USAF 1951 resolution test targets/chart

First of all, we talk about the resolution target, which is classified on the official website of famous brand as a kind of measuring plate. 

But what we're talking about today is the USAF 1951 resolution chart.

The product is a kind of calibration chart, which is designed and manufactured according to the US military standard MIL-STD-150A.Its different resolution units use corresponding groups and element markers, and the corresponding resolution of each unit can be obtained by looking up the table. It has a wide range of applications, from the complex optical systems of aviation, aerospace and astronomical telescopes to the manufacturing and production of precision optical products commonly used in daily life. It is not only suitable for the imaging quality evaluation of various optical instruments and equipment ( such as stereo microscope, collimator and telescope, etc. ), but also very suitable for the imaging quality evaluation of various lenses and optical components ( such as aerial reconnaissance lens, aerial surveying and mapping lens, projection lens, microscopic objective lens, camera lens, camera lens and industrial camera lens, etc. ).

The resolution target has a series of horizontal and vertical lines, which can be used to determine the resolution of the imaging system. Six elements in each group are grouped ( horizontal and vertical line pairs ). Because the three lines are in one group, these test targets have a stronger ability to identify spurious resolutions. When a set of lines is blurred enough to cause the overlap part to look like more different flip lines are formed, the spurious resolution will appear. This phenomenon will lead to the misreading of the resolution of the optical system, because it is difficult to distinguish from the original line on the target. The spurious resolution will also cause the line to look one less than the original number of lines in a set of lines. Since the difference between the three lines and the two lines is easier to be noticed than the difference between the five lines and the four lines, it is easier to identify the spurious resolution if only three lines are in one group on the test target.

With the development of science and technology, the application of machine vision in all aspects has made great progress compared with the last century, and there are more tools and applications that are more convenient, simple and fast for resolution and distortion measurement. However, the resolution target is always the most effective and intuitive measurement correction application.