Abstract: Filter holder (10) having a tubular overall shape and made of an elastic material, an annular groove (40) being formed on the interior surface of the filter holder.

Abstract: A lighting device for increasing the contrast of an image of a concave or convex structure provided on a surface, the device including: a first light source arranged so as to emit, according to a first axis of incidence Ii, a first light, the bandwidth of said first light, or “first bandwidth”, being less than 100 nm; a second light source arranged so as to emit, according to a second axis of incidence, a second light, the bandwidth of said second light, or “second bandwidth”, being less than 100 nm; and a third light source arranged so as to emit, according to a third axis of incidence, a third light, the bandwidth of said third light, or “third bandwidth”, being less than 100 nm, the first, second, and third axes of incidence being substantially convergent and the bandwidths of the first, second, and third lights being divergent from each other.

Abstract: A lighting device for increasing the contrast of an image of a concave or convex structure provided on a surface, the device including: a first light source arranged so as to emit, according to a first axis of incidence Ii, a first light, the bandwidth of said first light, or “first bandwidth”, being less than 100 nm; a second light source arranged so as to emit, according to a second axis of incidence, a second light, the bandwidth of said second light, or “second bandwidth”, being less than 100 nm; and a third light source arranged so as to emit, according to a third axis of incidence, a third light, the bandwidth of said third light, or “third bandwidth”, being less than 100 nm, the first, second, and third axes of incidence being substantially convergent and the bandwidths of the first, second, and third lights being divergent from each other.