Infrared image sensor

An infrared image sensor comprising:

• on a support, a plurality of first pixels and a plurality of second pixels intended to detect an infrared radiation emitted by an element of a scene, each pixel comprising a bolometric membrane suspended above a reflector covering the support, the reflector of each first pixel being covered with a first dielectric layer, and the reflector of each second pixel being covered with a second dielectric layer differing from the first dielectric layer by its optical properties;
• a circuit for reading out first values representative of the temperatures of the bolometric membranes of first and second neighboring pixels;
• and
• a processing unit capable of determining the emissivity of the scene element based on the first values, the processing unit being configured to generate estimated temperature and emissivity values corresponding to a minimum of an error value representative of differences, the differences comprising:
• a first difference between the first value read from the first pixel and a second value representative of the temperature that the bolometric membrane of said first pixel would have according to a theoretical model if the temperature and the emissivity of the scene element had the estimated values;
• and
• a second difference between the first value read from the second pixel and a further second value representative of the temperature that the bolometric membrane of said second pixel would have according to the theoretical model if the temperature and the emissivity of the scene element had the estimated values.