Three-dimensional image reconstruction method, image processor, and transmission electron microscope, using image obtained by tilted electron beam conditions

An image processor for constructing a three-dimensional structure of membrane proteins, comprising:

• a first image acquisition portion for obtaining, with a field of view, a first transmission electron microscope image of a sample containing said membrane proteins present within a lipid membrane, the image having been taken by illuminating an electron beam on the sample from a direction tilted relative to a line normal to a membrane surface of the lipid membrane;
• a second image acquisition portion for obtaining, with a field of view that at least partially overlaps the field of view used to acquire the first transmission electron microscope image, a second transmission electron microscope image of the sample, the second transmission electron microscope image having been taken by illuminating the electron beam on the sample perpendicularly to the membrane surface of the lipid membrane;
• an orientation identification portion for identifying orientations of a plurality of particles of the membrane proteins in the first transmission electron microscope image on a basis of a rotational angle of the plurality of particles relative to an axis perpendicular to the lipid membrane of the corresponding plurality of particles of the membrane proteins in the second transmission electron microscope image;
• and
• a 3D image constructing portion for reconstructing a three-dimensional structure of the membrane proteins by:
• extracting a plurality of particle images of the membrane proteins from the first transmission electron microscope image,
• classifying the extracted images according to the orientation of the plurality of particles of the membrane proteins identified by the orientation identification portion,
• averaging the classified particle images for each of a plurality of orientations of the membrane proteins, and
• generating, based on the average of each classified particle image, a three-dimensional image of the membrane proteins.