Jonathan Gin Joseph Leong Psych 221 March 11, 2003

1. Jonathan Gin Joseph Leong Psych 221 March 11, 2003

2. Motivation:WHAT is that???

3. Advances of Stereography 1832 1979 1959 • 1832 – Wheatstone creates the first stereoscopic viewer • 1959 – Julesz creates the random dot stereogram • 1979 – Tyler designs the first single image random dot stereogram

4. What is Stereography? • The word stereo originates from the Greek meaning spatial (3D) • Our eyes view the world from different perspectives allowing the creation of • 3-D images in 2-D planes

5. Importance of Stereography • Entertainment (VR, 3-D displays) • Medical Imaging • Terrain Mapping

7. Step 1

8. Step 2

11. AutoStereograms • Throw out those viewing glasses! • Autostereograms can be categorized as Random Dot Stereograms or Bitmap Patterned Stereograms: Autostereograms

12. Algorithm to Making Random Dot Stereogram • Start with a depth map. • Taking each horizontal line at a time, impose the constraints of the pixels. • Scan the horizontal line, this time filling in the unassigned pixel values with random numbers. • Do this for all horizontal lines.

14. Depth Map • You can load in a depth map………. • Or Create your own!

15. Some Interesting Considerations… Removal of Obscured Points

16. A distortion called “Echoes”…. • Accidental occurance that two sets of points share a common point = Overlapped Dots

17. An Accurate Separation Distance Formula

18. Bitmap Pattern Stereography • easier to see than random dot stereograms • implementation very similar to random dot case

19. How to View Stereograms? • Stare through the picture, and concentrate •  These didn’t work for us….. 2. Look at your own reflections and stare!!!

20. TA DA!!! Random Dot Bitmap Pattern