Alternate-frame sequencing
Encyclopedia
Alternate-frame sequencing (sometimes called Alternate Image, or AI) is a method of showing 3-D film
that is used in some venues. It is also used on PC systems to render 3-D games into true 3-D.
is filmed with two camera
s like most other 3-D films. Then the images are placed into a single strip of film
in alternating order. In other words, there is the first left-eye image, then the corresponding right-eye image, then the next left-eye image, followed by the corresponding right-eye image and so on.
The film is then run at 48 frames-per-second instead of the traditional 24 frames-per-second. The audience wears very specialized LCD shutter glasses
that have lenses that can open and close in rapid succession. The glasses also contain special radio receivers. The projection system has a transmitter that tells the glasses which eye to have open. The glasses switch eyes as the different frames come on the screen.
and Nintendo Famicom
. Special software or hardware is used generate two channels of images, offset from each other to create the stereoscopic effect. High frame rates (typically ~100fps) are required to produce seamless graphics, as the perceived frame rate will be half the actual rate (each eye sees only half the total number of frames). Again, LCD shutter glasses synchronised with the graphics card complete the effect. Aside from consoles, alternating frames to render 3-D images was used in some arcade games, most notably Sega's Sub-Roc 3D in 1982, Namco's Thunder Ceptor II in 1986, and Taito's 1987 racer, Continental Circus
.
3-D film
A 3-D film or S3D film is a motion picture that enhances the illusion of depth perception...
that is used in some venues. It is also used on PC systems to render 3-D games into true 3-D.
Applications in film
The movieFilm
A film, also called a movie or motion picture, is a series of still or moving images. It is produced by recording photographic images with cameras, or by creating images using animation techniques or visual effects...
is filmed with two camera
Camera
A camera is a device that records and stores images. These images may be still photographs or moving images such as videos or movies. The term camera comes from the camera obscura , an early mechanism for projecting images...
s like most other 3-D films. Then the images are placed into a single strip of film
Film
A film, also called a movie or motion picture, is a series of still or moving images. It is produced by recording photographic images with cameras, or by creating images using animation techniques or visual effects...
in alternating order. In other words, there is the first left-eye image, then the corresponding right-eye image, then the next left-eye image, followed by the corresponding right-eye image and so on.
The film is then run at 48 frames-per-second instead of the traditional 24 frames-per-second. The audience wears very specialized LCD shutter glasses
LCD shutter glasses
Liquid crystal shutter glasses are glasses used in conjunction with a display screen to create the illusion of a three dimensional image, an example of stereoscopy. Each eye's glass contains a liquid crystal layer which has the property of becoming dark when voltage is applied, being otherwise...
that have lenses that can open and close in rapid succession. The glasses also contain special radio receivers. The projection system has a transmitter that tells the glasses which eye to have open. The glasses switch eyes as the different frames come on the screen.
Applications in gaming
The same method of alternating frames can be used to render modern 3-D games into true 3-D, although a similar method involving alternate fields has been used to give a 3D illusion on consoles as old as the Sega Master SystemSega Master System
The is a third-generation video game console that was manufactured and released by Sega in 1985 in Japan , 1986 in North America and 1987 in Europe....
and Nintendo Famicom
Nintendo Entertainment System
The Nintendo Entertainment System is an 8-bit video game console that was released by Nintendo in North America during 1985, in Europe during 1986 and Australia in 1987...
. Special software or hardware is used generate two channels of images, offset from each other to create the stereoscopic effect. High frame rates (typically ~100fps) are required to produce seamless graphics, as the perceived frame rate will be half the actual rate (each eye sees only half the total number of frames). Again, LCD shutter glasses synchronised with the graphics card complete the effect. Aside from consoles, alternating frames to render 3-D images was used in some arcade games, most notably Sega's Sub-Roc 3D in 1982, Namco's Thunder Ceptor II in 1986, and Taito's 1987 racer, Continental Circus
Continental Circus
Continental Circus is an arcade racing game created and manufactured by Taito in 1987. It was then republished in 1989 along with a home version of the game, which was available on various platforms including the Amstrad CPC, Atari ST, Amiga, Commodore 64, MSX and ZX Spectrum.The arcade version of...
.