Image generation
During image generation , geometric information is converted into a visualizable image.
A distinction must be made here as to whether
- a real object is recorded with an image recording device for the purpose of obtaining information, for which, for example, imaging processes can be used,
- a digital image can be generated virtually with the aid of computer graphics , or
- an existing information with an image reproduction device in an image shown is what often raster graphics are used.
Some devices have both image capture and playback functions. The combination of the generation of digital images of real objects with the image reproduction in real time is referred to as virtual reality . If virtual image content is also added, it is referred to as augmented reality .
Furthermore, a distinction can be made between the following image properties when generating images:
- Still images and moving images .
- Monochrome and polychrome images
- Two-dimensional and three-dimensional images
Image capture devices
Many image capture devices use optical imaging to generate images . Cameras and X-ray devices generate real images , whereas microscopes or telescopes can also generate virtual images that are not registered directly but are viewed with the naked eye .
In the stereoscopy and spatial information is recorded. Omnidirectional cameras record the entire solid angle with a single shot .
Dark objects can be brightened by using light sources such as flashlights or spotlights .
Image storage
If real images are not to be reproduced immediately, they can be captured with photographic film or an image sensor . If the film has been developed or the signals of the image sensor have been stored non-volatilely after digitization and image processing in a specified color space , these stored image data can be reproduced at a later point in time, for example with an image viewer . Digital data can be copied as often as required without loss of information . Digitally stored images can be edited with computers .
In digital technology , images can only be stored briefly in a volatile data memory and displayed in real time via live view .
Image display devices
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Typical image display devices are screens , printers or projectors .
Here, the light from a light source can be modulated spatially and temporally for the image reproduction, for example with a grating light valve , in a cathode ray tube , a laser scanner or a liquid crystal display . It is also possible to use several light sources at the same time, which are arranged like a grid and can be controlled individually, as for example in plasma screens or OLED screens .
Printers require a light source for viewing after imaging. Standard light can be used for true color reproduction .
In older screens, a modulated and scanned electron beam is used to create a real image on a layer with a luminescent phosphor . When using differently colored phosphors, the image can also be generated in a color picture tube .
Some image reproduction devices such as slide viewers and electronic viewfinders require imagers whose real images are converted into virtual images with the aid of an eyepiece .
A real picture is generally displayed on a screen . If the imager itself does not generate any light for such an optical image, but requires an additional light source with a corresponding illumination beam path, an interwoven beam path is usually used.
Various imaging elements can be used for imaging devices in digital projectors or electronic viewfinders, such as a micromirror actuator , an eidophor , a liquid crystal display, a display with LCoS technology or an OLED microdisplay.
literature
- DIN EN 61966, parts 1 to 12: Multimedia systems and devices - color measurement and color management
- ISO 12651 Part 1, January 2012, Electronic document management - Dictionary - Electronic image generation / Electronic document management. Vocabulary. Electronic document imaging
- ISO 12653 Part 3, April 2014, Electronic imaging - Test template for scanning office documents / Electronic imaging - Test target for scanning of office documents
- Bunke J. et al. (2003): Physical-technical principles of image generation , in: Schmidt T. (editor): Handbuch diagnostic radiology. Manual diagnostic radiology , Springer, Berlin, Heidelberg, ISBN 978-3-642-62553-4 (printed) / ISBN 978-3-642-55825-2 (online)
Web links
Individual evidence
- ↑ OLED microdisplay , Design & Electronics - Optoelectronics from April 4, 2017, accessed on July 4, 2018
- ↑ OLED microdisplay: When plastic suddenly lights up , Federal Ministry of Education and Research , accessed on July 4, 2018