Field
The term field is used in video and television technology as well as in stereoscopy . It is intended to symbolize the imperfection of a single field. The desired visible images result only in pairs of fields in common.
Half frame in television and video technology
-field_(Interlace).gif)
In order to convey the impression of fluid motion sequences with classic (not high-resolution) television signals without requiring an excessively high bandwidth for transmission , the signal is divided into 25 or approx. 30 images / second, depending on the national television standard, which in turn is divided into two fields (odd / even) can be divided. These fields are also called fields .
Depending on the video source (uncompressed or MPG-encoded) either
1. the first field is formed from the even (even or bottom field), the second field from the odd lines (odd or top field) (uncompressed)
or
2. the first field from the odd (odd or top field), the second field from the even lines (even or bottom field) formed (MPG)
In this graphic, a full image is made up of two fields, the first field being shown in blue and the second in yellow.
This technique is still used in many video and television formats.
When playing films with field technology, visible lines appear on a screen without an additional filter. These do not appear on a television set because the lines merge into one another.
This procedure is called interlace method (engl. Interlace ).
Stereoscopic field
Stereoscopic (spatial) vision is only possible with two eyes. In order to be able to create a spatial impression with a stereoscopic photography, an image (half image) recorded at eye distance must be available for each eye. These two images must be presented separately to one eye each so that the spatial impression can arise. Various methods are used to separate them, such as 3D glasses or lens grids .