3D glasses - glasses for viewing stereoscopic films. The effect of volume is achieved by creating images for different eyes, shot from different points of view.
Binocular vision , which requires two eyes, allows you to see objects in volume. Each eye individually sees a flat (two-dimensional) image . Since there are two eyes and they are located at a certain distance from each other (58–72 mm in adults), images of the same object from two points of view, the so-called parallax , enter the brain. As a result of their processing, a three-dimensional picture is formed. The principle of binocular vision is the basis of 3D films and 3D photographs . A movie or camera with two lenses located at a distance from each other, like the eyes of a person, gives two images that form a stereo pair . If you somehow apply them to different eyes, the brain forms a three-dimensional image. There are different ways of viewing and, accordingly, different types of stereo pairs.
Content
View Formats
One-piece stereo pairs
They are divided into horizontal, vertical, separate.
Horizontal stereo pair (SideBySide)
Frames are arranged horizontally relative to each other. It is divided into parallel and cross. A subspecies of a horizontal stereo pair is an anamorphic stereo pair, in which the clarity of the frame is halved (the frame is compressed) horizontally.
Parallel
The left image is for the left eye, and the right for the right.
Cross
The left image is for the right eye, and the right image is for the left.
Vertical stereo pair (OverUnder)
Two images are located one above the other. Subspecies anamorphic stereo pair. Anamorphic stereo pair - the clarity of the frame is halved (the frame is compressed) vertically.
Separate stereo pair
Used to play video files. Two video sequences are divided into separate streams, namely Separatefiles and Dualstream.
Separatefiles
Video streams are recorded in separate files.
Dualstream
Video streams are united by a common container. One subspecies is Blu-ray 3D / SIFF .
Blu-Ray 3D - a special MVC codec, originally designed to compress stereo pairs, is used to compress video information. The accuracy of angle synchronization is provided not by the player, but by the compression format itself.
Interlaced
Interlaced mixing of both angles in one frame. The image of one angle (for example, the left one) is recorded in even scan lines, and in the odd lines of another (for example the right one). In this case, the vertical resolution of each angle is halved.
Chess
Mixing both angles in a checkerboard pattern. [one]
Anaglyph
Color coding of the image, designed for the left and right eye with the help of filters.
Viewing Methods
1. Active 3d glasses (with active shutter)
Transfer the image to each eye in turn. Active shutter 3d glasses use liquid crystals as lenses, which are capable of alternately closing and opening the left and right eyes under the influence of a control signal at high speed. This allows you to get a 3d effect by transmitting a separate image to each eye. Active 3d glasses are synchronized with a TV or monitor, which is usually realized through the infrared port , less often - mixing the signal with the video stream (HQFS DVD standard).
Used to view photos, films and computer games, along with auxiliary equipment for viewing on 3d-TVs and 3d-monitors for all viewing formats, except anaglyph. Also used to watch 3D movies in cinemas with XpanD technology.
2. Passive 3d glasses
Transfer the image to each eye at the same time.
2.1 Polarized 3D Glasses
The left and right glass transmits the image only with its polarization. They are divided into subspecies using linear and circular polarization .
a) linear polarized 3d glasses
Used to view photos and movies, along with auxiliary equipment for viewing on 3d-TVs and 3d-monitors for all viewing formats, except anaglyph. Also used to watch movies in cinemas with IMAX 3D technology.
b) circular polarized 3d glasses
Used to view photos and movies, along with auxiliary equipment for viewing on 3d-TVs and 3d-monitors for all viewing formats, except anaglyph. Also used to watch movies in cinemas with RealD 3D technology.
2.2 Anaglyph glasses
The method uses the separation of the image into two colors, for example red and blue, and overlays them next to a small offset. At the same time, the viewer, using anaglyph 3d glasses with filters from lenses of the same blue and red color, gets an image for each eye. Thanks to this, a stereo effect appears. Used only for viewing photographs and films in anaglyphic format.
The modern subspecies of anaglyph glasses uses several interference filters (sometimes called “super-anaglyph”), distorting colors to a lesser extent than when using single-color filters. Such glasses are used for viewing in cinemas using Dolby 3D Digital Cinema technology.
2.3 Mirrored 3d glasses
To obtain a 3D image, the technology of mirror information of angles, carried out by adjusting the tilt of the mirror glasses. Two pairs of mirrors (for the left and right eye) allow you to bring together two images located on the screen of one (any model and technology) monitor. Used only for viewing photographs and films in the format of a horizontal parallel stereo pair.
Criticism
Watching 3D movies both in the cinema and on the 3D TV screen in 3D glasses is difficult for people with visual impairments and forced to wear glasses with diopters , since 3D glasses can not always be worn on or under the diopter, while In any case, an additional load is created on the eyesight due to glare arising between the lenses and on the bridge of the nose due to the large weight of the structure from two pairs of glasses.
It was noted that 3D glasses distract from watching the movie, interfering with the viewer. Here is what the famous director said about this:
I always liked 3D. But, unfortunately, I have seen very few films that really need it. For the most part, after watching, you remember the damn glasses on the nose, and not what they give. Therefore, I often ignore three-dimensional versions and prefer to watch the usual ones.
- Conversation of Oleg Sulkin with Quentin Tarantino // Results
Notes
Literature
- Lenny Lipton Foundation of the stereoscopic sinema a study in depth. - to be published by Van Nostrand Reinhold 1982
- Herbert C. McKay Three-Dimensional Fotography Principles of Stereoscopy - 1953 American Photographic Publishing Company