marker-free

marker-free performs alignment of electron tomography (ET) tilt series without fiducial markers to improve accuracy of 3D macromolecular tomogram reconstruction.

Key Features:

• Joint alignment framework: Leverages the interrelationship between projection parameters and landmarks to align tilt series without fiducial markers.
• Extrinsic and intrinsic integration: Integrates extrinsic (track-based) alignment with intrinsic (intensity-based) alignment in a single cohesive framework.
• Iterative refinement: Iteratively refines landmark localization and adjusts projection parameters until convergence.
• Robustness: Maintains alignment accuracy under varying initial conditions and extreme geometric changes, including pixel density changes between views.
• Experimental validation: Demonstrated improved alignment accuracy and reconstruction quality on three real datasets compared to state-of-the-art methods.

Scientific Applications:

• Marker-free tilt-series alignment: Aligns ET tilt series when fiducial markers are absent.
• Tomogram reconstruction improvement: Enhances 3D macromolecular tomogram reconstruction quality for electron tomography data.
• Method benchmarking: Enables comparative evaluation of alignment accuracy and reconstruction quality on experimental datasets.

Methodology:

The method jointly models projection parameters and landmark positions, combines extrinsic (track-based) and intrinsic (intensity-based) alignment, and iteratively refines landmark localization and projection parameters until convergence.