Image transformation

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As image conversion (Engl. Image conversion ) is defined as

  1. the automated conversion of an optical image into an electrical signal;
  2. the digitization of an analog image ( A / D conversion );
  3. the analog reproduction of a digital image ( D / A conversion ).

Overview

All photographic processes carry out an image transformation, ie they change the subject according to defined rules; Conventional photography, for example, reduces the spatiality and converts a three-dimensional image into a two-dimensional one, a fisheye lens distorts the perspective image in a barrel-shaped manner compared to human viewing habits.

The first image conversions from static images were implemented with image telegraphy and later in image telephony . The first image changes from moving images came from Paul Nipkow's Nipkow disk . With this optoelectronic image conversion, optical images are broken down into points and lines, transmitted as a signal and reassembled to form an optical image.

digitalization

The conversion of an analog into a digital image includes discretization and quantization , whereby the parameters image resolution , color space and color depth are defined. The digitization can be done, for example, by a scanner or a frame grabber .

When converting the file format of digital image files ( conversion ), on the other hand, no image conversion takes place, since the "aggregate state" of the image is not changed.

Imaging procedures

Particularly extensive image transformations are carried out in the imaging process ; These are calculated images , ie facts are visualized that are otherwise inaccessible to the unarmed human eye.

Problems

A typical problem when digitizing image data is the occurrence of moiré effects .

See also

literature

  • Rolf-Jürgen Ahlers (Ed.): The handbook of image processing. Methods - Programs - Applications . Expert-Verlag 2000. ISBN 3-8169-0675-3

Web links