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Discussion Starter #1
I'm very pleased to announce the release of ArgyllCMS V1.7.0.

The highlights in this release are:
  • Support for DataColor Spyder 5 & Klein K10-A colorimeter.
  • Added Google ChromeCast as a test patch generator for Video displays.
  • Added X3D and X3DOM support as an alternative to VRML, and make X3DOM the default for the viewing of gamuts in 3D.
  • Fix various instrument communications problems for JETI specbos, DTP92 & DTP94.
  • Numerous other improvements and fixes.

For a longer list see

As always for the downloads.

Graeme Gill.
 

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For those interested in using the Chromecast pattern generator functionality of version 1.7, it provides a Y'CC output and there are rounding errors associated with it's conversion of the R'G'B' triplets used to address it. For this reason Graeme has dithered the device output to minimize these rounding errors. I've done a couple of tests to assess the effectiveness of the dithering. First by measuring all 256 neutral levels and comparing that to my laptop generated response, which provides perfect triplets. By comparing the difference in measured output at each level I can calculate the LSB offset between "truth" and the Chromecast output. Using this technique I can measure differences with close to 11 bit precision.

Dithered vs. raw output


The effect of the dithering is to knock down the peak errors but it also adds noise to those levels which were ok to begin with. However, the net effect is beneficial if the residual noise can be confined to 1 LSB, the 1-sigma level of residual noise was measured at 0.33 LSB.

The other test I performed was a practical one to see how well the device performs in an actual calibration. So I ran DCG using the Chromecast as pattern generator in a standard auto-mode configuration for eeColor LUT calibration, and then ran a verification test using laptop generated patterns. The results are here. The average dE00 value is within 0.1 of what I can obtain using a perfect generator (max within 0.5 dE00), so for practical usage you'll get excellent results.

 

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The average dE00 value is within 0.1 of what I can obtain using a perfect generator (max within 0.5 dE00), so for practical usage you'll get excellent results.
Thanks, good to know, hit might well be worth it to avoid display driver settings related pitfalls.
 

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Discussion Starter #6
Dear Graeme!
You can add in argyllcms 1.7.1 change integration time for meters?
Most meters use adaptive integration time by default, so there is no particular integration time to change.

But what specific problem are you trying to solve ?
 

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I want to be able to choose to compare different variants with my meter.
Still need a function manual choose syncro refresh, but not auto.
 

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On the topic of integration time, I've been wondering if it's possible to extend the maximum integration time of the i1d3 to an arbitrary value. Presumably this would enable even lower luminance readings. Is it an issue of heat build up and noise with excessive read times?
 

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Discussion Starter #9 (Edited)
I want to be able to choose to compare different variants with my meter.
That's a lot of work and extra complexity in the code, UI & documentation, just so you can play around.

If there is a demonstrable problem, I'll address it. Otherwise, the source code is available and isn't too hard to compile if you're keen to experiment.

Still need a function manual choose syncro refresh, but not auto.
Why is that ? What problems do you have with the normal detection of the refresh rate ?
 

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Discussion Starter #10
On the topic of integration time, I've been wondering if it's possible to extend the maximum integration time of the i1d3 to an arbitrary value. Presumably this would enable even lower luminance readings. Is it an issue of heat build up and noise with excessive read times?
It's not possible within a single reading, because the hardware imposes a maximum time of 20 seconds. Taking multiple readings wouldn't help much, as you can't measure a frequency when zero or one transition occur in the 20 seconds. You need at least two transitions, meaning that the lowest measurable frequency is 0.05Hz. (The L2F sensor may start to have poor linearity and/or be reaching its black limits below 0.05 Hz anyway).
 

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That's a shame. I was thinking it could operate similarly to the way a CMOS or CCD camera sensor works, where radiance and time can be traded equally.
 

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Discussion Starter #12
That's a shame. I was thinking it could operate similarly to the way a CMOS or CCD camera sensor works, where radiance and time can be traded equally.
The cheap end of the colorimeters all seem to use the L2F sensors. They have in built temperature compensated black zero, and are cheap to interface - you just need a crystal oscillator as a reference. Only the more expensive end (and the older DTP92/94) use a sensor + A/D, and black drift tends to be more of an issue unless some effort is used to counter it. The i1d3 gets a boost from its light concentrating optics and really nice filters. So pretty much you get what you pay for.
 

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Quote lightillusion:

"The integration time of the i1 Display Pro depends on your display type and display setup and can be any value between 0.25 secs - 3 secs. As a general rule of thumb, a value around 2 secs is a good average max – 3 secs tends to over-saturate the probe. On most displays the ideal integration time will fall between 1.5 secs - 1.8 secs.

In order to find the best integration time of the i1D3 on the display that is going to be profiled, you need to measure a series of patches and determine an integration time that is a good compromise between getting stable readings on the darkest patch and not over-saturating the probe on the brightest patches.

The "darkest patch" - that your i1D3 probe is able to read on your display - can vary and depends on the display type and the display setup. On LCDs with generally less darker blacks, your i1D3 might be able to read full black while on Plasmas with deeper black values your i1D3 might not achieve a reading of full black. In addition, the gamma setting on the display can further change the darkest patch the i1D3 is able to read.

The series of patches to be measured should include full black, very low brightness patches as well as patches with higher brightness values. Measure the darker patches first and increase the integration time (in small increments) until the darkest patch the i1D3 is able to read returns stable readings. A "stable reading" is a reading that the probe can repeat when continuously reading the same patch. Keep in mind that the i1D3's repeatability is pretty good but not perfect, so if continuous readings on the same patch have minor variations that would still be considered "stable".

For Plasma displays the integration time (ideally) needs to be a (large integer) multiple of the PWM frequency (refresh rate). Use this tool to calculate suitable integration times:

Variable integer Plasma PWM frequency (refresh rate) Hz | Integration Time: 1.56 secs


Your goal is to find the shortest integration time that provides stable readings on the darkest patch - you do not want to choose a longer-than-necessary integration time because that could potentially over-saturate the probe on readings of brighter patches. Find an integration time that is a good compromise between achieving stable readings on the darkest patch, yet not over-saturating the probe on brighter patches."



That is why i want manual choose integration time!
 

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Discussion Starter #14

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Hi,

could anyone please upload the installer for Windows 64 bit somewhere? I haven't been able to download the software for days, the download from the homepage seems to be very slowly and gets aborted after a short time.

Thanks!
 

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Dear Graeme!
Why my meter - Colormunki Design not support display type LCD(generic) Adaptive HiRes?
Display type ignored - instrument doesn't support display type selection ?

Setting up the instrument
2015-05-25 21:48:12,260 Instrument Type: ColorMunki
2015-05-25 21:48:12,260 Serial Number: 1008964
2015-05-25 21:48:12,262 Firmware version: 288
2015-05-25 21:48:12,263 Chip ID: 01-EA5C9A14000041
2015-05-25 21:48:12,263 Version string: 'colormunki FW V1.32 Build Nr. 1303'
2015-05-25 21:48:12,263 Calibration Ver.: 6
2015-05-25 21:48:12,265 Production No.: 70893
2015-05-25 21:48:12,438 Display type ignored - instrument doesn't support display type selection
2015-05-25 21:48:13,158 Created MadVR window


Only colorimeter support Display type?
 

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Colorimeters use display type settings to hint a device to what the spectral distribution of display may look like.

Since spectros read the spectrum directly they don't need per display type correction.
 
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