Evaluation Method of Resolution Performance of Digital X-ray Imaging System

Abstract

The invention provides a resolution performance evaluation method of a digital X-ray imaging system, which includes: (1) continuously collecting multiple knife-edge images; (2) superimposing and averaging the collected multiple knife-edge images, and then performing knife-edge boundary detection on the averaged knife-edge images , and use straight line fitting to obtain the knife edge boundary line; ③ Obtain the inclination angle of the knife edge to construct the oversampling ESF curve; ④ Use the monotonic curve fitting method to de-noise the oversampling curve; ⑤ Select the appropriate translation distance to construct the real ESF curve and its Translate the difference curve of the distance result, and obtain the sinc function from its Fourier transform; ⑥ Properly translate the actual oversampling ESF curve, and then subtract it from the original oversampling curve to obtain a symmetrical oversampling curve; ⑦Using the frequency The degradation model formula in the domain solves the system modulation transfer function. The invention can obtain a more accurate MTF curve than the traditional knife edge measurement method.

Description

Technical field [0001] The invention belongs to the fields of biomedical engineering and computers, and relates to a resolution performance evaluation method of a digital X-ray imaging system. Background technique [0002] The modulation transfer function (ModulationTransferFunction, MTF) is the transfer function of the modulation degree, which is a quantitative description of the spatial frequency transmission characteristics of the linear image system, and is an important progress in the image evaluation method. Previously, qualitative description indicators, such as image density, contrast, sharpness, resolution, and distortion, were commonly used to evaluate the image quality of imaging systems, but the results were greatly affected by personal subjective factors. In recent years, with the rapid development of digital X-ray imaging technology, MTF as an objective index has become an important image evaluation method that radiographers and researchers pay attention to. A...

AI Technical Summary

Problems solved by technology

The present invention aims at the problem of low-frequency MTF measurement precision drop caused by noise amplification caused by the derivation process of the oversampled ESF curve in the traditional knife-edge method, and proposes a deconvolution method for the oversampled ESF curve, avoiding the derivation process of obtaining the LSF curve, In this way, a more accurate MTF curve can be obtained than the traditional knife-edge measurement method

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