§4), and the different observing modes: speckle imaging, aperture synthesis with pupil masks, speckle spectroscopy, and coronagraphy. The analysis of the wavefront is not yet implemented.

For speckle imaging, a few observers have independently reached the conclusion that “the bispectrum combined with a constrained iterative deconvolution of amplitudes produces the highest quality imagery” (Beletic and Goody, 1992). Nevertheless, we have used various programs ranging from Knox-Tompson (1974) to full bispectrum methods (Weigelt, 1977, Roddier, 1986, Lannes, 1989) (and even partial bispectrum methods, i.e. using only a subset of all possible closure relations) and found little differences on the restored phasor image of double stars. The pre-processing of the original data (correction of geometric distortion, of flat-field, and various calibrations) is for us the crucial step in the whole image restoration process.

The “Aperture Synthesis” team at OMP has been mainly involved during the last few years in the theoretical aspects of aperture synthesis and related problems such as deconvolution, wavelets and multi-resolution methods, with applications on single aperture interferometry and multi-aperture devices (Lannes [*et al.*]{} 1987; Lannes 1988, 1989, 1991). The approach to these problems is deterministic and based on a least-squares scheme that allows error analysis, hence a good 