Method for accurately measuring modulation transfer function of digital X-ray imaging system

Abstract

The invention belongs to the fields of biomedical engineering and computers and relates to a method for accurately measuring a modulation transfer function (MTF) of a digital X-ray imaging system. The method comprises the steps of: placing a simulated fat body, collecting a plurality of images, and calculating a noise power spectrum of integral noises of the system; placing a lead plate for covering a detector, acquiring a plurality of images and calculating an electronic noise power spectrum of the system; placing a line pair card, collecting a plurality of images, and overlaying and averaging all the images to obtain an average image of the line pair card; acquiring a strength profile map by means of the average image of the line pair card, and calculating an MTF value corresponding to an integer spatial frequency of the line pair card; and calculating the noise power spectrum and a related coefficient eta of the MTF by utilizing a linear regression method to obtain an MTF change curve of the imaging system under a spatial frequency range. The method provided by the invention can be used for realizing the accurate measurement of the MTF of the digital X-ray imaging system and provides powerful conditions for further and all-around evaluation of the performance of the radiological imaging system.

Description

technical field [0001] The invention belongs to the fields of biomedical engineering and computers, and relates to a method for measuring a modulation transfer function of a digital X-ray imaging system. Background technique [0002] Modulation transfer function (Modu1ation Transfer Function, MTF) is the transfer function of modulation degree, which is a quantitative description of the spatial frequency transmission characteristics of linear imaging systems, and is an important progress 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 index has become an important image evaluation method that radiographers and researchers pay attention to. ...

AI Technical Summary

Problems solved by technology

[0008] The gist of the present invention is to solve the problem of modulation transfer function measurement errors caused by factors such as knife-edge processing accuracy, measurement method accuracy, and differences in the experience of measuring personnel when using the knife-edge method to measure the modulation transfer function in the performance evaluation of a digital X-ray imaging system. A new method for accurate measurement of the modulation transfer function of the digital X-ray imaging system realizes the accurate measurement of the modulation transfer function of the digital X-ray imaging system and provides a powerful condition for further comprehensive evaluation of the performance of the radiological imaging system

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