What does the modulation transfer function (MTF) of an image intensification system indicate?

The modulation transfer function (MTF) is a crucial aspect of assessing the performance of imaging systems, including image intensification systems. MTF quantifies the ability of an imaging system to reproduce (transfer) the various levels of detail from the object to the image, effectively measuring the resolution of the system. The values of MTF range from 0 to 1, where a value of 1 would indicate perfect resolution and detail transmission, meaning the system can reproduce high-frequency details of the object accurately in the image.

Given this context, stating that MTF is always less than 1 acknowledges the inherent limitations of any practical imaging system in achieving perfect resolution. Real-world factors, such as optical aberrations, noise, and physical limitations of the equipment, contribute to the decrease in resolution and image quality, resulting in MTF values that are indeed less than 1. Additionally, this understanding underlines the high-performance requirements for imaging systems, which strive for MTF values as close to 1 as possible but can never quite reach it due to these constraints.

The other options do not accurately reflect the nature of MTF. For instance, suggesting ranges between 1 and 2 or always being greater than 1 would imply an unrealistic situation