Device for non-invasive detection of predetermined biological structures associated with areas visible to the naked eye, provided with a) means for illuminating the area to be investigated by means of infrared light, adapted to be absorbed selectively by the biological structure to be investigated, and light with band in the visible field, b) means for splitting the light at the inlet to the cameras, into a light beam with light with spectral band relating to the infrared field and light beam with spectral band in the visible c) acquisition means of two images, one relating to the information content of the split light beam relating to the infrared field, and one relating to the information contribution of the light beam in the visible field, d) means for superimposing the two images to produce a single image that shows the area to be investigated as in the visible with superimposed the shape of the hidden structure to be investigated, e) a viewer for viewing said single image.
