Abstract: In this work we propose and implement an algorithm for identifying field-emission images with the aim of determining the crystallographic orientation of an emitter and obtaining detailed information about the structural features of its surface. A threshold-type analysis of the brightness distribution in the image is found to be preferable for selecting information-containing areas and their contours. An original algorithm is proposed for selecting the mask of a “spot” of arbitrary shape. The proposed algorithm of processing the information area is also applicable to “skeletons”; however, the contour of an information fragment should not contain more than one gap. In contrast to the skeletons, the use of internal areas of emission “spots” by means of determining geometric moments improves the reliability of processing results due to an increase in sampled information.