Calibration for DLP Projectors? - Page 2  

People should definitely read your guide. It is very well done.

For DVI and HDMI inputs, an upscaling DVD player with Avia/DVE/etc can be used in place of a signal generator.

Below are the caveats:

The DVD player must output DVI at Video/Studio levels, not at PC levels. This eliminates the Samsung players which output PC levels. The Bravo D1 and Momitsu 880 match my Accupel's output

If the DVD player has Contrast/Brightness controls, they must be set to output 16/16/16 for Black and 235/235/235 for White. You would think that the stock settings would do that, but they often don't. For example the Brightness on the Oppo DVD player has to be set at +5.

Glenn

Right I had a problem when first tuning the Oppo, no moving black bars with Avia's all black/bars pattern. I think I'm at plus 4 for brightness, plus 1 for contrast. How do you determine when you're at 16/16/16, with the Accupel? What number did the device say for contrast?

For me, the biggest advantage with DVE are the patterns which show discrete steps close to and below black, and close to and above white. They allow one to set brightness and contrast with a very fine degree of certainty. These patterns are not available on AVIA.

DVE also has 6.75Mhz multibursts which can be used to ensure pixel perfect mapping. I need to check, but I'm not certain that AVIA goes that high in any of its test patterns.

Indeed, and keeping to the original discussion, the fact remains that AVIA contains the most basic of these patterns, which is not a surprise as it's the oldest of the discs, and that DVE has some patterns which are extremely useful when calibrating digital displays that simply do not exist on AVIA. It is also true, as you point out, that any of the discs can be used to calibrate any type of display; I never said otherwise - I simply stated that, and if it makes you happy I'll add the clarification, *IMO*, that DVE contains patterns which give it the edge over AVIA for digital displays.

Cheers,

Mark

Hi...I'm back...:D

Now that's clear. I can tell that my questions have started to become somewhat grating on you, and that is why I have decided to ask in open forum...to spread the annoyance around to others...:p

Great! Jeff recommended DVE Pro as well, so I guess $300 is a relatively inexpensive solution.

I kinda figured that. The performance/extra cost ratio is pretty good...:)

I bought my Firehawk material in May of this year, so I assume that I have the newer version. This is also a good example of why I thought that the screen had a grayscale of its own and that offscreen measurements would probably be more accurate when the levels are sufficient to measure properly.

Yes, Chris, I am using DVI output from a 6600GT on both HTPCs. I used 3no's patterns and the information provided by you, cyberbri, and 3no to get TheaterTek's VMR9 output to track as perfectly as possible.

That's basically what I figured. The HDNet patterns are broadcast for such a short time (and while I am working) that it makes it impossible to do any adjusting using them. My hope was that by capturing both the HDNet and InHD patterns, that playback through a properly calibrated HTPC outputting 720p (the same as my Dish 811) would at least give me something to use for adjusting PC HD playback, and would hopefully look relatively good with the Dish 811 as well. Once I buy the DVE Pro set, I should have enough patterns to do a little better job, right?

Hopefully, mine is...:) I used the procedures outlined in this thread:

http://www.avsforum.com/avs-vb/showthread.php?t=523614

from my neck of the forum...:D

Yup, read your guide, too!

I've got a Panny S97 with the latest firmware on its way here (It's the one that Kris Deering just tested for his latest report :) ). Is that one ok?

This statement is meaningless without some numbers. I'd like to see how repeatable the readings were and what the light levels were.

William,

I totally agree that is why I was suggesting 0.2 fL and 10 lux as the absolute minimum levels to attempt to read color. Those levels provide around a 10 to 1 signal to noise ratio for typical sources. Higher light levels definately add more confidence.

Ken was fooling around with the instrument. They seemed repeatable to about 0.005 to 0.002. The light level was about 10 lux at 0 IRE measuring about 2 feet from the projector lens. This is based on my memory since we did not record the values on his projector.

William I just took some measurements at light levels near what I am suggesting is the lower limit with my setup since you seem to like data as much as I do.

Eye One Pro

Sample Size: 11
Average x: 0.3251
Std. Dev. x: 0.0032
Average y: 0.3499
Std. Dev. y: 0.0012
Average Luminance: 0.2575 fL
Std. Dev. Lum.:0.006 fL
Average Correlated Color Temp: 5815K
Std. Dev. CCT: 140K

Modern Filter Based Color Analyzer Reading The Same Display

Sample Size: 11
Average x: 0.3158
Std. Dev. x: 0.0024
Average y: 0.3412
Std. Dev. y: 0.0035
Average Luminance: 0.2fL
Std. Dev. Lum.:0.0 fL
Average Correlated Color Temp: 6260K
Std. Dev. CCT: 95K

Which patterns on DVE do you use for contrast (for a digital projector)? Thanks. SJ

Title 12 Chapter 14 - Reverse Gray Ramps And Steps; is one of my favorites to look for color shifts at the top and bottom of range.

Title 12 Chapter 15 - Reverse Shallow Gray Ramps: is also very good at detecting color shifts with modern display technologies.

Ok, one more post full of stupid questions and I'm diving in:

1. When I measure the 3 primary and 3 secondary colors, do I do so using a full field of that color, or do I measure them from a 100% white field?
2. Do I need to even look at the color bars when profiling the DVI input of my projector? I assume that the color bars are used only for adjusting color decoding (if necessary), and that there is no actual measuring taking place, right? ANd since there is no decoding taking place with DVI, I don't need to bother with it.
3. When measuring "black" and "white", both Avia and DVE provide "black" fields, but neither provides a field labeled "white". I assume that I just use the field marked 100 IRE, right?

If these are all of the needed patterns, I have found that DVE lacks some of the necessary IRE fields for measuring, as DVE's IRE levels are in 20 IRE increments, while Avia provides 10 IRE increments

1. You need to have the color on the screen to measure it. You can do this with color bars if you are willing to accept possible contamination in exchange for speed.
2. I always check the color bars to make sure everything is setup properly. It is up to you if you do this step.
3. Black is 0%. White is what will be labeled white on the tristimulus chart. I use 75% color patterns so mine is 75%. You can use whatever you like, but I would avoid 100% anything for the tristimulus chart to avoid problems with panel saturation on secondaries and white.

3)Yes, fields labeled 100IRE are reference white, or level 235.

The patterns mentioned just above on DVE, T12 chps 14-15 contain material both below black, and above reference white. Avia has white and black and in between only. Avia PRO has way too much of everything! ;)


1) If you are measuring and adjusting the primaries or secondaries, you would be measuring off a color field, or you'd measure white of course!

2) Color bars yes are for color decoding, you would adjust the paramaters where this decoding was taking place, which if you are using VGA/RGB output from your HTPC or DVI output (or HDMI set to RGB) then you would adjust this at the HTPC, lkely the controls within Theatertek, for instance. If you are outputting component video or something like that, then it would be elsewhere in the chain, most likely at the display. Yes you should always check colorbars to make sure the color decoding is aligned correctly,even if you are outputting already decoded RGB. From an HTPC it should be right on with default settings with neutral settings, but it could be off, so always check it's a fast check only takes a moment. I think in earlier TT updates you had to really adjust things pretty far for correct output, but that has been fixed, so it should be spot-on decoded output from the get-go. There's no video attribute that *isn't* worth checking!

I hope that helps! Your questions are all quite relevant and well-informed!

Thanks, guys...I'll be back!

Is that a threat?

j/k :D

It might be. ;)

No, it's a promise!

Ok, here's the results of my first test. I profiled my 7210's DVI input with TheaterTek 2.1.1 using VMR9, properly calibrated to 16,16,16 and 235,235,235 (I hope ). All settings on the 7210 were out of box defaults, except for the RGB gains/offsets, which are recommended to be set as 66/39 as a starting point for this projector. Gamma was set to film and brightness and contrast were tweaked slightly from the default 50/50 settings using the reverse ramps from DVE. I took all reading off the screen, so I will assume for now that that would explain the terrible results below 30 IRE.

I have attached JPEGs of the results screen so that anyone interested can view them. My next step will be to learn how to interpret these results before screwing things up...

There is some gamma processing going on in TheaterTek or VMR9 - I always get around 2.2 for film, 2.5 for CRT.

You have burned in some hours and drained red already - but normally green and blue are about the same when that happens. I think you must have the old FireHawk that was a bit blue?

Your contrast is about what I got though - so 1700:1 maybe is the norm?

Did you get the stuff for reading the projector with the Beamer? Be interesting to see the greyscale there.

Bob your light levels are crazy low. How far from the screen did you measure those? You need to be close enough that the Eye-One is only seeing the illuminated screen.

Bob,

Did you have the diffuser on when you measured the screen? That would have caused the measurements to read low as well.

I have the EyeOne mounted on a tripod at about a 45 degree anglee poited upwards (so that the body of the EyeOne did not cause shadows). The distance from the sensor to the screen (at this angle) was 7 inches...too far?

No, I couldn't mount both the diffuser and the holder at the same time. It was an either/or proposition, so I chose the holder and pointed it at the screen.

Hmmm....Yes, I see. The 7210 in an incredibly bright projector, and 5.756 ftL at 100 IRE just isn't right. Maybe I was both too far and the Firehawk doesn't like the 45 degree angle?

The viewing cone is rather narrow on the FireHawk - go off 45 degrees and see with your own eyes! The half gain is at 24-28 degrees off normal.

Do you mean the "Match" software? Yes, I have the complete package, but I haven't as much as looked at the Match software as yet.

I meant the diffuser. umr said that was something the Pro version had over the Milori version.

Yup, I have the diffuser. The problem is that I can't put the diffuser on and then mount the EyeOne in its holder. I could probably get the job done with duct tape, though...:D

ColorFacts has an AIM mode where you display a 100 IRE window and adjust the sensor position while taking continuous readings until you get the brightest reading from the screen. Perhaps you could do something similar prior to measuring?

Mark

I would put the software in Multi Sample mode and move the instrument around until you get a measurement that is more believable. I would take it off the tripod so it is easier to move around as well.

The diffuser does not work with the holder. This instrument is very light so a tripod is not a requirement.