Interlacing (graphics)
As interlace or interlacing (English pronunciation [ ˌɪntəˈleɪsɪŋ ]) is a storage method for raster graphics , which enables the quick creation of an overview or preview image (in full image size) when loading a graphic .
Technical details
The interlace method was originally achieved by saving only every eighth image line at the beginning of the automatically processed graphic file and then the missing lines. This is similar to the interlacing method for displaying television images, which is also known as interlacing in English . With more recent methods (see Adam7 ) a two-dimensional selection of the image points is saved.
When loading an image slowly, for example via a connection with a low data transfer rate , the viewer has the impression that the image becomes ever sharper and more detailed as it is being created. This method of saving is advantageous if the loading time of an image is long. However, this also increases the size of the graphic file.
The graphic formats GIF , PNG , Kodak Photo CD, and Progressive JPEG support interlacing.
It should be noted that this process is called progressive in JPEG , although in English the two terms progressive (for the full-screen process ) and interlaced (for the interlaced process ) are opposites when referring to the process of image construction in television technology.
Web links
- Stephan T. Lavavej: Introduction to PNG. In: nuwen.net. (English, including comparison of interlacing in GIF and PNG).
- Interlaced video. In: ScienceDirect . (English, overview of ScienceDirect literature on interlaced video with direct access to the relevant chapters / articles (as a restricted preview)).