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 between, on the one hand, the first values and, on the other hand, second values representative of the temperatures that the bolometric membranes of said neighboring pixels would have according to a theoretical model if the temperature and the emissivity of the scene element had the estimated values.