Recombining light of the VLTI at 10 microns by densifying the images

APreS-MIDI (APerture Synthesis in the MID-Infrared) instrument function is to recombine 4 telescope beams of the VLTI. Interference fringes are sampled in the pupil plane. The optical principle uses "image densification". It is perfectly adapted for reconstructing images by aperture synthesis at 10mm. This principle could be used for building a new generation 10mm instrument, but instead of making a totally new instrument, we propose the design of an optical module that can supply the current MIDI-VLTI instrument with 4 beams.