Geometric blur (illustrations)

Case contributed by Lachlan McKay
Diagnosis not applicable
Illustration
Figure 1: Focal
spot size
Figure 2: Object
to image distance
Figure 3: Source
to object distance
Download
Info

Figures 1, 2 and 3 demonstrate a reduction in geometric blur through;

  • decreasing focal spot size

  • decreasing object to image distance (OID)

  • increasing source to object distance (SOD)

Original illustrations by Lachlan McKay.

Case Discussion

Geometric blur is a type of blurring created by the relationship between the focal spot size and positioning of the source, patient (object) and detector (image) 1.

It may be described through the equation:

  • Geometric blur = f * (OID / SOD)

    • where f = focal spot size, OID = object to image distance and SOD = source to object distance.

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