X-ray analyzer-based imaging(ABI) is a powerful phase-sensitive technique that can provide a wide dynamic range of density and extract useful physical properties of the sample. It derives contrast from x-ray absorptio...X-ray analyzer-based imaging(ABI) is a powerful phase-sensitive technique that can provide a wide dynamic range of density and extract useful physical properties of the sample. It derives contrast from x-ray absorption, refraction, and scattering properties of the investigated sample. However, x-ray ABI setups can be susceptible to external vibrations, and mechanical imprecisions of system components, e.g., the precision of motor, which are unavoidable in practical experiments. Those factors will provoke deviations of analyzer angular positions and hence errors in the acquired image data.Consequently, those errors will introduce artefacts in the retrieved refraction and scattering images. These artefacts are disadvantageous for further image interpretation and tomographic reconstruction. For this purpose, this work aims to analyze image artefacts resulting from deviations of analyzer angular positions. Analytical expressions of the refraction and scattering image artefacts are derived theoretically and validated by synchrotron radiation experiments. The results show that for the refraction image, the artefact is independent of the sample’s absorption and scattering signals. By contrast, artefact of the scattering image is dependent on both the sample’s refraction and scattering signals, but not on absorption signal.Furthermore, the effect of deviations of analyzer angular positions on the accuracy of the retrieved images is investigated,which can be of use for optimization of data acquisition. This work offers the possibility to develop advanced multi-contrast image retrieval algorithms that suppress artefacts in the retrieved refraction and scattering images in x-ray analyzer-based imaging.展开更多
We present a moment-based alternative approach to retrieve multiple scattering contrasts from x-ray analyzer-based imaging. By use of the properties of moments of convolutions, the multiple-image radiography approach ...We present a moment-based alternative approach to retrieve multiple scattering contrasts from x-ray analyzer-based imaging. By use of the properties of moments of convolutions, the multiple-image radiography approach is theoretically validated. Furthermore, higher order moments of the object scattering distribution, inaccessible in multiple-image radiography, are simultaneously provided by this alternative approach. It is experimentally demonstrated that the skew and kurtosis information related to the distribution of sub-pixel features within the object can be obtained from those complementary contrasts. Finally, the sensitivity of the retrieved multiple scattering contrasts is investigated experimentally. The finding that the sensitivity is inversely proportional to the square root of the detected photon number essentially indicates that the retrieval of moments with an order higher than two can be achieved without increasing exposure time or dose. The presented alternative approach provides an access to the exploitation of multiple scattering contrasts, which is expected to be useful in biomedical research, materials science, security screening, etc.展开更多
Recently,a novel three-image algorithm has been proposed to retrieve the sample’s absorption,refraction,and scattering properties in x-ray analyzer-based imaging.The feasibility of the three-image algorithm was valid...Recently,a novel three-image algorithm has been proposed to retrieve the sample’s absorption,refraction,and scattering properties in x-ray analyzer-based imaging.The feasibility of the three-image algorithm was validated by synchrotron radiation experiments.However,it is unclear yet whether the estimated refraction and scattering signals are biased or not and how the analyzer angular position affects the biases in the estimated signals.For this purpose,the biases of the extracted refraction and scattering signals are theoretically derived for the three-image algorithm.The theoretical models are further confirmed by numerical experiments.The results show that both the estimated refraction and scattering signals are biased,and the biases are strongly dependent on the analyzer angular position.Besides,the biases also show dependence on the sample’s refraction and scattering properties locally.Those results can be used as general guidelines to optimize experimental parameters for bias reduction and accurate imaging of different features within the sample.展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos. U1532113, 11475170, and 11905041)the Fundamental Research Funds for the Central Universities (Grant No. PA2020GDKC0024)Anhui Provincial Natural Science Foundation, China (Grant No. 2208085MA18)。
文摘X-ray analyzer-based imaging(ABI) is a powerful phase-sensitive technique that can provide a wide dynamic range of density and extract useful physical properties of the sample. It derives contrast from x-ray absorption, refraction, and scattering properties of the investigated sample. However, x-ray ABI setups can be susceptible to external vibrations, and mechanical imprecisions of system components, e.g., the precision of motor, which are unavoidable in practical experiments. Those factors will provoke deviations of analyzer angular positions and hence errors in the acquired image data.Consequently, those errors will introduce artefacts in the retrieved refraction and scattering images. These artefacts are disadvantageous for further image interpretation and tomographic reconstruction. For this purpose, this work aims to analyze image artefacts resulting from deviations of analyzer angular positions. Analytical expressions of the refraction and scattering image artefacts are derived theoretically and validated by synchrotron radiation experiments. The results show that for the refraction image, the artefact is independent of the sample’s absorption and scattering signals. By contrast, artefact of the scattering image is dependent on both the sample’s refraction and scattering signals, but not on absorption signal.Furthermore, the effect of deviations of analyzer angular positions on the accuracy of the retrieved images is investigated,which can be of use for optimization of data acquisition. This work offers the possibility to develop advanced multi-contrast image retrieval algorithms that suppress artefacts in the retrieved refraction and scattering images in x-ray analyzer-based imaging.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11475170,U1532113,and 11905041)the Fundamental Research Funds for the Central Universities,China(Grant No.PA2020GDKC0024)。
文摘We present a moment-based alternative approach to retrieve multiple scattering contrasts from x-ray analyzer-based imaging. By use of the properties of moments of convolutions, the multiple-image radiography approach is theoretically validated. Furthermore, higher order moments of the object scattering distribution, inaccessible in multiple-image radiography, are simultaneously provided by this alternative approach. It is experimentally demonstrated that the skew and kurtosis information related to the distribution of sub-pixel features within the object can be obtained from those complementary contrasts. Finally, the sensitivity of the retrieved multiple scattering contrasts is investigated experimentally. The finding that the sensitivity is inversely proportional to the square root of the detected photon number essentially indicates that the retrieval of moments with an order higher than two can be achieved without increasing exposure time or dose. The presented alternative approach provides an access to the exploitation of multiple scattering contrasts, which is expected to be useful in biomedical research, materials science, security screening, etc.
基金National Natural Science Foundation of China(Grant Nos.U1532113,and 11475170)the Fundamental Research Funds for the Central Universities,China(Grant No.PA2020GDKC0024).
文摘Recently,a novel three-image algorithm has been proposed to retrieve the sample’s absorption,refraction,and scattering properties in x-ray analyzer-based imaging.The feasibility of the three-image algorithm was validated by synchrotron radiation experiments.However,it is unclear yet whether the estimated refraction and scattering signals are biased or not and how the analyzer angular position affects the biases in the estimated signals.For this purpose,the biases of the extracted refraction and scattering signals are theoretically derived for the three-image algorithm.The theoretical models are further confirmed by numerical experiments.The results show that both the estimated refraction and scattering signals are biased,and the biases are strongly dependent on the analyzer angular position.Besides,the biases also show dependence on the sample’s refraction and scattering properties locally.Those results can be used as general guidelines to optimize experimental parameters for bias reduction and accurate imaging of different features within the sample.
