Device for detecting a hot point in a scene by means of infrared radiation and missile guidance system equipped with such a device

A device for detecting a hot point in a scene by means of infrared radiation in an infrared wavelength band, said device comprising:

• a scanning system for scanning the radiation in the scene and generating a scanning beam therefrom;
• a radiation-sensitive detection system for converting the scanning beam into an electrical signal;
• and
• an electronic processing circuit for processing the electronic signal;
• characterized in that:
• the device further comprises a filter arranged in the path of the scanning beam, said filter splitting the scanning beam into first and second subbeams, the first subbeam containing radiation of a wavelength in a first subband of the wavelength band, the second subbeam contained radiation of a wavelength in a second subband of the wavelength band;
• the detection system comprises first and second radiation-sensitive detectors, the first detector converting radiation of a wavelength in the first subband into an electrical signal, the second detector converting radiation of a wavelength in the second subband into an electrical signal;
• and
• the electronic processing circuit comprises a subtractor circuit whose inputs are the outputs of the detectors, and whose output signal indicates the occurrence of a hot point.