Digital Image Characteristics
Spatial Frequency and Spatial Resolution
In order to study the ability to resolve small oblects of an imaging system, it is necessary to understand spatial frequency and its relationship with spatial resolution .
The spatial resolution in Digital Imaging is mainly related to the size of the pixel . Anatomic detail is made up of small and big objects. The radiographic image describes these details as the difference in white and black brightness levels.
Small object of higher spatial frequency and large object of lower spatial frequency is | The imaging of small object (higher spatial frequency) is more difficult than large object (lower spatial frequency).
Spatial frequency is measured in line pair per millimeter (lp / mm) . A device is used to record it, which is called resolution test pattern .
An imaging system that can resolve more lp / mm (higher spatial frequency) has a more spatial resolution.
The ability of an imaging system to distinguish a particular spatial frequency is affected by its pixel size.
