Radiance 3D LUT (5x5x5 Cube) Calibration with CalMAN 5 - Page 2

Will 3D LUT calibration make post gamut calibration adjustments of the color and tint control with blue filter etc.. a thing of the past or are these fine tuning adjustments still necessary ?

A total thing of the past.

The blue filter and visual touch up post cal is done based on all of the problems you can get when your display has a funky color decoder or isn't completely linear. Since those issues don't show up in a basic gamut sweep. Since this process looks at so many more intermediate values, it eliminates the need for post cal tweaks.

So, are you saying that the cube itself contains the grayscale (0-100%, 21 steps) already? I am not sure I understand what you mean by do grayscale with the cube in unity, then calibrate the cube.

An oversimplified view of the video path basically goes like this.

HDMI in -> Cube 3D LUT -> Ramps 1D Lut -> HDMI Out

The cube covers literally every single RGB triplet, so everything after the cube is no longer at reference values anymore. Things that aren't at reference values can't be calibrated correctly.

So you reset the cube to default (unity), so that you have a clean path to the 1D LUT. Basically this is like calibrating the display before you calibrate the radiance. Just one step further. Calibrate the TV with reference patterns. Calibrate the 1D LUTs in the radiance, Calibrate the 3D LUT.

The CalMAN workflow for building 3D LUTS already handles this correctly, by forcing a 3D LUT reset before doing a 1D Ramps AutoCal.

I'd like to see how it'll perform with displays that have an agressive ABL system. Theory is nice, but I'd think ABL would be a problem.

It will help it as much as it can.

Using the small windows in the radiance keeps it off the ABL as much as possible. For the most part even as the limiters kick in, inter-scene gamma doesn't change much, as long as thing go up and down in a uniform way total light output

There is only so much you can do, if a system is too intrusive, then the display is fundamentally broken.

Because the same main GPU is used on all them.

Ah... so, we will do the grayscale autocal first, then 3D LUT autocal, and then we should not go back and redo grayscale, as it is not valid anymore. Is this what you are saying?
Also, When you say reseting the 3D LUT, does it remember the setting and apply itself back after we do the 1D ramp?

Usually, after doing grayscale and CMS, we will go back and forth a few times (and check brightness/contrast) to make sure things still look OK. Is this not recommended anymore?

You don't go back and forth anymore.
The 3D Lut gives us enough fine control and it completely encompasses the gamut, so we are adjusting and measuring EVERYTHING during the cube. If you want to tweak a point or two in the cube afterwards that's about all you can do.

Will the Radiance Mini (or any other Radiance for that matter) be able to hold a Cube 3D LUT in every memory slot ?
I looks like it will take a far greater amount of memory than the "old" CMS did.

I haven't seen anything to suggest that each one of the 8 CMS slots cannot be different....

I'm on the fence about upgrading to one of the eShift JVCs this year from an RS50. If I choose to keep the latter is the new 3D LUT Cube auto-calibration technology capable of dealing with it as fine and giving it as great a picture.... say 95% or higher of the finished result, as having one of the great professionals like UMR do the manual calibration and dealing with the wonky on board CMS and gamma issues of this unit? Since the CMS is not being used?

And having the Lumagen in line of course I realize that. Would do the Mini 3D if I did it.
Edited by RonF - 9/9/12 at 9:00am

The 3D LUT will absolutely take care of wonky CMS issues with JVC projectors. It can solve problems that otherwise cannot be solved.

But to get the most out of calibration, you're still going to want to optimize the projector first, a skilled calibrator is going to do that for you.

So in a lot of ways both getting a lumagen and hiring pro calibrator would be a great way to go. Make sure your Calibrator has CalMAN 5 Professional or Ultimate (Pro products with cube support). Before cubes any great calibrator could get the same results with any software package or even just reading the x,y,Y values off the back of the meter. But since calibrating cubes manually is prohibitively time consuming even the Pro's will have to rely on AutoCal, and the software used is going to make a difference on the results.

It has already been calibrated and then touched up a year apart by UMR, on a specific lamp now at 80 hours, which I then pull out and save for demos only with something I'm working on. He has his own proprietary software and the picture is spectacular. Even the new lamps put back in at those similar hours look pretty damn good though they were not the ones calibrated. It's the accumulation of hours on my every day lamps with this older design of bulb (at least pre-flap thingy....which doesn't sound like it solved their problem....as 2013 they went to NSH lamps and new power supplies)...... that if I stay with this projector another year and with future projectors.....I would do more frequent calibrations on.

The gamma and white balance shifts are what I would want to keep looking great. The wonkiness of gamma adjustment from the RS50 CMS is not an issue with this technology in conjunction with the Lumagen?

Yes the lumagen mitigates the issues with trying to get the JVC gamma set precisely. The issues with the JVC are due to the fact that their LUT points only line up wit the input levels at specific settings for brightness and contrast. This is not an issue with the lumagen, and you can drop the lumagen infront of the projector and be able to reliably and easily dial in gamma.

But did I understand you before that to get best results, a pro priced human calibration would still have to be done the first time on any particular lamp with the Lumagen, and then the auto features are good going forward? You can't get that same optimum level from starting with the the auto cal, after first setting contrast and brightness with S & M type disc?

I don't know about for a bulb replacement.

I was saying that for a first time setup having someone who can properly evaluate the projector is important (It could be you, it could be a pro). Having the projector calibrated to D65 is important. Adjusting the color space/gamut settings on the projector is important. You don't want posterization or banding in the projector, otherwise the cube may simply exacerbate the issues. So the first time setup is very important getting all the mode, color format, and basic settings dialed in needs someone who can pay attention to all those details for Pro level results. After all of the correct settings have been confirmed, the rest is going to be a fairly automated process,.

None of this is to say the process won't simply work without a pro cal first.

But perhaps you'll get a tiny bit of posterization, or other slight artifacts that could be solved by tweaking a setting or two.


Also that is the kind of service you'd get only from a very high-end calibrator or is something you could solve yourself if you're willing to put in the time to learn and experiment.

You'll get GREAT results from simply following our 3D LUT creation workflow.

Could a Pro eek out a subjectively better picture?
Most likely, but the subtle differences wouldn't even show up in the calibration report. It's stuff like posterization and banding that only shows up by subjectively looking at the calibrated result.

For someone who's more interested in visible improvements than ultra-precise measurement results, and isn't super picky about color accuracy, would the 3D LUT give appreciable perceptible improvement over a current Radiance calibration?

Yes, the current calibration, ultra precise results measured at 8 points doesn't really tell you much. Ultra-precise measurements tells you much more about your picture when you're measuring 125 points.

Using the cube only improves calibration, but it does only effect color accuracy.

It doesn't improve motion accuracy, resolution, or remove banding or posterization that already in the display.
Edited by sotti - 9/9/12 at 2:13pm

Joel,

What is the definition 'posterization"?

Example: http://en.wikipedia.org/wiki/File:Posterization_example.jpg

Thanks Joel... I thought that was "banding"

The Radiance can make the RS45/55/65 essentially "perfect" (small residual errors). However, the 55/65 are a bit dimmer for 3D than I'd want to live with. There IS some pretty good/impressive 3D out there but it's let-down when the projector can't make images that measure at least 4 fL for 100% white in 3D mode (measured through 1 lens of the glasses) and the 55/65 won't get that bright. If the next models are brighter, they'd be a better value for anyone interested in even occasional 3D. If you have a screen with 1.4 or higher gain, the 3D dimness is less of an issue for the 55/65. I haven't seen a 45 in 3D mode so can't comment on that model.

Thanks for your thoughts Doug. I'm concerned in this discussion with high FL 2D performance in talking about the JVC's. Unless some other rookie, however eager to learn, starting from scratch......is successful in getting very good to great automated calibrations with the 5x5 Cube concept firmware from Lumagen......without also having to have a Pro still come in for the $450-500 for "fool proofing" the whole auto experience, then I feel it is too expensive a gamble for me. Much as I would like to optimize my gear every 100 hours or so I can do it for less, buying a demo lamp and keeping it perfect with also decent performance on my everyday lamps as a byproduct. I have experienced this with my UMR demo lamp calibrated RS50. The everyday lamps look pretty damn good though they were not the lamp calibrated. I can dial the everyday lamps best as can be by my own eyes for my every day watching.

With the lesser price and much more steady and subtle drop in lumens described for the new JVC NSH direct current technology lamps......that seems a viable option for me is where my thoughts are now after the discussion above from both software camps. Versus $2,500+ for the all bells and whistles Mini 3D / auto cal software and meter package plus still having a Pro come in. However, if I start reading others achieving high end results as "newcomers" to calibration, without paying also for the Pro to come in, then definitely it will catch my attention.

Hi,

I'm about to purchase a Lumagen, have a few questions regarding the Lumagen 125 point / Calman auto calibration workflow:

1) how does Calman control the Lumagen ?

2) is the 125 point auto control available in the latest Calman 4 or is this Calman 5 ONLY ?

3) although I'm sure the integrated Lumagen calibration patterns are superb, wouldn't it be still be preferred to calibrate with patterns coming from a specific input signal source, e.g. a calibration disc inside a Blu-Ray player ? Is that possible with Calman and the Lumagen auto calibration and what is the workflow (automated control setup etc.) for this scenario ?

Thanks.

- M

1) Serial
2) 125 Point in v5 Only - You need CalMAN v5 Enthusiast or the Professional versions
3) You will want to check using your BR player and some patterns and/or reference material after the calibration is done... manually controlling all those patterns would take time..

1) via a RS-232 serial port on the back of the lumagen.
2) It's only a CalMAN 5 feature. It leverages almost all of the new features of our colorspace engine.
3) No, you'd only use the internal patterns. Trying to calibrate with a disc player would be ineffective and overly time consuming.

We have a specific Workflow in CalMAN 5 that walks you through calibrating 3D LUTS. The process is dial in the display, AutoCal the grayscale, AutoCal the cube.

@ turbe & sotti: thank you for your detailed responses !

yeah, i know i would take some time going through an 125 calibration even with an automated controlled blu-ray player with a disc inside, but I think this is the only way to accommodate for the specific signal distortion that specific device might have...

not everybody is using an Oppo who can be setup to just pass through the signal... ;-)

Thanks again.

- M

3. Here is one more reason to use a dedicated pattern generator/video processor as the reference source when calibrating your display as opposed to relying solely on a blu-ray or DVD player:
http://www.hometheaterhifi.com/secrets-blu-ray-player-hdmi-benchmark/secrets-blu-ray-player-hdmi-benchmark/blu-ray-player-hdmi-benchmark-introduction.html
This article points out some of the known issues with optical players and why it's recommended to use something more than a DVD/Blu-ray player as the reference source to optimize your video.

I hope this helps.