Shortly there are three main image quality parameter with an X-Ray image

Sharpness measures resolution perpendicular to the beam (spatial resolution - SR)

Contrast measures resolution in direction of the beam (contrast resolution - CR) high contrast resolution == low noise

Time to get a sufficient image quality in relation to SR and CR

The amount of X-Ray photons define the X-Ray triangle with the three corners for optimation:



The different applications and markets define their areas within the triangle:

As the previous posting is too simple, here is a more complete version. In BOLD are the Image Quality Parameter and in the next line the measurement method and IQI.

1. SRB Basic Spatial Resolution
duplex wire gauge, linepair gauge, MTF

2. CS Contrast Sensitivity
stepwedge, holetype penetrameter, wire-sets, plates with recesses

3. SNR Signal to Noise Ratio
statistic tool within the image processing software

4. DR Dynamic Range
stepwedge, holetype penetrameter, wire-sets

5. Image LAG (in image sequence)
software tool

6. Internal Scatter Radiation
block of Tungsten

7. Geometrical Distortion (not relevant for DDAs and film, only for CR and Image Intensifier)
software tool

8. Image Imperfections (Bad Pixel, dust/fussel, dirt, …)
software tools

9. Efficiency (depended to energy (keV))
software tools

There are a few standards for the proper IQIs.
In Europe and ISO most of the IQIs are defined in ISO19232
ISO19232-1 Wire (contrast and spatial resolution)
ISO19232-2 Step Hole (contrast and spatial resolution)
ISO19232-5 Duplex Wire gauge (spatial resolution) - identical to ASTM E2002
In ASTM E07 we have
E1025 and in annex of E1742 holetype penetrameter (contrast and spatial resolution)
E1647 Plates with recesses (contrast resolution)
E2002 Duplex Wire Gauge ((spatial resolution) - identical to ISO19232-5
E747 Wire sets (contrast and spatial resolution) - similar to ISO19232-1
E746 Multi Hole Plates (contrast and spatial resolution)
E2737 Duplex Plate with E1025 and E2002 IQIs
E2737 Five Groove Wedge (continous wedge with five grooves)
E2445 CR Phantom (plate with ten differents IQIs or gauges) - identical to ISO 16371-1 or EN 14784-1