What is Stereo Window?!
(By Shahrokh Dabiri)
This is a common question that almost all 3D newcomers are facing.
If you’d like to create a relaxing 3D picture that everybody would enjoy without eyes strain you should learn how to adjust the stereo window position and for each of your 3D images.
Stereo window is not a hard subject to understand, it's just your monitor surface, it's your picture frame, it's your paper surface. Now let me explain it in details by showing you a few pictures that I have made - just put on your Anaglyph glasses right now;
Look at the image above carefully. it represents the CORRECT STEREO WINDOW POSITION because all the picture elements are located behind the picture frame/monitor surface. You see the depth that begins from the closest foreground (shovel tip) and ends in the background (the tree). Here,
the layers of depth are correctly located behind the stereo window/picture frame/monitor surface. Although the shovel tip is
touching the stereo window, it doesn't come out of it so that the shovel is still behind the Window!
Most of 3D pictures are presented in this way because they are very easy to view. I mean you see the depth completely
behind the Stereo Window and your eyes can easily fuse the two pictures to get the right 3D effect.
Below is my second 3D example that conforms with the above rule.
In this sample the boy is standing far behind the Window but his ball is close to the Stereo window. Nothing pops up from the Stereo window or nothing pops up toward your face in this case. All the picture elements show a
CORRECT STEREO WINDOW position.
-------------------------------------------------------------
Now I'm going to slide my Stereo chips (Left/Right pictures) over each other to see what would happen with my stereo window position. I have shifted my chips so that the boy’s body overlaps.
As you see on the sample above the boy is standing AT the stereo window but his shovel is
coming out through the window or his shovel pops up toward you. The shovel is located in front of the stereo window. The depth path begins from his shovel tip (located in front of the window) to the tree in background (located behind the window) and this is CORRECT STEREO WINDOW position too.
Regarding the stereo window rules a picture element may correctly come out through the window if it’s not cropped (clipped) by the stereo window border or the picture frame. This
Through The Window effect (TTW effect) is so pleasing to many and may add excitement to your 3D pictures.
Here below you find another sample for a correct through the window effect.
This a CORRECT STEREO WINDOW position too. The boy is standing right behind the window. his right hand is
touching the window and his ball comes out through the window (TTW effect). There is no
Window violation (WV) on this image.
--------------------------------------------------------
Now I'm going to show you how those pleasing 3D effects can be ruined by a wrong cropping action or a false window positioning.
This sample shows a INCORRECT STEREO WINDOW position. This picture has a strong Window Violation and bothers the viewer eyes because the path of depth is not natural on this image. The shovel tip has been mounted to show a Through the window effect but its tip has been cut by the Stereo window/picture frame. There is no logic on this image depth path. How this TTW shovel tip could be cropped by the picture frame that is located behind it !!! If it’s in front of the window how come the frame obscures it?
The picture above shows the Window violation or the picture WINDOW IS NOT CORRECT. On this image, the ball is supposed to come out through the window but it has been cropped out by the picture window/frame. This image bothers the eyes because "how a ball may pop up toward you while it has been
covered by the picture frame that is located behind its position" !!! Eyes don’t like those paradoxes.
---------------------------------------------------------------------
Through the window effect is so pleasing if you mount your picture wisely or understand its logical position. False TTW effect violates the stereo window rules. It is unpleasant or bothers your eyes/brain.
In a few of my examples the ball and the shovel correctly come out through the window. There are many situations when you can use TTW effect with pleasing results, such as a tree branch, a pointing hand toward your camera, an elephant trunk extended directly to your camera, and so on.
------------------------------------------------------------------------
I have tried to point out to some common elements regarding the Stereo window rules.
------------------------------------------------------------------------
Notes:
1. Adding a frame to your digital image helps you find the proper position of your picture’s stereo window. I strongly recommend that. You can remove the frame after you finished the window adjustment if you want to. Most of the 3D softwares such as Stereo Photo Maker "SPM", Anabuilder or Gugsoft let you create neat beautiful frames around your stereo chips - your left/right pictures.
2. When you are working with a digital pair the above mentioned software helps you slide or move your chips to left or right until you find the proper window position. Adjust the window position working with Anaglyph format because it reveals the best all possible flaws. Later, when you finish the window positioning, you can save your adjusted stereo in any desired format such as side by side format (parallel, P) or cross eyes format (X).
3. If you are dealing with stereo Prints or Slides then you should crop the outer borders out (obviously same amount from each chip) until you get the proper window position. In the digital format a good 3D software does that cropping job for you with just a few clicks.
-------------------------------------------------------------------------
If you need more help on understanding the Stereo Window subject just send me an email;
----------------------------------------------------------------------
Sincerely yours,
Shahrokh Dabiri. (May 2007)