Image acquisition method and electron microscope

An electron microscope for scanning a sample with an electron probe and acquiring a scanned image, said electron microscope comprising:

• an electron source emitting an electron beam;
• an illumination lens system for focusing the emitted electron beam into said electron probe;
• a deflector for deflecting the electron beam to scan the sample with the electron probe;
• and
• a controller performing processing to acquire the scanned image;
• wherein the controller is configured to perform the steps of:
• raster scanning a region of the sample under observation with the electron probe by deflecting the electron beam with the deflector to thereby obtain a first scanned image;
• raster scanning the region under observation with the electron probe by deflecting the electron beam with the deflector to thereby obtain a second scanned image;
• and superimposing the first and second scanned images over each other;
• wherein, in the step of obtaining the first scanned image, each one of the scan lines is drawn with the electron probe in a first direction and then moved in a second direction perpendicular to the first direction;
• and
• wherein, in the step of obtaining the second scanned image, each one of the scan lines is drawn with the electron probe in the first direction and then moved in a third direction opposite to the second direction.