Variable focusing of electron microscopy image data utilizing origin-centered discrete fractional fourier transform
AssigneeLester F. Ludwig
InventorLester F. Ludwig
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Abstract
Computer-implemented arrangements for adjusting the focus in original electron microscope image data are described. In an implementation, an origin-centered fractional Fourier transform operation and an origin-centered phase restoration operation, both responsive to a provided fractional power value, are collectively applied to original electron microscope image data to produce computationally-focused image data. A parameter adjuster is used to provide a range of variation of the power value, and can be adjusted by a user or under the direction of a control system. The fractional Fourier transform operation and the phase restoration operation can be realized by at least one numerical algorithm and can comprise an approximation.
Claims20
A computer-implemented method for adjusting the focus in original electron microscope image data, the method comprising:
- obtaining original electron microscope image data comprising a plurality of spatially-indexed amplitude values, and further comprising a center located relative to the plurality of spatially-indexed amplitude values;
- providing a fractional power parameter associated with a fractional Fourier transform operation;
- calculating approximated centered two-dimensional discrete phase restoration information responsive to the fractional power value;
- calculating an approximated centered two-dimensional fractional Fourier transform operation responsive to the fractional power value;
- operating on the original electron microscope image data with the approximated centered two-dimensional phase restoration information and the approximated centered two-dimensional fractional Fourier transform operation to produce computationally-focused image data;
- wherein the focus plane of the computationally-focused image data is responsive to the fractional power parameter.
A system for adjusting focus in original electron microscope image data, the system comprising:
- a numerical centered two-dimensional phase restoration operation for approximately restoring phase information associated with the original electron microscope image data to produce computationally-focused image data, the centered two-dimensional phase restoration operation responsive to a fractional power;
- a numerical centered two-dimensional fractional Fourier transform operation for applying at least one approximated centered two-dimensional fractional Fourier transform operation responsive to the fractional power;
- a parameter adjuster for providing a range of variation of the at least one fractional power;
- wherein the numerical centered two-dimensional phase restoration operation and numerical centered two-dimensional fractional Fourier transform operation are applied to the original electron microscope image data, resulting in computationally-focused image data.
Dependencies are inferred from the claim text.