Zickler used
apertures of different chromaticity to take pictures. Since aperture size
determines the depth of focus, an image taken with a camera with different
apertures will have different depths of focus for different color. This
information allows the researchers to estimate the depth of different objects
in the image.
Bank investigated
different 3D display technologies. He focused on depth distortion. Left-right
lateral movement on a stereo display appears forward and backward movement in
depth. It may be an artifact caused by the current time-sequential display
technique. He used a rotating wheel stimuli (disks of different disparity
rotating about the fixation point) to measure the nulling depth and estimate
the distortion.
Read showed that
much disparity information n the retina is lost when disparity is encoded in
V1. She used gratings modulated in depth (cf. Kontsevich & Tyler). V1 has
on-off regions for luminance but same-disparity tuning for the whole receptive
field. Therefore, some areas must integrate V1 cells to see gratings modulated
in depth. The cell response for sinewave grating depends on the depth
modulation, but not square wave. It is because that larger disparities is
encoded by larger receptive fields. To design video codec, it is better to have
high resolution monocular images with low resolution depth maps. The depth
percept has even less information than V1. In addition, it is easier to detect
horizontal grating than vertical grating at lower spatial frequencies. She also measured the reverse correlation
threshold for joined disparity and motion grating. The reverse correlation threshold allows her
o estimate the receptive size for disparity and motion. The RF tuned t
different combinations of motion and disparity. It is unlikely to be MT
neurons. So, Information is read out from V1, but it is not clear who read it.
Tsirlin from Wilcox
's lab talked about cross talk on perceived depth in 3D displays.
Crosstalk=(leakage/signal)*100%.
Crosstalk reduce image quality, quality of depth and induce discomfort.
She asked observer to estimate the depth of two bars with and without cross
talk. Increase in cross talk reduced perceived depth. Significant reduction
started at 4-8% cross talk.
Kazimi from 3D film
innovation consortium taled about Hazardous stereography. UK constraint disparity to be 4% positive (object in front of the
background) and 2% negative as safe zone. Depth
setting changes with display size.
Rudd. Lightness
contrast with two contexts. The target disk is surrounded by an immediate
surround and then on a large background. The radius of the surround has an
effect on the perceived lightness of the target. The matched target luminance peaks at certain
physical luminance, suggesting a contrast gain control mechanism.
