The main purpose of the tutorial is a consistent presentation of the theoretical foundations of passive optoelectronic devices, that is, devices that perceive either their own radiation of objects and backgrounds, or the radiation of natural sources reflected by them. The main sections of the book are scanning, raster modulation of radiation, extraction of an optical signal against a background of random interference. Issues of perception and analysis of images are considered. A separate section is devoted to thermal imaging and iconics.