Where does fisheye collide?

In optics, a fisheye lens is an ultra-wide-angle lens that takes in a field of view approaching or exceeding 180 degrees and renders it with strong, deliberate barrel distortion, so straight lines near the edges bow outward and the image reads as a hemispherical view. Rather than preserving rectilinear geometry, it follows a mapping (such as equidistant projection) that trades straightness for coverage. Miyamoto's 1964 Fish eye lens set out the projection geometry that defines these lenses. The referent is a lens design characterized by its projection and field of view, unrelated to a paint crater or a data display.[1]

Unit

Field of view and projection mapping of the lens

Recovery means

Not applicable

Measured by

Specified by angular field of view and the projection function relating object angle to image radius

In human-computer interaction, a fisheye view is a focus-plus-context display technique that shows a region of interest in magnified detail while progressively shrinking and summarizing everything around it, so a user keeps local detail and global context on one screen. The name borrows the camera lens's distortion as a metaphor: a degree-of-interest function decides how much each item is enlarged or demoted. Furnas's 1986 Generalized fisheye views formalized the approach. The referent is an interface and layout method defined by a degree-of-interest function, distinct from the physical lens it is named after and from a coating crater.[2]

Unit

The degree-of-interest weighting applied across displayed items

Recovery means

Not applicable

Measured by

Defined by a degree-of-interest function and evaluated by user performance on navigation and search tasks