defocus
nounEtymology From de- + focus.
1
The process of going out of focus.
2
Engineering, Natural sciences, Optics, Physical sciences, Physics The distance by which the focal point is in front of (positive defocus) or beyond (negative defocus) the image or target surface.
- Fundamental to the concept of recovering the depth by measuring defocus is the relationship between the focused and the defocused images of a scene.2012, Subhasis Chaudhuri, A. N. Rajagopalan, Depth From Defocus: A Real Aperture Imaging Approach, page 16: