Flanders Scientific were the first to request we look into a better method for Probe Matching, for displays that are not 3 colour additive - specifically LG WOLED screens - where the existing Four Colour Matrix Method (FCMM) really doesn't work.

The unique 'Multi-point Volumetric Probe Matching' within LightSpace is the result, and Flanders (FSI) have been testing this extensively, and are seeing some serious improvements, even with very small volumetric matches.

Hi Steve,

Seems a tiny display characterization does wonders compared to Four Color Matrix Method.

What first alerted us to the need for something beyond FCMM years ago was seeing spectroradiometers and colorimeters with matrices from those same spectros disagree on certain colors (e.g. Yellow) by more than 0.003 for x or y chromaticity when measuring WRGB OLEDs. Since probes are typically rated with an accuracy of +-0.0015 for x or y we generally accept any agreement within a spread of 0.003 as acceptable, but we had deviations nearly double that range when testing some colors.

We repeated that testing comparing FCMM vs CR250. We again had a few colors, the same as in original testing, easily go over 0.003 difference in x or y. We've highlighted those in our spreadsheet.

We then did a volumetric probe match using a very small 3x3x3 display characterization and retested the same test patch set when done. Deviations are now well within our accepted tolerances. Maybe a somewhat larger characterization would work better, but we are so well within tolerance already that we don't see any reason to go to larger volumetric sets for matching.

The results attached are using Memory Color + Secondaries as the verification set for both the FCMM and the Volumetric probe match settings.

Thanks!

Bram Desmet

We have had a very nice comment form Colorimery Research regarding the unique unique 'Multi-point Volumetric Probe Matching' within LightSpace:

Steve, Bram sent me the results on the testing he did on LightSpace volumetric correction. Results are very impressive, congratulations!

I have done some testing of volumetric on my E8.
I have done that on tu configurations:
1) Jeti 1501, I1D3
2) Jeti 1501, Klein K-10 (i.e. SF)

The approach I have used was:
1) Measure for corrections based on the native (wide) gamut of my E8
2) Validate the correction in the same scenario
3)Test the corrections on a Rec.709 Gamut previously generated with LS.

For all verifications I have measured the distance from Jeti to the corrected probe, both in math terms (i.e. %dY - normalised on 255,255,255 for easier comparison, dx, dy, dxy) and perceptive terms (dE2000). 1000 (10^3) patches have been used for testing.

Here also a snapshot of primary and secondary colour
For I1D3 down to 193 level

For Klein down to 163 level


As you can note outcomes indicates that the couple I1D3/Jeti benefitsfrom volumetric, whilest the Klein/Jeti doesn't. Of course on my E8.

You can have a look to the whole comparison files and play with them at the following:
I1D3:
https://www.avsforum.com/forum/attachment.php?attachmentid=2669398&stc=1&d=1578940879
Klein:
https://www.avsforum.com/forum/attachment.php?attachmentid=2669396&stc=1&d=1578940879