Improving visibility of X-ray phase-contrast imaging with Wiener filtering
| Autor: | Shao-run Gong, Feng Gao, Zhongxing Zhou |
|---|---|
| Rok vydání: | 2010 |
| Předmět: |
Point spread function
Deblurring Radiation Image quality business.industry Phantoms Imaging Visibility (geometry) Wiener filter Models Theoretical Condensed Matter Physics Noise (electronics) Radiographic Image Enhancement symbols.namesake Optics symbols Radiology Nuclear Medicine and imaging Computer Simulation Electrical and Electronic Engineering business Instrumentation Image resolution Algorithms Mathematics Interpolation |
| Zdroj: | Journal of X-ray science and technology. 18(3) |
| ISSN: | 1095-9114 |
| Popis: | To investigate the degrading effects of the physical parameters on the in-line X-ray phase-contrast imaging (XPCi), a simulation tool based on the Fresnel/Kirchhoff diffracti on integral was firstly developed with comprehensively cons idering effects of the source-to-sample (S-S) and sample-to-detector (S-D) distances, the practical characteristics of a pol ychromatic and finite size source, the point spread function (PSF) of the fluorescent screen and the spatial resolution of the detecto r on the theoretical phase-contrast pattern. By a comparison between the simulative profile and the experimental one unde r the commonly-used parameters, an acceptable consistency has been demonstrated in despite of the deviation between the theoretically-predicted contrast (0.188) and the origina l experimental one (0.12). From the simulations, it is apparently observed that the fine interference pattern has been severel y degraded by the finite spatial resolution, and will inevita bly be further deteriorated by the system noise in practice. Since the image quality of the X-ray phase-contrast imaging is strongly dependent on the physical parameters of the system, a model-based deblurring procedure to upgrade the image visibility is preferably desired. As a simple restoration way, a Wiener fil ter was then introduced to offer an optimal tradeoff between the contrast preservation and the noise suppression. Finally, to minimize the deviation resulting from the finite spatial r esolution, one-dimensional interpolation was performed by positioning the set square at a tiny angle to the vertical direction. Th e result after the Wiener-filtering-based deblurring has shown a con siderably improved profile visibility: the processed exper imental contrast (0.156) increased by 30% as compared to the original one (0.12) in company with the increase in the signal-to-noise ratio (SNR) by 0.9dB. With the trend of the post-filtered expe rimental contrast to the theoretical one, it could be motiva ted that higher visibility would be achieved with the introduction of more precise blurring mask and noise spectrum estimation. |
| Databáze: | OpenAIRE |
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