1. Image acquisition device comprising: a photocathode, configured to convert an incident flux of photons into a flux of electrons; a sensor composed of a matrix of elements named pixels; and a processor; wherein: the device comprises a matrix of elementary filters, each associated with at least one pixel of the sensor, said matrix being located upstream from the photocathode, such that an initial flux of photons passes through said matrix before reaching the photocathode; the matrix comprises primary color filters (R, G, B; Ye, Ma, Cy), a primary color filter not transmitting a part of the visible spectrum complementary to said primary color, and filters transmitting the entire visible spectrum, named panchromatic filters; and the processor is configured to: calculate a quantity, termed a useful quantity, for determining whether at least one zone of the sensor is under conditions of weak or strong illumination, the useful quantity being representative of a mean surface flux of photons or electrons detected on a set of pixels named panchromatic pixels of the sensor, each panchromatic pixel being associated with a panchromatic filter; and forming, only if said zone is under conditions of strong illumination, a color image of said zone on the basis of the pixels in this zone associated with primary color pixels.