Electron tomographic reconstructions suffer from a number of artefacts arising from effects accompanying the processes of acquisition of a set of tilted projections of the specimen in a transmission electron microscope and from its subsequent computational handling. The most pronounced artefacts usually come from imprecise projection alignment, distortion of specimens during tomogram acquisition and from the presence of a region of missing data in the Fourier space, the "missing wedge". The ray artefacts caused by the presence of the missing wedge can be attenuated by the angular image filter, which attenuates the transition between the data and the missing wedge regions. In this work, we present an analysis of the influence of angular filtering on the resolution of averaged repetitive structural motives extracted from three-dimensional reconstructions of tomograms acquired in the single-axis tilting geometry.
The limited specimen tilting range that is typically available in electron tomography gives rise to a region in the Fourier space of the reconstructed object where experimental data are unavailable - the missing wedge. Since this region is sharply delimited from the area of available data, the reconstructed signal is typically hampered by convolution with its impulse response, which gives rise to the well-known missing wedge artefacts in 3D reconstructions. Despite the recent progress in the field of reconstruction and regularization techniques, the missing wedge artefacts remain untreated in most current reconstruction workflows in structural biology. Therefore we have designed a simple Fourier angular filter that effectively suppresses the ray artefacts in the single-axis tilting projection acquisition scheme, making single-axis tomographic reconstructions easier to interpret in particular at low signal-to-noise ratio in acquired projections. The proposed filter can be easily incorporated into current electron tomographic reconstruction schemes.
- MeSH
- artefakty MeSH
- Fourierova analýza MeSH
- krysa rodu rattus MeSH
- líska ultrastruktura MeSH
- mozeček ultrastruktura MeSH
- počítačové zpracování obrazu * MeSH
- poměr signál - šum MeSH
- pyl ultrastruktura MeSH
- tomografie elektronová metody MeSH
- Trypanosoma brucei brucei ultrastruktura MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Research Support, N.I.H., Extramural MeSH
