(ACB) 'Anaglyphic Contrast Balance' is an embodiment of New Zealand Patent 505513 and U'K' Patent 2366114 + Australian Patent 785021 + Canadian Patent 2,352,272.
Stereo Sight and Sound
 Anaglyphic Contrast Balance is an embodiment of New Zealand Patent 505513 + U'K' Patent GB2366114 + Australian Patent 785021 + Canadian Patent 2,352,272.

WHAT IS 3-D?
STEREOSCOPIC 3-D IS PERCEIVED WHEN THE LEFT AND RIGHT VIEWS AVAILABLE TO EACH EYE FROM THE ORIGINAL SCENE ARE RE-PRESENTED FOR VIEW.

Many on-screen games and images are referred to as 3-D. But they merely display perspective with rotation and motion. This gives a realistic image of a monoscopic single view.
Stereoscopic 3-D requires a left and a right view referred to as a Stereo Pair. The stereo pair may be real, as in photograpy, or fabricated as in a cartoon or drawing. To be effectively viewed, the stereo pair must be presented exclusively to the appropriate eye.

METHODS OF STEREOSCOPIC CHANNELLING THAT ACHIEVE AN EXTINCTION OF THE OPPOSING EYES VIEW TO DISPLAY 3-D IMAGES FROM A TWO DIMENSIONAL SURFACE.
FREE VIEWING typically involves viewing printed images, but they may also be viewed on a monitor.
Parallel Viewing involves aranging the stereo pair with the left image on the left and the right on the right so that an observer diverges their line of sight as if to look through and beyond the images while focused on them. This is easiest when the image width is no larger than the separation of an observers eyes so their lines of sight are not wider than parallel.
Crossed Viewing enables larger stereo pairs to be free viewed. The stereo pair is arranged with the left and right images reversed. An observer converges their line of sight as if to look in front of the images while focused on them. This may result in the stereoscopic image feeling small because your eyes expect to see something small and close when they are converged. Both methods can be achieved with practice.

Try free viewing this stereo pair with your monitor set at 1024x768 or higher.
The left and center images are for parallel viewing.
The center and right images are for crossed viewing.
Parallel view the left and center images. Cross view the center and right images


Rex Julian viewing a stereo pair with a Holmes Stereoscope THE STEREOSCOPE was once so popular in the early 1900's that most families had one. They consisted of a bracket with a pair of viewing lenses. They were used for viewing stereo cards that displayed a photographic stereo pair side by side.
The stereoscope is attributed to Sir Charles Wheatstone in 1838. Simple stereo pair drawings were viewed using mirrors. It was introduced at the begining of photography and the first photographic stereo pair was viewed in 1841. Sir David Brewster then introduced a stereoscope that used lenses in 1849.
Of the many stereoscope models later produced, the Holmes stereoscope of the late 1800's was very popular. Modern stereoscopes are used to view stereo positves or slides such as the View-Master with card reels or the Realist slide viewer for 5 perf' slides that can also be projected.

ANAGLYPHIC 3-D is used with the existing 2-D mediums of print, monitor display and projection. The stereo pair are rendered in opposing color channels and are superimposed for viewing through colored gels. The problem of retinal rivalry in color anaglyphs was solved and patented as (ACB) 3-D. Any color stereo pair may now be instantly processed with the (ACB) 3-D Action Set in Photoshop. See examples in the (ACB) 3-D image gallery.
See also Anaglyphic Viewing.

To the (ACB) 3-D Image Gallery. 3-D Photography by Marc Dawson.


Members of the New Zealand Stereoscopic Society viewing polarised slides with polarised glasses POLARISED 3-D viewing is typically used for 3DTV and still and motion screen projected images. It provides full color perception and can be displayed to a large audiance. During stereo projection, light for the left and right views each pass through polarised filters that are oriented mutually at right angles. The polarised projections are displayed on a metalic or aluminised silver screen to retain the opposing polarised states of the left and right views. The images are then viewed using polarised glasses so that each eye sees only the image projected with a matching polarisation. The opposing view is cancelled out.
The degree of extinction of the opposing eyes view is degraded should a viewer tilt their head as this changes the orientation of the viewing filter in relation to the polarised display.
Two synchronised projectors are required for a strobe free presentation of still or motion picture.
A single projector can be used where the left and right views are displayed sequentially as with Real 3-D in cinemas. The images are projected through an electro-optic polarizing element. When the polarisation is circular, the element alternates between clockwise and anticlockwise states every 1/144 second. The screen receives six cycles of alternate L-R views for each of the 24 frames each second, thus 144 cycles per second. The audience wears passive circularly polarised glasses so that one eye sees only the image projected with matching circular polarisation. This results in a strobed 'view and then no view' for each eye. With circular polarisation, double imaging does not occur should a viewer tilt their head.
Polarised 3DTV Monitor screens
Version 1. A circularly polarised element that is horrizontaly interlaced in opposing directions covers the screen. Each alternate screen scan line is displayed under the opposing polarised strips.
Circular polarised glasses, that don't cause double imaging from head tilt, are used to view the 3-D image from within a fairly narrow vertical zone. The sideways viewing zone is not as restrictive as the vertical viewing zone. The resolution is halved for 3-D viewing. The screen behaves normally for full resolution 2-D viewing.
Version 2. Another polarised monitor method uses an electro-optic polarised element that covers the screen and switches between opposing linear polarised states in sync' with left and right sequentially displayed views. The stereoscopic image is then viewed using polarised filter glasses. This results in a strobed view with each eye receiving half the field display rate.


Carl Watson with a Nu-View video camera attachment, wearing electro-optic shutter glasses. 'There is ghosting and a lot of flicker.' ELECTRO-OPTIC SHUTTER 3-D Light valves such as LCD glasses are typically used for 3DTV monitors or screen projected motion pictures. Left and right views are prepared so that they sequentially alternate when displayed.
The shutter lenses each have a polarised filter and an electro-optic filter. A voltage is alternately applied in response to sinch' pulses between the alternating images. The electro-optic filters become polarised in opposition and prevent light passing and then switch back to a transmisive state. The shutters alternate rapidly between open-clear and shut-dark states in synch' with the images displayed to reveal an alternating sequence of left and right views to each appropriate eye. This results in an observer receiving an alternating strobed 'view and then no view' for each eye.
Video camera attachments can enable alternating left and right views to be captured from a single video camera. An electro-optic mirror alternates between open-clear and shut-mirror states to enable straight ahead views and twice reflected views that are of a wider view angle.

DOLBY 3-D
 is licensed from INFITECH (Interference Filter Technology)
Interference filters divide narrow red, green and blue bandwidths of the color spectrum to each eye providing ghost-free full color 3-D with a digital projector and a regular white screen.
A single projector uses a rotating interference filter wheel installed between the lamp and picture element. The filter divides the color spectrum into six narrow 14nm bandwidths: Two in the red region. Left 629nm, Right 615nm. Two in the green region. Left 532nm, Right 518nm. Two in the blue region. Left 446nm, Right 432nm. The projector outputs a rapid sequence of these color channel bandwidths allocated to the left and right images, refered to as wavelength multiplexing. The viewing glasses are also interference filters and they anaglyphically pass only the narrow red, green and blue color bandwidths allocated for the left and right eyes.
The L-R channel separation exceeds that of polarisation filters. There is no ghosting.
When viewing your suroundings through the glasses, the left view appears slightly reddish and the right view slightly cyan. The opposed filtering causes a slight color difference between left and right channels (retinal rivalry) especially visible in saturated colors. This is not apparent when viewing the superimposed screen image due to an (ACB) selective color adjustment that alters the primary colours to balance the hue contrasts between the left and right red, green and blue bandwidths.
The interference filter wheel can retract for 2-D projection.
Two projectors may be used where each projector allocates the left and right RGB color channels to the (ACB) adjusted left and right images by projecting through interference filters that correspond to the viewing glasses red, green and blue bandwidths.


AUTOSTEREOSCOPIC 3-D or unaided stereo viewing typically involves lenticular channelling used for printed images. Graduations of multiple views, related or unrelated, and also motion sequences, may be displayed as print, via lenticular means.
A monitor can be modified for autosterescopic viewing where interlaced left and right views are covered by a lenticular array which visually channels the left and right views from the monitor. An observer receives an autostereoscopic image if situated within a viewing zone. However, an incorrect viewing angle or distance allows the view intended for the opposing eye.
Another method of autostereoscopic monitor display is Parallax Illumination. An illumination plate behind an LCD screen directionally displays alternate vertical pixel strips that display vertically interlaced left and right images. As with the lenticular system, an observer receives an autostereoscopic image if situated within a viewing zone.

(ACB) 'Anaglyphic Contrast Balance' is an embodiment of New Zealand Patent 505513 and U'K' Patent 2366114 + Australian Patent 785021 + Canada Patent 2,352,272.
Try (ACB) 3-D Viewers.

WHAT IS (ACB) 3-D?

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