Resolution Testing/Reading: USAF-1951 Test Target
Resolution features of the USAF-1951 Resolution Chart are arranged in elements and groups. Each Element is made up of equally spaced bars; three horizontal and three vertical. Groups consist of six elements labeled 1 through 6. Groups are labeled by numbers in order of increasing frequency.
Note that Element 1 of even numbered groups is placed in the lower right hand corner and diagonally opposite Element 2 of the same Group. With this exception, all Elements are arranged in ascending order from top to bottom.
The resolution limit of a system is found by examining an image of the resolution test chart. Locate the Element of highest frequency where either horizontal or vertical lines are not indistinct. Note that the horizontal limit of resolution may indicate a different frequency than the limit of vertical resolution.
Using the APPLIED IMAGE Product Information Documents below, will allow translation from the Group and Element numbers to the line width or frequency. The necessary use of this tablet when using the standard USAF-1951 Resolution Test Target (T-20) inspired the development of the APPLIED IMAGE products USAF-1951 Direct Read Resolution Test Target (T-21) and the USAF-1951 Linear Direct Read Resolution Test Target (T-22). These two new unique APPLIED IMAGE targets provide direct labeling of resolution features on the targets.