Eye-tracking autostereoscopic systems require fast response times of less than 100 ms and must track head and eye movements.

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Ulrich Leiner, researcher from the Fraunhofer Heinrich-Hertz Institute talked about evaluating motion and binocular parallax as depth cues in autostereo displays.

3-D displays have a number of applicable technologies for showing images. Autostereo displays operate by providing two or more views to a single viewer. The problem is that these views only show a reasonable 3-D image in a few angular dimensions, the sweet spot(s) are limited. To address this problem, his research uses a display-mounted camera to view the user’s eyes and steer the visual fields to the eye locations.

This image feedback system requires fast response times of less than 100 ms and must track head and eye movements. To be useful, the system needs to be robust and not be affected by skin color, eye color, hair cuts and changing levels of illumination. To move the images on the display, there are three possible –mechanisms. They could control the focused backlight, shift and scale the pixels, or move or switch the beam splitter.

They found that it is hard to shift the pixels at the subfield levels and moving a focused backlight didn’t produce a comfortable image. As a result, they are using a mechanical structure to move the vertical lenticular lenses across the x-axis to match the head and eye movements. A feedback loop including the viewer combines the binocular images and horizontal displacement to increase the 3-D effects in the image.

In testing the apparatus, they found that motion parallax is much less effective as a depth cue than the binocular cues. By combining the two, viewers experienced a 20-30 percent increase in perceived depth over either set of cues separately. The resulting images are close to holographic images. The likely applications for this enhanced viewing technology are those that need critical depth information. Some of these applications include medical (especially robotic-assisted surgeries and tele-medicine) and gaming.

See original post here: http://mandetech.com/2011/02/02/motion-and-binocular-depth-cues/