There is provided a method of image acquisition capable of reducing the effects of diffraction contrast. This method of image acquisition is implemented in an electron microscope for generating electron microscope images with electrons transmitted through a sample. The method starts with obtaining the plural electron microscope images while causing relative variations in the direction of incidence of an electron beam with respect to the sample. An image is generated by accumulating the plural electron microscope images.

In some embodiments, a scientific instrument includes an electron-beam column configured to scan an electron beam across a sample. The electron-beam column includes a beam blanker configured to gate the electron beam in response to a drive signal. The scientific instrument also includes an electron detector configured to measure a flux of transmitted or scattered electrons having interacted with the sample and an electronic controller configured to acquire an image of the sample using values of the flux measured with the electron detector for a plurality of electron-beam scan locations. The electronic controller is further configured to cause the drive signal to have a gating frequency at which the image has a moir pattern therein.

A pattern inspection apparatus includes an actual outline image generation circuit to generate an actual outline image of a predetermined region defined by a function, where the gray scale value of each pixel in the predetermined region including plural actual image outline positions on an actual image outline of a figure pattern in an inspection image is dependent on a distance from the center of a pixel concerned to the closest actual image outline position in the plural actual image outline positions, and a reference outline image generation circuit to generate a reference outline image of the predetermined region defined by the function, where a gray scale value of each pixel in the predetermined region is dependent on a distance from the center of a pixel concerned to the closest reference outline position in plural reference outline positions on a reference outline to be compared with the actual image outline.