geometric unsharpness
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pe·num·bra
(pĕ-nŭm'bră)1. radiology The blurred margin of an image.
2. radiation physics The region at the edges of a radiation beam over which a rapid change in dosage rate occurs.
Synonym(s): geometric unsharpness.
Synonym(s): geometric unsharpness.
[Mod. L., fr. L. paene, almost, + umbra, shadow]
pe·num·bra
(pĕ-nŭm'bră)1. radiology the blurred margin of an image.
2. radiation physics the region at the edges of a radiation beam over which a rapid change in dosage rate occurs.
Synonym(s): geometric unsharpness.
Synonym(s): geometric unsharpness.
[Mod. L., fr. L. paene, almost, + umbra, shadow]