SFS-2
It seems like you are describing a set of test objects designed for a quick and easy assessment of imaging performance. These objects are intended to be used regularly to monitor and check various aspects of imaging performance, with a specific focus on identifying potential deterioration.
By regularly measuring and recording certain parameters or numbers associated with the imaging process, this set of test objects can help in detecting any trends or signs of degradation in imaging performance over time. This proactive approach to quality control allows for early identification of issues, facilitating timely intervention or maintenance to ensure consistent and high-quality imaging results.