Criteria
The minimum required resolution according to Johnson's criteria are expressed in terms of line pairs of image resolution across a target, in terms of several tasks:
- Detection, an object is present (1.0 +/– 0.25 line pairs)
- Orientation, symmetrical, asymmetric, horizontal, or vertical (1.4 +/– 0.35 line pairs)
- Recognition, the type object can be discerned, a person versus a car (4 +/– 0.8 line pairs)
- Identification, a specific object can be discerned, a woman versus a man, the specific car (6.4 +/– 1.5 line pairs)
These amounts of resolution give a 50 percent probability of an observer discriminating an object to the specified level.
Additionally, the line pairs refer to lines being displayed on an interlaced CRT monitor. Each line pair corresponds to 2 pixels of a film image, or an image displayed on an LCD monitor.
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—Hubert H. Humphrey (1911–1978)
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