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.
"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
|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.
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.
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.