This part of ISO 16371 specifies fundamental parameters of computed radiography systems with the aim of enabling satisfactory and repeatable results to be obtained economically. The techniques are based both on fundamental theory and test measurements. This part of ISO 16371 specifies the performance of computed radiography (CR) systems and the measurement of the corresponding parameters for the system scanner and storage phosphor imaging plate (IP). It describes the classification of these systems in combination with specified metal screens for industrial radiography. It is intended to ensure that the quality of images - as far as this is influenced by the scanner-IP system - is in conformity with the requirements of ISO 16371-2. This part of ISO 16371 relates to the requirements of film radiography defined in ISO 11699-1. This part of ISO 16371 defines system tests at different levels. More complicated tests are described, which allow the determination of exact system parameters. They can be used to classify the systems of different suppliers and make them comparable for users. These tests are specified as manufacturer tests. Some of them require special tools, which are usually not available in user laboratories. Therefore, simpler user tests are also described, which are designed for a fast test of the quality of CR systems and long term stability. There are several factors affecting the quality of a CR image including geometrical un-sharpness, signal/noise ratio, scatter and contrast sensitivity. There are several additional factors (e.g. scanning parameters), which affect the accurate reading of images on exposed IPs using an optical scanner. The quality factors can be determined most accurately by the manufacturer tests as described in this part of ISO 16371. Individual test targets, which are recommended for practical user tests, are described for quality assurance. These tests can be carried out either separately or by the use of the CR Phantom (Annex B). This CR Phantom incorporates many of the basic quality assessment methods and those associated with the correct functioning of a CR system, including the scanner, for reading exposed plates and in correctly erasing IPs for future use of each plate. The CR System classes in this part of ISO 16371 do not refer to any particular manufacturer's Imaging Plates. A CR system class results from the use of a particular imaging plate together with the exposure conditions – particularly total exposure – the scanner type and the scanning parameters.