Researchers from the Changchun Institute of Optics, Fine Mechanics and Physics of the Chinese Academy of Sciences have developed an optical system that focuses light from several subfields onto a single small-format detector. By analyzing field-dependent spot shapes, the system identifies which subfield an isolated infrared target comes from. In sequence-level tests, it identified the correct field in about 89% of cases. The study is published in Optics and Laser Technology.