3.2.11 window width and level—contrast (window width) and brightness (window level) adjustment of a digital image by changing how the Gray levels translate into displayed brightness levels. 3.2.12 signal-to-noise ratio (SNR)—quotient of mean value of the intensity (signal) and standard deviation of the intensity (noise). The SNR depends on the radiation dose and the DDA system properties. 3.2.13 contrast-to-noise ratio (CNR)—quotient of the difference in the mean values of the intensity (signal) in an area in the object subtracted from the mean value of the intensity of the background, and standard deviation of the intensity (noise). The CNR depends on the radiation dose and quality, thickness/ attenuation of the object and the DDA system properties. 3.2.14 basic spatial resolution (SRb)—indicates the smallest geometrical detail, which can be resolved using the DDA. It is similar to the effective pixel size/pitch and corresponds to 1⁄2 of the measured unsharpness. 3.2.15 ghosting—residual signal or image from a prior exposure in a current image. Signal or image can be negative or positive and may affect interpretation of the image. 3.2.16 bad pixel—a pixel identified with a performance outside of the specification range for a pixel of a DDA as defined in Practice E2597. 3.2.17 relevant cluster—a cluster with a cluster kernel pixel (CKP), where there are fewer than five good neighboring pixels surrounding this pixel as defined in Practice E2597.A CKP is a pixel that does not have sufficient good neighboring pixelstoperforminterpolation,andisthereforenotcorrectable.4. Significance and Use 4.1 This practice establishes the basic parameters for the application and control of the digital radiologic method. This practice is written so it can be specified on the engineering drawing, specification, or contract. It will require a detailed procedure delineating the technique or procedure requirements and shall be approved by the CEO