Final answer:
Low contrast resolution is the term used to describe the ability of an imaging system to distinguish objects with similar densities.
Step-by-step explanation:
The ability to differentiate objects with similar densities in an image is known as low contrast resolution. This concept is fundamental in various imaging techniques such as those used in biology laboratories and astronomy. Resolution is the minimum distance between two objects needed for them to be seen as separate entities. The resolving power of a lens, according to the Rayleigh criterion, is based on the ability to distinguish this minimum distance. In biological imaging, high-resolution microscopes, including those with oil immersion lenses, provide the clarity and detail needed to distinguish intricate structures at microscopic levels. In astronomy, high resolution is essential to discern finely spaced details in celestial observations.