for Rec 709, and I was sending the TV a non-HD signal of Rec 601?

To me, 6500k should be the same no matter what the primaries are. Am I correct, and please explain if I am not.

Thanks,
Duke


Excellent information and questions Mr. Duke. I too look forward to a response.
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post #101 of 207 Old 01-31-2006, 06:21 PM
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post #102 of 207 Old 02-13-2006, 08:32 AM
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Hello,

I used Rader's Spreadsheet along with a SpyderTV colorimeter and was able to use this successfully.

I have a question though. I used my DVD player outputting at 480P to my TV and using the DVE test patterns. Should I be using the Rec 709 or Rec 601 values? Rader's spreadsheet is set up for Rec 709 and I was wondering if I need to change it to use Rec 601 values? I have been looking around but haven't found a definitive answer.

The reason I ask is that looking at HD pictures, the color looks good. When I look at SD, the colors seem to be strong. Can't tell if I have a bad adjustment or just sh**ty D* feeds. Currently my OTA is set up to only receive digital channels and I couldn't get any HD shows on that last night (too late). Also I have a Samsung DVD that will upconvert and I did a quick check with it at 1080i (using spreadsheet, colorimeter, and test patterns) but I think that the color converter on the unit is not very good.

Thanks
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post #103 of 207 Old 02-13-2006, 09:22 AM - Thread Starter
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It will not hurt anything to try switching the transform matrix to Rec 601. brucelindbloom.com has the transfrom matrices listed somewhere on his web page. I beleive you want the one listed as STMPE-C XYZ->RBG. Changing the R709 transform matrix will only change the shape of the color error graph and gamma curves.
Regardless of which color space you use the end goal is to get the (x, y) values as close to (.313, .329) as possible. The Delta-E graph is what tells you how accurate your picture is (lower is better) and it is not based on R709. The big caveat here which I have probably not pointed out as much as I should have is the Avia correction factors in the spreadsheet do not correct the Delta-E graph.
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post #104 of 207 Old 02-13-2006, 10:10 AM
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Anyone using this with the built in test patterns in a Lumagen scaler? If so which tab in the spreadsheet is most appropriate (DVE, GetGray,Avia)?

Thanks,

Shawn
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post #105 of 207 Old 02-13-2006, 10:17 AM
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I would think the one that corresponds to the test disk you are using.

Gary

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post #106 of 207 Old 02-13-2006, 12:32 PM
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" I would think the one that corresponds to the test disk you are using."

That was the point, not using a test disk. I wanted to see about using the built in internal test patterns in my Lumagen scaler for calibration......

Shawn
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post #107 of 207 Old 02-13-2006, 12:38 PM
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Ah, I see your point

Getgrey;s are more accurate than Avia, so that woule probably be the best one to use. I didn't realise he now had a DVE tab on the sheet. What are the differences between DVE and GGs?

Gary

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post #108 of 207 Old 02-13-2006, 02:26 PM
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Quote:
Originally Posted by sfogg View Post

" I would think the one that corresponds to the test disk you are using."

That was the point, not using a test disk. I wanted to see about using the built in internal test patterns in my Lumagen scaler for calibration......

Shawn

Bear in mind that in this case you would just be calibrating the output of the scaler to the display, not taking into account your source. If the source is digital, then probably no big deal. If the source is analog you might have miscalibration. Take this with a grain of salt, but it is as I currently understand it (I have an HDP too).

Seriously. AVS is a place where you go to learn to be unhappy. - Bear5k
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post #109 of 207 Old 02-13-2006, 02:44 PM
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Yup, all my important sources to the HDP are either DVI or SDI so I'm not terribly worried about the source calibration. My plan was to get the projector calibrated using both the projectors controls and the greyscale functions in the Lumagen as needed. Then double checking the simple settings on the source and adjust them either at the source itself or using the per input functions in the Lumagen.

Shawn
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post #110 of 207 Old 02-13-2006, 03:08 PM - Thread Starter
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Quote:
Originally Posted by Gary Lightfoot View Post

= What are the differences between DVE and GGs?

Gary

The DVE tab has levels at only black, 20%, 40%, 60%, 80% and 100%. The tab is for the non-pro version.
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post #111 of 207 Old 02-13-2006, 03:13 PM
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Thanks Rader.

Gary

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post #112 of 207 Old 03-05-2006, 01:58 AM
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Hi all

Do any of you have suggestions on what to read so I can use SpyderTV correctly and understand what's going on with the data as I experimented taking readings last night with xbox360 dvd player on av1 using avia and from what I understand they where way out so out the gamma curve was all over the place so its definitely something I'm doing and need to lern more.
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post #113 of 207 Old 04-10-2006, 06:25 AM
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Tks, Rader. will try your spreadsheet and hope can figure out by myself.
SpyderTV user.

BTW, still confused the temp definition by different makers.
warm = high temp
or warm = low temp?

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post #114 of 207 Old 04-10-2006, 09:07 AM
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Most manufacturers relate "warm" to a lower color temperature. With many displays even "warm" is still too high. I used the SpyderTV and radar's spreadsheet on my Toshiba 42HP95 plasma, and found the "warm" setting produced a color temp of 7500. I was able to correctly adjust it using the service menu though. Also when using the spreadsheet, the actual x, y coordinates are the most important for setting gray-scale and getting the proper colors. Get those DE values as low as possible.

I think radar's spreadsheet is a great contribution to all of us do-it-yourself calibrators. And the input from many others about the spreadsheet (especailly URSA and UMR) has been fantastic! Maybe the SpyderTV and spreadsheet aren't quite as good as a well done ISF calibration, but they appear to be close, and it sure is fun to DIY!

Duke

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post #115 of 207 Old 04-14-2006, 08:31 AM
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Nice work rader!

I've been using your sheet with my Spyder2pro to calibrate my new Dell 2405 LCD monitor... warm-up exercise before tackling my Pio 1130HD. (I went with the spyder2pro over the spyderTV because I also wanted to calibrate my printer, so I went with the Print Pro Suite).

For those of us using this on our computer monitors, any chance of adding an sRGB colorspace tab?

Cheers!
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post #116 of 207 Old 04-14-2006, 10:34 AM
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Quote:
Originally Posted by eh? View Post

Nice work rader!

I've been using your sheet with my Spyder2pro to calibrate my new Dell 2405 LCD monitor... warm-up exercise before tackling my Pio 1130HD. (I went with the spyder2pro over the spyderTV because I also wanted to calibrate my printer, so I went with the Print Pro Suite).

For those of us using this on our computer monitors, any chance of adding an sRGB colorspace tab?

Cheers!

eh?,
How exactly are you using Rader's spreadsheet to calibrate the dell 2405FPW? I have the same monitor, and all settings (except brightness) is disabled when connected through DVI? Are you just profiling the video card. You can just use the Spyder Pro wizard to do that without using the spreadsheet? Please explain...
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post #117 of 207 Old 04-14-2006, 03:23 PM
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I'm adjusting the red/green/blue sliders.

I adjust the sliders, and then take readings using the colorimeter tool setting the window at various grey levels (51, 51, 51; 76, 76,76; 102, 102, 102; etc) and input the readings for xyY and colour temp into the spreadsheet to track Gamma, Colour temp, and Delta E

The thing I have noticed is that the wizard sets you up with a colour profile which is near bang on for the gamma, but not so good on the Colour temp... mine usually comes in at around 6700 -

Setting up the monitor on my own, finding the right relative and absolute levels of RGB, using the sliders, I can get a much better overall colour temp (between 6400-6600)- but the gamma is slightly off (2.23 for red and green, 2.19 for blue)
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post #118 of 207 Old 04-14-2006, 05:06 PM
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Quote:
Originally Posted by eh? View Post

I'm adjusting the red/green/blue sliders.

I adjust the sliders, and then take readings using the colorimeter tool setting the window at various grey levels (51, 51, 51; 76, 76,76; 102, 102, 102; etc) and input the readings for xyY and colour temp into the spreadsheet to track Gamma, Colour temp, and Delta E

The thing I have noticed is that the wizard sets you up with a colour profile which is near bang on for the gamma, but not so good on the Colour temp... mine usually comes in at around 6700 -

Setting up the monitor on my own, finding the right relative and absolute levels of RGB, using the sliders, I can get a much better overall colour temp (between 6400-6600)- but the gamma is slightly off (2.23 for red and green, 2.19 for blue)

Are you connected through VGA? When I connect through DVI, all monitor controls except Brightness is disabled. Are you talking about color bars on the monitor or the Video card display profile?
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post #119 of 207 Old 04-14-2006, 06:44 PM
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Connected through DVI - Under the "Color Settings" not under the "Image Settings" menu for the monitor.
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post #120 of 207 Old 04-14-2006, 06:51 PM
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Quote:
Originally Posted by Ursa View Post

Shawn - Looking at the sRGB specs, and trying to back into what some of the Rec709/SMPTE-C documentation says, seems to indicate to me that a gamma function is supposed to include the non-zero black level as part of the foundation for determining the theoretical gamma values. This was what Jeff was indicating. However, if Poynton is correct, then what you really want is for 99% stim to be JND* from 100%. Using CIE Luv, one could do a rough calculation of this (L*), but given the controversy over Delta E*, I'm not sure that this would necessarily produce a better answer than the analytical shorthand that Jeff (and I) use. It would certainly be more computationally intensive.

Alternatively, one could notice that when you normalize, you are usually using a fairly high number (reference white with my H77 runs between 400 and 500 cd/m^2). At that point, the 0.2 cd/m^2 black level is really a rounding error when we talk about normalization. If you use a curve-fit method (e.g., log-linear regression, preferably with >15 measurement points), then the rounding for black level and normalization pretty much get washed out.

So, basically start from 100% and calculate JND down to 0%, or go with a regression method to avoid having to measure a 0% value (even though it doesn't get used in most people's calculations other than to tweak the normalization process).

By the way, you should link directly to Poynton's site, rather than to a mirror. He's got some great stuff there that folks who are using your stuff ought to read.

Later,
Bill

* JND = Just Noticeable Difference

I'd strongly suggest anyone who is really trying to learn about color and calibration actually just buy Poynton's book. It is a great reference.

Yes, calibration is important...every user should be calibrated.

Need electronics repair? A great place to start looking for a shop in your area: http://www.tvrepairpros.com/
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