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Advanced LightSpace Operation

 
 
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Author Steve

Mod - Scene 
#1 | Posted: 30 Aug 2017 14:26 
We've added a new page to the Light Illusion website:

https://www.lightillusion.com/advanced_lightspace.html

This will detail some of the more advanced operational possibilities with LightSpace - and we're happy to add info on any specific areas users are interested in, so please post any requested in this thread.

Steve
Steve Shaw
Mob Boss at Light Illusion

Author RollsRoyce
User - Mono 
#2 | Posted: 20 Jan 2019 17:54 
Steve, I just followed the "Multi-Step LUT Calibration" process given in the advanced LightSpace guide you referenced. Our CRT TV has a gamut triangle that has slightly longer blue > red and blue > green arms but a shorter red > green arm than Rec709. Wow. I wasn't expecting much of a difference, if any, from a normal single-step LUT, but there sure is. I haven't yet run a verification profile, but visually, the results are terrific. Fleshtones are very natural, and blacks and shadows, particularly on surfaces that have a mixture of gloss and flat areas, are realistic. Colors are natural, as well. Amazing. Simply amazing.

Author Steve

Mod - Scene 
#3 | Posted: 21 Jan 2019 18:58 
Thanks - that is the intention of the open workflow capabilities of LightSpace - glad it's working well for you!
The Augmented Data process is also worth trying, as that will also help.

Steve
Steve Shaw
Mob Boss at Light Illusion

Author RollsRoyce
User - Mono 
#4 | Posted: 22 Jan 2019 00:19 | Edited by: RollsRoyce 
Actually, Steve, I did use an Augmented profile in creating the Multi-Step LUT. I do have a minor question, though. When running a verification profile on the final multi-step LUT, would one select the Source from the first LUT in the chain as the target color space, or the Source from the final?

Author Steve

Mod - Scene 
#5 | Posted: 22 Jan 2019 08:25 
You would always select the colour space the display is being calibrated to - Rec709 for example.

Steve
Steve Shaw
Mob Boss at Light Illusion

Author RollsRoyce
User - Mono 
#6 | Posted: 22 Jan 2019 13:14 
Great, thank you!

Author Steve

Mod - Scene 
#7 | Posted: 13 Jul 2019 10:10 | Edited by: Steve 
We've just added a 'Hint' capability to LightSpace XPT, PRO, and HTP.
(We have limited Hint to these licenses as the process really needs a high-end probe to be effective, due to the need to have a very accurate 'master/guide' profile.)

The Hint process enables small profiles, such as Quick Profiles, to provide calibration accuracy that is closer to the accuracy usually only attained via large volumetric profiles.

Information on 'Hint' can be found within the website 'Advanced LightSpace Operation' user guide: https://www.lightillusion.com/advanced_lightspace.html#hint

Steve
Steve Shaw
Mob Boss at Light Illusion

Author Steve

Mod - Scene 
#8 | Posted: 13 Jul 2019 10:25 | Edited by: Steve 
Another process we have been playing with for situations where probes struggle with low-light accuracy is the merging of 2 LUTs generated from 2 different profiles.

For example, using a 21^3 for all data above, say, 10 nits.
And a Grey only profile for below 10 nits.

One of the issues with large profile data sets is the inaccuracy of the readings when the probe is struggling with low-light readings.
Obviously 'colour' readings have less brightness than Grey Scale readings, so cause more inaccuracy in the final calibration LUT.
Using Grey Only data for the low-light range meas such 'read' errors are not included in the LUT generation.
But at higher brightness levels the full volumetric profile data is needs to accurately map the volumetric calibration.

To do such LUT merging the LUT image can be used, via a graphics program such as Photoshop.

https://www.lightillusion.com/lut_image.html

Basically you key through the low-luma range from the Grey Only generated LUT into the 21^3 generated LUT...

From this you can see how we can automated such capabilities within LightSpace/ColourSpace.

(Edited to add: See the 'Hybrid' mode post below...)

Steve
Steve Shaw
Mob Boss at Light Illusion

Author Steve

Mod - Scene 
#9 | Posted: 23 Jul 2019 09:03 
We've been thinking about the new Hint process, and with LG's concept of a 3-Matrix Calibration for WOLEDs we have plans for Hint (with some adjustment) that would enable it to be used for an advanced Probe Matching process, and provide a far more accurate method for probe matching than the existing FCCM or LG's 3-Matrix idea, especially for any non-additive displays and volumetrically non-linear displays, which WOLEDs obviously are.
(That does ignore the requirement for the Spectro to not suffer Metameric issues with WOLEDs, which is a whole other issue...)

We're also working on a new method to effectively extract different profile data from a large volumetric profile to enable different ares of the profile to be treated differently - which will be another real help with difficult displays, and when excessive changes are needed, such as with HDR.

This is another example of the flexibility of LightSpace enabling yet more options to be added.

Steve
Steve Shaw
Mob Boss at Light Illusion

Author Steve

Mod - Scene 
#10 | Posted: 26 Jul 2019 12:29 
We've just made a new Beta available with a new 'Hybrid' mode for LUT generation.

Hybrid mode is based on Peak Chroma, but does two things that can potentially help with the accuracy of the LUT's grey scale, and low-light performance, by isolating those areas of the profile, and processing them independently from the rest of the profile's volumetric data.

This maximises the accuracy of the grey scale, and helps remove low-light errors introduced by inaccurate probe readings.

Steve
Steve Shaw
Mob Boss at Light Illusion

Author RollsRoyce
User - Mono 
#11 | Posted: 20 Sep 2019 14:00 | Edited by: RollsRoyce 
I'm interested in the newly-introduced separate 1D and 3D LUT upload capability for Radiance. I assume one would use one of the GS profiling patch sequences to produce the 1D LUT for upload, followed by a large cube profile to produce the 3D LUT?

Author Steve

Mod - Scene 
#12 | Posted: 21 Sep 2019 09:16 | Edited by: Steve 
That is entirely down to your preference.
You can use a Grey Only profile, or anything else that can be used to generate a LUT.
But, you must perform the 1D first, and then the 3D, when doing them separately with a Lumagen.

See: https://www.lightillusion.com/lumagen_manual.html

Steve
Steve Shaw
Mob Boss at Light Illusion

Author RollsRoyce
User - Mono 
#13 | Posted: 24 Sep 2019 15:18 
Thank you. I intend to try it today, comparing it to another Radiance memory slot holding a LUT made via the concatenation process. I'll report back.

Author RollsRoyce
User - Mono 
#14 | Posted: 24 Sep 2019 17:55 
It worked exceptionally well. No obvious image quality issues, artifacts, etc. Switching from the memory with the concatenated 1D+3D LUT to this one and back again showed no major differences except for the concatenated LUT giving a touch lighter image in darker areas. I think this might be expected, as it targeted a 2.2 gamma while the new calibration was set for 2.3. The process is definitely less complex than generating a concatenated LUT.

Author Steve

Mod - Scene 
#15 | Posted: 25 Sep 2019 09:12 
Good news.
Glad all is working as expected.

Steve
Steve Shaw
Mob Boss at Light Illusion

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