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post #151 of 166 Old 04-12-2013, 04:02 AM
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Quote:
Originally Posted by Chad B View Post

I put in a question to Tom in the CP thread to see if the triplets I use here will give correct results with ChromaPure.

Thanks, its all a little out of my current realm of knowledge smile.gif

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post #152 of 166 Old 04-12-2013, 06:38 AM
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Quote:
Originally Posted by Chad B View Post

I put in a question to Tom in the CP thread to see if the triplets I use here will give correct results with ChromaPure.

Think I get what I read in the CP thread. Correct me if I am wrong.. When patterns are created with the real generators, they are done at whatever gamma you have chosen. So are your patterns 2.2 or 2.22 or am I misunderstanding what tom said? This issue with gamma is only for the color patterns and not Gray scale, correct??
Thanks!
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post #153 of 166 Old 04-12-2013, 06:59 AM - Thread Starter
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Quote:
Originally Posted by airscapes View Post

Think I get what I read in the CP thread. Correct me if I am wrong.. When patterns are created with the real generators, they are done at whatever gamma you have chosen. So are your patterns 2.2 or 2.22 or am I misunderstanding what tom said? This issue with gamma is only for the color patterns and not Gray scale, correct??
Thanks!
OK, this is what I have gleaned from Tom's explanation and from using the 2 programs:

CP has fixed reduced sat target points. In CP, the triplet (color/intensity of the pattern) is changed according to your target gamma.

In CM V5 the reduced sat target points are changed according to your target gamma. The triplets are fixed no matter what gamma is used/targeted.

The triplets I used in these patterns are what CM V5 expects to see when you select "75% sat only" at 75% level no matter what gamma you target. They are very close to what CP expects at 2.2 gamma, but in order to really nail it I am going to have to make some new patterns for CP.

The triplets I used are:
R 165,60,60
G 77,176,77
B 58,58,123
C 95,176,176
M 156,77,156
Y 178,178,88

0-16
10-38
20-60
30-82
40-104
50-126
etc
I am going to ask Joel to verify this.
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post #154 of 166 Old 04-12-2013, 07:07 AM
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Thanks Chad. I used Masciolas disc last night on my VT for the 6.5% patterns, and since I have chromapure. When my calman rig arrives this weekend I intend on using your pattern disc since its modeled for a calman calibration. I did some measurements yesterday as found in custom. The differences between your 4% circles and his 6.5 and 10% windows were minor.

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post #155 of 166 Old 04-12-2013, 08:10 AM
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Quote:
Originally Posted by Chad B View Post

CP has fixed reduced sat target points. In CP, the triplet (color/intensity of the pattern) is changed according to your target gamma.

In CM V5 the reduced sat target points are changed according to your target gamma. The triplets are fixed no matter what gamma is used/targeted.

That's correct.

We used to recalculate the triplets early in the CalMAN 5 beta but changed it as it neared release. The reason was that if you changed the gamma (especially with something like BT.1886 that dynamically adjusts based on black level), then none of your measurements would be valid. So by fixing the triplets and recalculating the targets, the readings are always valid, but their targets may shift a bit, but at least the data is always correct.

You can see the triplets we show in CalMAN by adding the triplets into the data grid.

The one time we do change the triplets is when change the actual gamut size (rec.709->SMPTE-C->DCI).
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post #156 of 166 Old 04-12-2013, 10:45 AM
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One other thing to note, is we round our RGB to % so as to keep compatibility with pattern generators that only support RGB percent (DVDO DUO I'm looking at you).
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post #157 of 166 Old 04-14-2013, 11:32 PM
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Quote:
Originally Posted by airscapes View Post

Think I get what I read in the CP thread. Correct me if I am wrong.. When patterns are created with the real generators, they are done at whatever gamma you have chosen. So are your patterns 2.2 or 2.22 or am I misunderstanding what tom said? This issue with gamma is only for the color patterns and not Gray scale, correct??
Thanks!
Gamma has nothing to do with the signal generator. The signal generator simply outputs a mix of RGB in 8 or 10-bit precision as instructed. Gamma comes into play in the software. If the user selects a 2.2 gamma for, say, 75% intensity, 75% saturation red, then it will instruct the signal generator to output slightly different RGB triplets than if 2.4 had been selected. Alternatively, you can keep the test patterns the same but change the CIE xyY targets as the gamma changes. I prefer the former approach, since 75% saturation seems to me to mean a fixed point in the color space.

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post #158 of 166 Old 04-15-2013, 12:05 AM
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Tom

Why 2.2 and 2.22?

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post #159 of 166 Old 04-15-2013, 06:21 PM
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Quote:
Originally Posted by JimP View Post

Tom

Why 2.2 and 2.22?
I am not sure exactly what you are asking.

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post #160 of 166 Old 04-15-2013, 07:11 PM
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Quote:
Originally Posted by TomHuffman View Post

I am not sure exactly what you are asking.

They're close together. Seems that you'd have one or the other but not both as gamma options.

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post #161 of 166 Old 04-15-2013, 07:25 PM
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Quote:
Originally Posted by JimP View Post

They're close together. Seems that you'd have one or the other but not both as gamma options.
The more options the better.

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post #162 of 166 Old 05-27-2013, 02:37 PM
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Just went through this thread. Got really quiet for the last month ....

Is my thinking that the current version 2 is NOT correct to be used in ChromaPure but OK for CallMAN?

And, is there any one place where how to use these patterns is printable?
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post #163 of 166 Old 05-27-2013, 02:44 PM - Thread Starter
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Yes, they are all bit perfect for CalMAN but the reduced saturation patterns are very slightly off for ChromaPure.

There's no all in one guide as of yet.
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post #164 of 166 Old 05-28-2013, 01:08 PM
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I downloaded the APL 4% windows with pluge using the link above (http://www.avsforum.com/attachments/65583).

The image file "type" for stimulus measurement levels 70% and 90% differs slightly from that for the others. "apl9_ 70.png" and "apl9_ 90.png" each have an alpha channel whereas the others do not. It might be a good idea to remove the alpha channel for maximum consistency since not all programs handle transparency correctly.

I discovered this when analyzing the files in Mathematica. I wanted to check the APL value for each pattern and got an odd result for those two files. In case it is of interest, this is the function I have now defined to calculate APL values:

P[x_] := (100/219) (255 Mean[Mean[Mean[ImageData[RemoveAlphaChannel[Import[x]]]]]] - 16)

The function P[x] calculates the APL value for image file x. The list of {centre circle stimulus, APL} value pairs for files "apl9_10.png" to "apl9_w100.png":


{
{10, 18.7545},
{20, 18.7545},
{30, 18.7545},
{40, 18.7545},
{50, 18.7545},
{60, 18.7545},
{70, 18.739},
{80, 18.7545},
{90, 18.739},
{100,18.7545}
}


There appears to remain a small discrepancy for the two files mentioned above.

Cheers.
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post #165 of 166 Old 05-29-2013, 11:24 AM
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I've had a closer look at the patterns I referred to before. There are the following inconsistencies in the pattern set for stimulus levels 70% and 90%:

In the 'apl9_70.png' pattern the 70% stim disc has greyscale value 169. In the other patterns it is 170.

In the 'apl9_90.png' pattern the 90% stim disc has greyscale value 213. In the other patterns it is 214.

Consequently, the patterns do not have the same APL, although the variation might not be considered significant.
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post #166 of 166 Old 08-26-2014, 11:45 AM
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Quote:
Originally Posted by chunon View Post
<div class="quote-container" data-huddler-embed="/t/1445226/chad-bs-custom-test-patterns/120#post_23093480" data-huddler-embed-placeholder="false"><span>Quote:</span>
<div class="quote-block">Originally Posted by <strong>airscapes</strong> <a href="/t/1445226/chad-bs-custom-test-patterns/120#post_23093480"><img alt="View Post" class="inlineimg" src="/img/forum/go_quote.gif"></a><br><br>
Here is the latest version, Chad can you update the the first post when you get a chance.<br><a class="bbcode_url" href="http://misc.airscapesart.com/chadb/chads_patterns_v2.ios" target="_blank">Chads Patterns Version 2 AVCHD ISO</a></div>
</div>
<br>
Appreciate it sir I will be trying these out very soon <img alt="smile.gif" class="bbcode_smiley" src="http://files.avsforum.com/images/smilies/smile.gif">
Link is not working.

Does anyone have a current link to these patterns? I've searched and come up empty.

Thanks.
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