Topographical effects

1
Topographical effects
Different tilt angles were used to demonstrate
the effects on the perception of
topography. Tilt compensation was also used as a
tool to correct for the vertical image
distortion.
Penny 15x 45 degree tilt w/ corresponding gray
level histogram
2
Penny 15x 0 degree tilt, w/ corresponding gray
level histogram (less contrast, histogram skewed)
3
Penny 15x 70 degree tilt, more topographical
contrast
Penny 15x 45 degree tilt
Penny 15x 70 degree tilt w/ 70 degree tilt comp.
Essentially the image is stretched notice the
aperture now appears oblong instead of round.
Penny 15x 45 degree tilt w/ 45 degree tilt comp.
4
Regular image
Same image but stretched in Y (same thing as
tilt comp)
With Tilt Comp
5
A work of caution is needed for the
interpretation of 3D effects. The location of
light and shadow can deceive the eye. A good
example of this can be seen in the book on pages
212-213. The difference between bottom
illumination (left) and natural illumination
from above (left) can be significant.
Same deal but this time at 70 degree tilt
6
We also observed how very high tilt can cause the
image to lose focus at the top and bottom of the
image
7
In addition to tilt effects, Stereo pairs were
also collected to demonstrate 3D imaging (the
tilt axis is horizontal so turn the pictures 90
degrees in the stereo viewer)