Projector Alignment for the One Computer Configuration with the Wii Remote

Overview and Strategy

Regardless of what version of Science On a Sphere you have, the goal of projector alignment is the same: Align the projectors so that there appears to be one continuous image on the sphere, rather than four images. Here are the basic steps for aligning the sphere:

Gather projector and room parameters for all of the important distances (and add them to the sos_stream_control.config file)
Do a factory reset on your alignment parameters (very important for new projectors!).
- Either remove the alignment.dat files or bring up the alignment interface and do a "factory reset" and then save it.
Start SOS, bind/connect the Wii (if applicable), and bring up the alignment interface.
Physically position the projectors using the red ball.
- The goal here is to use the projector's zoom such that the rectangular light background of the projector illuminates the sphere completely from top to bottom with a little overshoot at the top and bottom. If the projected light from the sphere is zoomed out too large, you'll end up wasting pixels and light output.
- Center the projected red sphere on the physical sphere as close as possible. Physically adjust the projector mounts to center the image.
- With the alignment interface up, turn on the grid and make sure the horizontal line representing the equator is level (i.e. parallel with the floor).
- Lock down the projector mounting screws once this is done.
Use the alignment software to complete the process. Proceed to the section about aligning the sphere based on your setup.

There are three versions of directions, one for the five computer set up with the ATI remote, one for the five computer set up with the Wii remote, and one for the one computer setup with the Wii remote. Please make sure that you follow the right directions for you.

Step-by-Step Directions

Logged in as the user 'sos', open the SOS Stream GUI and make sure that the Wii remote is connected. Once te remote is connected, open the alignment software using the "Alignment" icon on the desktop.

This will launch a web browser with an interface for the Alignment software. Click "Alignment".

Another window will open that has the Wii layout for alignment use and the launcher for alignment. Click "Start Alignment".

After clicking start alignment, select which dataset to use first. It is recommended to use "Red grid (coarse)" first. Clicking on it will load the image on the sphere.

Once the red grid is loaded on the sphere, use the Wii remote to align the sphere. There are two main modes for aligning the sphere, "Projector Alignment" and "Vertex Tweaking." If you are aligning the sphere for the very first time, or if it is really out of alignment, then start with the Projector Alignment. If you are just tweaking the alignment, then start with Vertex Tweaking.

Projector Alignment

The first step in Projector Alignment uses the "Red Ball." To turn the Red Ball on or off, press "1" on the Wii remote. When you are using the red ball, you only need one projector on at a time. You can toggle the projectors on and off using the Wii remote. The "+" and "-" buttons allow you to select the projector that you are working with. The four blue lights at the bottom of the remote indicate which projector is selected. To turn the image on a projector on or off, make sure it's the selected projector then press the "A" button. The goal when using the red ball is to have the red cover the surface of the sphere and not overshoot the sphere on any side. You also don't what to see any cyan on the sphere. You can adjust the position and size of the red ball by using the buttons on the remote. The image can be adjusted in three different modes: translation, scale, and rotation. To use translation mode use the joystick on the nunchuk. In translation mode, the joystick can be used to move the image left, right, up and down. To use the scale mode, hold the "Z" button while using the joystick. In scale mode, up on the joystick makes the image taller, down on the joystick makes the image squatter, right on the joystick makes the image wider, and left on the joystick makes the image thinner. To use the rotation mode, hold the "C" button while using the joystick. In rotation mode, the joystick can be used to rotate the image as necessary. Once you are satisfied with the red ball alignment it is probably a good idea to save the alignment by holding the Home button on the remote (the little button between the "-" and "+" buttons. A notification should show up on the sphere to confirm the save. All of the changes that are made to the projectors are only saved when the home button is held down. If changes are made that you don't want to keep, you can revert back to the last time you saved by holding the "2" button.

The next step in Projector Alignment utilizes the Red Grid. Make sure that all of the projector images are on and turn off the red ball image. There should be a grid that cover the whole sphere. Once the red grid is on the sphere, the goal is to have the grid line up between the projectors so that it looks like one seamless image. You can again turn the projectors on and off by pressing "A" to see which projectors are causing overlap. You will want all of the projectors on most of the time when working with the Red Grid. Adjust the image just as you did with the Red Ball, working to create a seamless image. You don't have to get the lines absolutely perfect in Projector Alignment because you will do the fine tuning with Vertex Tweaking.

Vertex Tweaking

Once the image is fairly close to being seamless, turn on Vertex Tweaking by pressing "B" on the Wii remote. The selected projector should display a grid with the numbers 1-9 on the sphere. Use the D-pad on the remote to move around the grid. When you have a number selected, you can use the joystick to stretch the image up, down, left and right. The image will only stretch near the selected number, so if a whole side needs to move left, then you need to stretch it at the top, middle and bottom. It is sometimes confusing as to which line is being projected from which projector, so it is helpful to toggle the adjacent projectors on and off to differentiate between the lines. Also, if two lines are separated that shouldn't be, it is good to move each of them half way and have them meet in the middle rather than moving one line all the way to the other. Once all of the lines meet in the grid, make sure to save the alignment. To perfect your alignment, you can load "Red Grid (fine)" from the menu, which has higher resolution and thinner lines. You will probably have to make some additional adjustments when you put the high resolution grid up. Follow the same steps as when "Red Grid (coarse)" was used.

When you are satisfied with your alignment, save the alignment for a final time and then press "Stop Alignment" to return the remote to Play Mode.

Notes

If you physically move your projectors or if the alignment is really off, you can revert to the factory defaults by holding button 2 on the remote. If you hold button 2 for two seconds, it will revert to the last saved version. If you continue to hold button 2 for six seconds, it will then revert to the factory defaults. You will lose all of your current settings if you press reset to factory defaults, so make sure you are careful to only press it when you mean to.