What is the USAF target resolution test for 1951?

USAF 1951 Resolution Test Chart

The USAF 1951 resolution test chart is a standardized tool used to measure the resolving power of optical systems such as cameras, microscopes, and telescopes. Developed by the United States Air Force in 1951, this chart is still widely employed to test the clarity and sharpness of lens systems and imaging devices.

The design of the chart comprises a series of patterns consisting of three-bar targets of varying sizes and orientations. Each set of bars is grouped into elements and groups of progressively smaller size, defined by their dimension and frequency.

How to Use the USAF 1951 Target

• Place the USAF 1951 chart at an appropriate distance from the optical device being tested.
• Adjust the focus of the device until the image of the chart seen through the device is as sharp as possible.
• Determine the highest group and element number where the three bars (horizontal, vertical, and diagonal) can be distinctly resolved.

To interpret the results, each group and element on the chart corresponds to specific line pairs per millimeter (lp/mm), which defines the spatial resolution of the system. The observer identifies the group and element where the lines can be distinctly separated, which directly correlates with the system's resolving power in terms of line pairs per millimeter.

It is commonly used in quality control, research, and calibrating systems to ensure consistent and reliable performance.

While the USAF 1951 chart has been widely used, it has some limitations in assessing modern, high-resolution imaging systems. As technology advanced, newer targets and methods have been developed for more rigorous testing of such systems.