1. 3D principles
1.2 The difference between Active Stereo & Passive Stereo output
About
The Barco P ulse based projectors have an implemented functionality for Active 3D output, which is the s tandard mode for the Pulse
platform.
In add ition, the P ulse platform also hav e the p ossibility for rendering pass ive 3D. Th is requires a special v ersion of the p rojector
which can be ordered on a separate ar ticle num ber. This version contains ex tra hardware in the optics path.
What is Passive Stereo output?
Passive S tereoscopic 3D (also known as “Pa ssive Stereo”) is the traditional, standard method of creat
ing the illusion of depth in an
image, by using pas sive goggles.
There are several sub methods, such a s:
• Different color spec trum on each channel (eye), recognized by goggles with different colored glas ses.
• Polarizing m ethod with different polarization on each channel (eye) using passive goggles with polar
ized lenses. The Barc o
passive stereo output uses the polarization m ethod.
In order to preserve the polarization, a silver screen must be used.
On m ost passive displays ev ery other row of pixels are polarized for one eye o r the other. This method is also known as interlacing.
Passive output also requires e xternal equipment in t he form of a ac tive p olarization filter moun ted in front of the lens. This equipment
is supplied from a 3
rd
part vendor.
The v iewer wears passive g lasses which contain a pa ir of o pposite polarizing filters. As each filter only passes light which is sim ilarly
polarized and blocks the oppos ite polarized light, each eye only sees one o f the images, and the effect is achieved.
Image 1-2
What is Active Stereo output?
Field sequential 3D (also k nown as active 3D or A
ctive S tereo) is a technique of displaying stereoscopic 3D ima ges, which is the
standard mode for the Pulse platform.
The principle of operation is that the image intended for the left eye is presented while blocking the right eye’s view, then presenting
the right-eye image while block ing the left eye, and repeating this so rapidly that the interruptions do not interfere with the perce ived
fusion of the two im ages into a single 3D image.
This system se tup uses liquid crystal shutter glasses ( also known as active shutter glasses). Each eye’s glass c onta ins a liquid
crystal layer which has the property of becom ing opaque when voltage is applied, being otherwise transparent. T he glasses are
controlled by a timing signal that allows the glasses to alternately block one eye, and then the other, in synchronization with the
refresh rate of the screen. The timing sync hronization to the video equipment may be achiev ed via a wired s ignal or via wireless
communication, this by using eith er an infrared or radio frequency (e.g. Bluetooth, DLP link) transmitter.
There are several types of 3D glasses available from 3
rd
part vendors.
If a 3D emitter is used that radiates IR beam s, the IR beams may interfere with the IR communica tion b etween
projector and the remote control unit. If such interference occurs, connect the RCU to the projector u sing the
remote cable. It is also advised to turn the IR receivers on the projector off to avoid the 3D emitter interference.
To turn off the IR receivers, refer to the User g uide for the projector concerned.
The options in the projector software allow you to fine-tune the 3D settings accordingly to the specifications of the 3D emitter.
4
601–0469 3D FUNCTIONALITY PULSE PLATFORM 27/02/2018