The method is for automatic astigmatism correction of a lens system. A first image is provided that is not in focus at a first stigmator setting of a set of lenses. A calculating device calculates a corresponding first Fourier spectrum image. A distribution and direction of pixels of the Fourier spectrum image are determined by calculating a first vector and a second vector. The first vector is compared with the second vector. The lens system is changed from a first stigmator setting to a second stigmator setting to provide a second image. A corresponding Fourier spectrum image is calculated. The distribution and direction of pixels of the second Fourier spectrum image is determined by calculating a third vector and a fourth vector. The third vector is compared to the fourth vector. The image that has the lowest vector ratio is selected.

Methods for correcting one or more image aberrations in an electron microscopy image, including cryo-EM images, are provided. The method includes obtaining a plurality of electron microscope (EM) images of an internal reference grid sample having one or more known properties, the plurality of electron microscope images obtained for a plurality of optical conditions and for a plurality of coordinated beam-image shifts. The method may also include, among other features, determining an aberration correction function that predicts aberrations for every point in the imaged area using kernel canonical correlation analysis (KCCA).

The present disclosure provides a cryo-electron microscopy image processing method and apparatus, a terminal, and a storage medium. The cryo-electron microscopy image processing method includes: obtaining a cryo-electron microscopy image; encoding the cryo-electron microscopy image into latent variables through an encoder; converting the latent variables into an atomic model structure through a decoder; correcting the atomic model structure using a loss function to obtain a corrected atomic model structure, where the loss function includes a bond length constraint loss function, a clash constraint loss function, and a spring constraint loss function; and converting, through a projector module, the corrected atomic model structure into a density map represented by Gaussian spheres, and projecting the density map to obtain a projection image.

A charged particle beam apparatus with improved depth of focus and maintained/improved resolution has a charged particle source, an off-axis illumination aperture, a lens, a computer, and a memory unit. The apparatus acquires an image by detecting a signal generated by irradiating a sample with a charged particle beam caused from the charged particle source via the off-axis illumination aperture. The computer has a beam-computing-process unit to estimate a beam profile of the charged particle beam and an image-sharpening-process unit to sharpen the image using the estimated beam profile.

The method is for automatic astigmatism correction of a lens system. A first image is provided that is not in focus at a first stigmator setting of a set of lenses. A calculating device calculates a corresponding first Fourier spectrum image. A distribution and direction of pixels of the Fourier spectrum image are determined by calculating a first vector and a second vector. The first vector is compared with the second vector. The lens system is changed from a first stigmator setting to a second stigmator setting to provide a second image. A corresponding Fourier spectrum image is calculated. The distribution and direction of pixels of the second Fourier spectrum image is determined by calculating a third vector and a fourth vector. The third vector is compared to the fourth vector. The image that has the lowest vector ratio is selected.

A charged particle beam apparatus includes: an electron source that irradiates a membrane-type holder with an electron beam; a deflector that changes an angle of incidence of the electron beam; a camera that is exposed to the electron beam transmitted through the membrane-type holder; and a control unit that controls the electron source, the deflector, and the camera. The control unit obtains an exposure image by continuously exposing the camera to the electron beam while changing the angle of incidence of the electron beam focused on any one of a first layer, a second layer, and a third layer included in the membrane-type holder.

The charged particle beam apparatus includes a charged particle source generating a charged particle beam, a deflector deflecting the charged particle beam, a detector detecting secondary electrons emitted from an irradiation target in response to irradiation with the charged particle beam, and a processor system. The processor system (A) acquires a first time-series change in secondary electron detection-related quantity by repeatedly performing the following (A1) and (A2), (A1) directly or indirectly, maintains or changes the control amount applied to the deflector to a first control amount, and (A2) acquires the secondary electron detection-related quantity based on an output from the detector, and (B) acquires a time-series change in variation of the beam diameter of the charged particle beam based on the first time-series change.

Systems, methods, and media for calibrating a scanning electron microscope (SEM). The system includes a processor and a memory. The memory stores instructions that, when executed by the processor, configure the system to perform operations. An electron microscope image of a periodic structure is generated by the SEM. A Fourier transform of the electron microscope image is computed to generate a spectrum. Reciprocal lattice vectors are computed based on a known periodicity of the periodic structure. A pixel mask is generated based on the reciprocal lattice vectors and applied to filter the spectrum. A quality metric is generated based on an aggregate magnitude of the filtered spectrum and a magnitude of a zero-frequency component of the filtered spectrum. A pixel scaling parameter, focus parameter, and/or stigmation parameter of the SEM are determined based on the quality metric.

A pitch walk inspection method includes obtaining a scanning electron microscope (SEM) image for a line and space (L/S) pattern formed by a multi-patterning technology (MPT), where L/S pattern includes a plurality of lines and spaces that are alternately arranged; detecting a main pitch of the L/S pattern in the SEM image; dividing a graph of the main pitch into graphs of component pitches, based on the MPT; performing a Fast Fourier Transform (FFT) on each graph of the component pitches; multiplying a phase and an intensity graph of the FFT of each of the graphs of the component pitches with each other and obtaining compensated FFT phase graphs; and calculating a pitch walk for the L/S pattern by obtaining differences between phase peak values of the compensated FFT phase graphs.

The present invention discloses an imaging method and an apparatus for direct electron detection cameras and a computer device, and relates to the technical field of electron microscope cameras. The present invention is mainly capable of improving the signal-to-noise ratio (SNR) of an image so as to improve the detective quantum efficiency of electron. The method includes the steps of classifying clusters in an original image to obtain low SNR clusters and high SNR clusters; performing three-dimensional reconstruction by using the images corresponding to the low SNR clusters and the high SNR clusters, respectively, to obtain three-dimensional models corresponding to the low SNR clusters and the high SNR clusters, respectively; performing filtering on the image corresponding to the low SNR clusters by using the filtering function, and superimposing the image to obtain m output image corresponding to the vitrified sample.