Biomedical subjects

Yasutoshi Kotaka

Publications and source records attributed to Yasutoshi Kotaka.

2 recordsLinked to original sources

PubMed2005

An expanded approach to noise reduction from high-resolution STEM images based on the maximum entropy method.

An expanded use of the maximum entropy method (MEM) is suggested to reduce noise from an experimental high-angle annular dark-field (HAADF) scanning transmission electron microscope (STEM) image. The MEM is combined with an estimate of the standard deviation of noise from an experimental HAADF STEM image and low-pass filtering using the information limit for an incoherent STEM image. Consequently, the present method has just one parameter of a Lagrange multiplier. It is demonstrated that the present method can reduce noise efficiently in high-resolution HAADF STEM images.

Journal Article↗

PubMed2005

Precise measurement of third-order spherical aberration using low-order zone-axis Ronchigrams.

A method for the measurement of third-order spherical aberration coefficients (C(s)) is suggested, using low-order zone-axis Ronchigrams of a crystalline material. The validity of the method is confirmed using simulated and experimental Ronchigrams taken with various probe-forming lens configurations. The precision of the measured C(s) value is drastically improved compared with that obtained from the power spectrum-analysis method. In addition, a method for roughly estimating defocus values is presented.

Journal Article↗