Resolution performance evaluation method for digital X-ray imaging system

Abstract

The invention provides a resolution performance evaluation method for a digital X-ray imaging system. The method comprises the steps that (1) a plurality of incision images are continuously collected; (2) superposition averaging is performed on the collected incision images, afterwards, incision boundary detection is performed on the averaged incision images, and an incision boundary straight line is obtained through line fitting; (3) an incision tilt angle is obtained, and an oversampling ESF curve is constructed; (4) the oversampling ESF curve is de-noised by the adoption of a monotonic curve fitting method; (5) a suitable translation distance is selected, a real ESF curve and a difference curve of a translation distance result of the real ESF curve are constructed, and Fourier transform is performed on the real ESF curve and the difference curve to obtain sinc functions; (6) suitable translation is performed on an actual oversampling ESF curve, and then subtraction is performed between the actual oversampling ESF curve and the original oversampling ESF curve to obtain a symmetrical oversampling curve; (7) a system modulation transfer function is solved through a deterioration model formula under a frequency domain. According to the resolution performance evaluation method, compared with a traditional incision measuring method, a more accurate MTF curve can be obtained.

Description

Technical field [0001] The invention belongs to the fields of biomedical engineering and computer, and relates to a method for evaluating the resolution performance of a digital X-ray imaging system. Background technique [0002] Modulation Transfer Function (MTF) is a transfer function of modulation degree, a quantitative description of the spatial frequency transmission characteristics of a linear image system, and an important development in image evaluation methods. 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 indicator has become an important image evaluation method that radiography workers and researchers pay attention to. At the same time, MTF is also a necessary...

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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