Abstract: Disclosed is an image detector of the type comprising an array of photosensitive dots and an additional light source. The disclosed device can be applied to particular advantage in the detection of radiological images. The image detector comprises a photosensitive matrix and an additional source positioned on opposite faces of a support. The matrix is exposed to a radiation known as an incident radiation, a part of which is not detected by the matrix. The detector furthermore comprises means to promote the transmission of an additional radiation produced by the additional source with respect to the undetected part of the incident radiation. An arrangement of this kind enables an improvement in the contrast of the image, especially at the low spatial frequencies.