Evaluation of Spatial Performance in X-ray Imaging Detectors: CTF, MTF, LSF, and ESF Analysis

Abstract

This study was conducted at the University of Trieste's Department of Physics, focusing on the comprehensive characterization of the spatial response of an X-ray imaging detector. The primary objective was to measure and analyze the Contrast Transfer Function (CTF), Modulation Transfer Function (MTF), Line Spread Function (LSF), and Edge Spread Function (ESF) to evaluate the detector's performance. Using a well-calibrated X-ray source, various test patterns and phantoms were imaged to acquire data. The CTF was assessed by analyzing the contrast response of the detector to a series of bar patterns with varying spatial frequencies. The MTF was derived from the Fourier transform of the LSF, which was obtained by scanning a narrow slit across the detector. The LSF provided detailed insights into the detector's response to a sharp line source. The ESF was measured by imaging a sharp edge, and subsequent differentiation yielded the LSF. These measurements were conducted under controlled conditions to ensure accuracy and repeatability. The results highlighted the spatial resolution capabilities and limitations of the X-ray imaging detector, providing a detailed understanding of its performance metrics. This comprehensive characterization is crucial for optimizing detector design and improving image quality in various applications, ranging from medical imaging to industrial inspection.