title: Improving the accuracy of MTF measurement at low frequencies based on oversampled edge spread function deconvolution.
abstract: The modulation transfer function (MTF) of a radiographic system is often evaluated by measuring the system's edge spread function (ESF) using edge device. However, the numerical differentiation procedure of the traditional slanted edge method amplifies noises in the line spread function (LSF) and limits the accuracy of the MTF measurement at low frequencies. The purpose of this study is to improve the accuracy of low-frequency MTF measurement for digital x-ray imaging systems. An edge spread function (ESF) deconvolution technique was developed for MTF measurement based on the degradation model of slanted edge images. Specifically, symmetric oversampled ESFs were constructed by subtracting a shifted version of the ESF from the original one. For validation, the proposed MTF technique was compared with conventional slanted edge method through computer simulations as well as experiments on two digital radiography systems. The simulation results show that the average errors of the proposed ESF deconvolution technique were 0.11% ± 0.09% and 0.23% ± 0.14%, and they outperformed the conventional edge method (0.64% ± 0.57% and 1.04% ± 0.82% respectively) at low-frequencies. On the experimental edge images, the proposed technique achieved better uncertainty performance than the conventional method. As a result, both computer simulation and experiments have demonstrated that the accuracy of MTF measurement at low frequencies can be improved by using the proposed ESF deconvolution technique.
authors.affiliation: School of Precision Instrument and Optoelectronics Engineering, Tianjin University, Tianjin, China.|Center for Bioengineering and School of Electrical and Computer Engineering, University of Oklahoma, Norman, OK, USA.|Tianjin Key Laboratory of Biomedical Detecting Techniques and Instruments, Tianjin, China.
authors.forename: Zhongxing
authors.initials: Z
authors.lastname: Zhou
authors.affiliation: School of Precision Instrument and Optoelectronics Engineering, Tianjin University, Tianjin, China.|Tianjin Key Laboratory of Biomedical Detecting Techniques and Instruments, Tianjin, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Gao
authors.affiliation: School of Precision Instrument and Optoelectronics Engineering, Tianjin University, Tianjin, China.|Tianjin Key Laboratory of Biomedical Detecting Techniques and Instruments, Tianjin, China.
authors.forename: Huijuan
authors.initials: H
authors.lastname: Zhao
authors.affiliation: School of Precision Instrument and Optoelectronics Engineering, Tianjin University, Tianjin, China.|Tianjin Key Laboratory of Biomedical Detecting Techniques and Instruments, Tianjin, China.
authors.forename: Lixin
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Center for Bioengineering and School of Electrical and Computer Engineering, University of Oklahoma, Norman, OK, USA.
authors.forename: Liqiang
authors.initials: L
authors.lastname: Ren
authors.affiliation: Center for Bioengineering and School of Electrical and Computer Engineering, University of Oklahoma, Norman, OK, USA.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Li
authors.affiliation: Center for Bioengineering and School of Electrical and Computer Engineering, University of Oklahoma, Norman, OK, USA.
authors.forename: Muhammad U
authors.initials: MU
authors.lastname: Ghani
authors.affiliation: School of Precision Instrument and Optoelectronics Engineering, Tianjin University, Tianjin, China.
authors.forename: Ting
authors.initials: T
authors.lastname: Hao
authors.affiliation: Center for Bioengineering and School of Electrical and Computer Engineering, University of Oklahoma, Norman, OK, USA.
authors.forename: Hong
authors.initials: H
authors.lastname: Liu
mesh_terms: D003198:Computer Simulation; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D011856:Radiographic Image Enhancement / Q000592:standards*; D015203:Reproducibility of Results
keywords: Digital x-ray imaging; deconvolution; edge spread function; modulation transfer function