Study on modulation transfer characteristic of proximity X-ray imaging system

This article proposes a system-level optical modulation transfer characteristic detection methodology of proximity focusing X-ray imaging based on principle of contrast fitting to accurate assessment of proximity focusing X-ray imaging system. Firstly, theoretical modulation transfer characteristic of proximity X-ray imaging system is investigated from three aspects: the image-intensifier tubes, the ray source, imaging restriction. Then the generation process of ray source and imaging restriction of its spot size constraints was analyzed from the point of the wave theory. Next, as seen by quantum statistical, imaging noise origin was summarized. Based on the above restriction conditions, finally, system-level optical modulation transfer characteristic can be accurately fitted and being analyzed by different frequency of lead raster imaging was realtime online detected by fluorescence microscopy system. Time domain filtering is not only an effective way to reduce noise constraint but also avoid changing the original imagery information.