The effect of modulation transfer function on image quality

What are the factors that image flat panel detectors image? The modulation transfer function (MTF) is the ability to describe the system’s ability to reproduce the spatial frequency range of an imaged object. The ideal imaging system requires 100% reproduction of the imaged object details, but there must be varying degrees of attenuation in reality, so the MTF is always <1, which means that the imaging system cannot reproduce all the input images, in other words, through the imaging system.

The images obtained lose the contrast of the image to varying degrees. The larger the MTF value, the stronger the imaging system’s ability to reproduce the details of the imaged object. The MTF of the system must be determined. To evaluate the inherent imaging quality of a digital radiography system, it is necessary to calculate the pre-sampled MTF inherent to the system that is not subjectively affected.

The measurement results of international authoritative organizations show that the amorphous selenium flat panel detector has the best MTF value compared with the amorphous silicon flat panel detector, but the MTF of the amorphous silicon flat panel detector decreases rapidly when the spatial resolution increases. The amorphous selenium flat panel detector can still maintain a good MTF value, which is closely related to the imaging principle that the amorphous selenium flat panel detector directly converts the incident invisible X-ray photon into an electrical signal.