A single-image retrieval method for edge illumination X-ray phase-contrast imaging: Application and noise analysis.
OBJECTIVE
Edge illumination (EI) X-ray phase-contrast imaging (XPCI) has been under development at University College London in recent years, and has shown great potential for both laboratory and synchrotron applications. In this work, we propose a new acquisition and processing scheme. Contrary to existing retrieval methods for EI, which require as input two images acquired in different setup configurations, the proposed approach can retrieve an approximate map of the X-ray phase from a single image, thus significantly simplifying the acquisition procedure and reducing data collection times.


METHODS
The retrieval method is analytically derived, based on the assumption of a quasi-homogeneous object, i.e. an object featuring a constant ratio between refractive index and absorption coefficient. The noise properties of the input and retrieved images are also theoretically analyzed under the developed formalism. The method is applied to experimental synchrotron images of a biological object.


RESULTS
The experimental results show that the method can provide high-quality images, where the "edge" signal typical of XPCI images is transformed to an "area" contrast that enables an easier interpretation of the sample geometry. Moreover, the retrieved images confirm that the method is highly stable against noise.


CONCLUSIONS
We anticipate that the developed approach will become the method of choice for a variety of applications of EI XPCI, thanks to its ability to simplify the acquisition procedure and reduce acquisitions time and dose to the sample. Future work will focus on the adaptation of the method to computed tomography and to polychromatic radiation from X-ray tubes.
Department of Medical Physics and Biomedical Engineering, University College London, London, UK; Research Complex at Harwell, Oxford Harwell Campus, Didcot, UK. Electronic address: p.diemoz@ucl.ac.uk.
Paul C
PC
Diémoz
Department of Medical Physics and Biomedical Engineering, University College London, London, UK; Research Complex at Harwell, Oxford Harwell Campus, Didcot, UK.
Fabio A
FA
Vittoria
Department of Medical Physics and Biomedical Engineering, University College London, London, UK.
Charlotte K
CK
Hagen
Department of Medical Physics and Biomedical Engineering, University College London, London, UK.
Marco
M
Endrizzi
Institute for Clinical Radiology, Ludwig-Maximilians-University, Munich, Germany; Department of Physics, Ludwig-Maximilians-University, Garching, Germany.
Paola
P
Coan
European Synchrotron Radiation Facility, Grenoble, France.
Alberto
A
Bravin
Diamond Light Source, Harwell Oxford Campus, Didcot, UK.
Ulrich H
UH
Wagner
Diamond Light Source, Harwell Oxford Campus, Didcot, UK.
Christoph
C
Rau
Research Complex at Harwell, Oxford Harwell Campus, Didcot, UK; London Centre for Nanotechnology, London, UK.
Ian K
IK
Robinson
Department of Medical Physics and Biomedical Engineering, University College London, London, UK; Research Complex at Harwell, Oxford Harwell Campus, Didcot, UK.
Alessandro
A
Olivo
D007091:Image Processing, Computer-Assisted; D008029:Lighting; D011859:Radiography / Q000295:instrumentation*; D059629:Signal-To-Noise Ratio; D017356:Synchrotrons; D014934:Wood; D014965:X-Rays
Edge illumination; Fast imaging; Phase retrieval; Phase-contrast imaging