The gauge is intended to provide a means for measuring total image unsharpness as independently as practicable from the imaging system contrast sensitivity limitations. Further description and details of the gauge are provided in EN-462-5:1994.

The gauge can be used in conjunction with a contrast sensitivity measuring gauge, as described in Practice E 1647.

1.1 This practice covers the design and basic use of a gauge used to determine the total image unsharpness of radiographs and radioscopic systems.

1.2 This practice is applicable to radiographic and radioscopic imaging systems utilizing X-ray and gamma ray radiation sources.

1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.4 The gauge described can be used effectively with radiation energies up to 400 kv. When using energies in the megavolt range the results may not be completely satisfactory.

1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.