Setting up projector macros for 3d

You may need technician privileges in order to do this – consult your service provider or give us a call

If the projector is set to the 3D mode, the glasses should function and provide a stereoscopic image. However, unless the projector’s Dark Time and Reference Delay times are properly set the image will be less than optimal. These settings are adjusted on the projector’s 3Dcontrol panel. A typical 3DControl window is shown below.

1. Log on to your projector with “engineer” rights
2. Ensure that the projector has an appropriate pcf file for Active Glasses 3d.  This will be typically 185_YCxCz or 235_YCxCz. 
3. Assign two new macros, one for each ratio of 3D
4. Assign the apt pcf files for these macros.  At this stage use the existing 2D geometry files
5. Build a new Extra file for 3D.  Name this “active3d_extra” or similar
6. In the apt extra file, set the following variables for proper 3D operation

•Frame Rate: 4:2 for double flash, 6:2 for triple flash (use Triple flash)
•L/R Input Reference: Use active data port: Port A = Left; Port B = Right
•Input Frame Dominance: Left
•L/R input Reference GPI: None
•L/R Display Reference: Not Used
•L/R Display Reference: None
•L/R Output Reference Polarity: Inverted (change if the 3D image appears reversed)
•L/R Output Reference GPO: GPO 1
•Dark Time: 400 - 500 µsec for double flash, 700 - 800 µsec for triple flash
•Output Reference Delay: -100 µsec for double flash, -200 µsec for triple flash (note: these are negative values)
•Output Reference Phase: 0 deg.  You should just be able to set these parameters and forget them but it is advisable to view some actual 3D non-deghosted footage to insure that ghosting is not present. If it is, adjust the Output Reference Delay to minimize them. This is most easily done by freezing the image and then adjusting the delay time to minimize the ghost. If the delay time is set at -100 µsec, try increasing it in increments of -100 µsec. If the ghost gets worse go the other direction.

If the movie is being triple flashed as Disney often requires, a second problem, colour banding or posterizaton, can occur. This will be evident in large mid-tone areas that slowly transition from one shade of gray or colour to another. Instead of being continuous, the transition will be in steps or bands. This occurs because, while the lenses of the glasses go to the opaque state very rapidly, the transition to the transparent state occurs slowly enough that it takes a significant portion of the frame interval. Normally this would just result in a small decrease in brightness, but, because of the way a DLP projector modulates light, there can also be a reduction of colour depth. The solution is to increase the dark time so the lens has more time to open before the frame is displayed and to make the delay time more negative so the lens starts opening earlier – again allowing it to more fully open before the frame starts. There are limits to how far these parameters can be pushed, however. If the dark time is increased too much, the picture can become unstable and begin to break up along the top. If the delay time is increased too much, ghosting will occur. On the projectors that we were able to test, the values listed above provided an excellent compromise.

7. Now run some 3D footage.  You don’t need to have the 3d kit installed at this stage.  Check
1. The image geometry – typically you will need to set new lens or scaling files to zoom 3d up a little from the 2d image
2. The colours.  Make sure the correct pcf file is being used – if not, the image can appear to be missing the red information
3. Make sure both 3d signals are present – you should see a ghosted image with 3D content and a good image with 2d
8. Label the projector macros accordingly

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