... 2.1
For very large objects the near field is not really near, since one must let the diffraction figures from various objects interfere. This leads to the additional condition $ D^* = \frac{\lambda }{d} z\gg \delta$, where $ \delta$ is the typical distance between scatterers. 
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... screen2.2
Experimental correlation functions shown in figure are calculated according to the following procedure. First, the Fast Fourier Transform of the intensity distribution is calculated. Then the result is squared. The auto-correlation is then obtained by anti-transforming the power spectrum. 
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... points3.1
Sets with odd number of points will give vanishing contributions if $ f\left(\vec{x}\right)$ has a vanishing mean value. 
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