RADIOGRAPHIC CALIBRATION

摘要

By providing holes (32, 45, 46, 47, 51, 52, 53) in hole groups (31, 41, 42, 43) (generally in a triangular orientation for a range of incremental hole sizes) it is possible to provide an image quality indicator which provides a minimum defect size which can be determined based upon contrast sensitivity and spatial resolution. Each hole (32, 45, 46, 47, 51, 52, 53) has a diameter (d) which is the same as its depth (d) and the three holes (32, 45, 46, 47, 51, 52, 53) in a hole group (31, 41, 42, 43) have a spacing (s) the equivalent of the hole diameter (d) and depth (d). The value of the spacing (s), diameter (d) and depth (d) is defined as a calibration value and is generally a percentage of the material thickness.