A focus-plus-context screen is a specialized type of
display device
A display device is an output device for presentation of information in visual or tactile form (the latter used for example in tactile electronic displays for blind people). When the input information that is supplied has an electrical signal the ...
that consists of one or more high-resolution "focus" displays embedded into a larger low-resolution "context" display. Image content is displayed across all display regions, such that the scaling of the image is preserved, while its resolution varies across the display regions.
The original focus-plus-context screen prototype consisted of an 18"/45 cm LCD screen embedded in a 5'/150 cm
front-projected screen. Alternative designs have been proposed that achieve the mixed-resolution effect by combining two or more
projectors
A projector or image projector is an optical device that projects an image (or moving images) onto a surface, commonly a projection screen. Most projectors create an image by shining a light through a small transparent lens, but some newer types ...
with different
focal length
The focal length of an optical system is a measure of how strongly the system converges or diverges light; it is the inverse of the system's optical power. A positive focal length indicates that a system converges light, while a negative foca ...
s
While the high-resolution area of the original prototype was located at a fixed location, follow-up projects have obtained a movable focus area by using a
Tablet PC.
Patrick Baudisch
Patrick Baudisch is a computer science professor and the chair of the Human Computer Interaction Lab at Hasso Plattner Institute, Potsdam University. While his early research interests revolved around natural user interfaces and interactive devic ...
Patrick Baudisch
/ref> is the inventor of focus-plus-context screens (2000, while at Xerox PARC)
Advantages
* Allows users to leverage their foveal and their peripheral vision
* Cheaper to manufacture than a display that is high-resolution across the entire display surface
* Displays entirety and details of large images in a single view. Unlike approaches that combine entirety and details in software (fisheye views), focus-plus-context screens do not introduce distortion.
Disadvantages
* In existing implementations, the focus display is either fixed or moving it is physically demanding
References
;Notes
*
*
Yudhijit Bhattacharjee. In a Seamless Image, the Great and Small. In The New York Times, Thursday, March 14, 2002
*
*
*
External links
User interfaces
Computing output devices
Display technology
User interface techniques
{{comp-sci-stub