— The Stuart Hunt & Associates Team.
Image Quality Indicator for evaluation of Basic Spatial Resolution
The Duplex IQI is useful for many X-ray applications, especially in digital X-ray. Designed for evaluating total image unsharpness of X-ray
films now it is mainly used for basic spatial resolution evaluation of digital images according to EN 13068 (Radioscopy), ISO 16371or
ASTM E2445 (CR – Computed Radiography with Imaging Plates), ASTM E2446 and ASTM E2597 (characterization of CR systems and DDAs)
and ASTM E2737 (Long term stability of DDAs). But also for digital radiology of welds ISO 17636-2 ()
Image valuation with Duplex Wire Type IQI
In radiography the wire pair with largest diameter d has to be identified, which cannot be separated visually. The radiographic film may be
magnified up to 4X. In digital radiology the separation between wires (Dip) is evaluated. The wire pair with largest d, showing Dip less than
20 percent of the wire pair contrast, identifies total image unsharpness (U = 2d) and basic spatial resolution (SRb = d) of digital image.
Specification
| DD | d (μm) | UT (μm) | SRb (μm) | LP (1/mm) |
| D 1 | 800 | 1600 | 800 | 0.63 |
| D 2 | 630 | 1260 | 630 | 0.79 |
| D 3 | 500 | 1000 | 500 | 1 |
| D 4 | 400 | 800 | 400 | 1.25 |
| D 5 | 320 | 640 | 320 | 1.56 |
| D 6 | 250 | 500 | 250 | 2 |
| D 7 | 200 | 400 | 200 | 2.5 |
| D 8 | 160 | 320 | 160 | 3.13 |
| D 9 | 130 | 260 | 130 | 3.85 |
| D 10 | 100 | 200 | 100 | 5 |
| D 11 | 80 | 160 | 80 | 6.25 |
| D 12 | 63 | 126 | 63 | 7.94 |
| D 13 | 50 | 100 | 50 | 10 |
| D 14 | 40 | 80 | 40 | 12.5 |
| D 15 | 32 | 63 | 32 | 15.9 |
| D 16 | 25 | 50 | 25 | 20 |
| D 17 | 20 | 40 | 20 | 25 |
| DD | Duplex Wire Pair Number |
| d | Wire Diameter and Spacing |
| UT | Corresponding Unsharpness |
| SRb | Corresponding Basic Spatial Resolution |
| LP | Corresponding Line Pair Value (LP per mm) |
