  An extension may be proposed to the intensity interferometer of Hanbury Brown
and Twiss to provide the Fourier phase measurement by the use of third-order
intensity correlations. It is well known that interferometric reconstruction of
astronomical images can be obtained from second-order correlations only when a
priory information is used about the object. The third-order intensity
correlations contain information about the Fourier phase and need no such
assumptions. In the ordinary way we can make measurements of the second-order
intensity correlations with an intensity interferometer. We can also calculate
the third-order intensity correlations from the data set of measured
intensities for each distance triplet. After that we can reconstruct the
Fourier phase from third-order correlations by using bipectral technique. When
this is combining with the Fourier magnitude obtained from the second-order
intensity correlations, we have the ultimate Fourier transform of the source
brightness distribution. An inverse Fourier transform recovers the source
image.
