Speckle-Based Transmission and Dark-Field Imaging for Material Analysis with a Laboratory X-Ray Source

Area of Science:

• Medical Physics
• Materials Science
• X-ray Imaging

Background:

• Multimodal imaging offers advantages over conventional bright-field (BF) imaging by providing additional data.
• Speckle-based techniques, including transmission (T) and dark-field (DF) imaging, can be implemented using widely available laboratory X-ray devices.

Purpose of the Study:

• To investigate the implementation and usefulness of speckle-based T and DF X-ray imaging for material analysis.
• To evaluate the impact of object-to-detector distance (ODD) and analysis window size on image quality and material characterization.

Main Methods:

• Three speckle-based methods were applied to recover T and DF images from a sample of six materials.
• Contrast-to-noise ratio (CNR), linear attenuation, absorption, and diffusion coefficients were analyzed for different ODDs and analysis windows.
• The unified modulated pattern analysis method was identified as the most reliable for image recovery.

Main Results:

• CNR of T and DF images increased with larger analysis windows, while absorption and diffusion coefficients remained constant.
• CNR of T images decreased with increasing ODD due to noise.
• Absorption coefficients derived from T images were independent of ODD and method, proving useful for material discrimination.
• Diffusion coefficients varied with ODD, limiting their universal applicability.

Conclusions:

• Speckle-based T and DF X-ray imaging provide complementary information for material analysis.
• Absorption coefficients derived from T images serve as a universal parameter for material discrimination.
• DF imaging, despite ODD-dependent variations in diffusion coefficients, offers valuable insights for distinguishing materials.