Posters illustrating visual phenomena:
from Da Vinci Days, 2000

June 22, 2000 The two "Human Vision" posters on the left illustrate the importance of edges to our vision.  Up close, the portrait at the top is just a bunch of tally marks. 

(Lower poster) The eye is almost unrecognizable up close: it's a half-tone of huge dots.  The gargoyle (on the left) is composed entirely of little icons: close up, the gargoyle is completely unrecognizable. The dalmatian is the famous photo that illustrates what happens when edges are taken away.

The three posters on the right:
The two eyes are from our Web site, "The three Cyclops of ancient mythology...They are watching you.  Do you see them?"

"See like a giant!" illustrates how climbers can find routes using large-base stereoscopic pairs of photos.  Arches National Park's Old Maid's Bloomers (sometimes called "Delicate Arch") illustrates the distinction between eye-crossing and eye-spreading for unaided stereoscopic viewing. SEE MORE         . . . & MORE

The crystal model photos illustrate how we make something look very big by taking a stereoscopic pair with a very small inter-camera distance.  ("See like a gnat.")

"If you don't take your stereoscopic pairs of photos at the same distance as that between your eyes you will exaggerate or flatten the depth when you view the pictures in a stereoscope." FALSE

What happens when edges are taken away?

This is an image of a familiar object.  However, because we recognize shapes by their edges and the edges have been removed from this image, we don't see the object.  The edge is the boundary between the smooth dots and the irregular dots.  By drawing that boundary in, we can see the object.  At Da Vinci Days several of these drawings were laminated in plastic so that outlines can be drawn and erased using erasible felt pens.  Here on the Web, you might draw the outlines on your glass-faced CRT's with erasable felt pens.  (??...We think that you shouldn't draw on plastic flat screens, such as laptop screens, etc.  Place a sheet of Saran Wap over your screen and draw on that?)


Figures made of dots can be masked by other patterns of dots.

But motion of the dot patterns can re-reveal what got hidden
Click on the cats to see much more.

This phenomenon is easily demonstrated at home or school
by drawing dots on transparent sheets.

A motion picture taken from a low-flying aircraft reveals the depth
of objects on the ground because of the aircraft's motion.

Stereoscopic patterns and patterns in motion
are processed in the same region of the brain.

The depth we perceive from watching a motion picture taken from an aircraft,
and the depth we perceive by taking two frames from that motion picture
and viewing them stereoscopically, "feel" remarkably similar.