Devising MIMO arrays for underwater 3-D short-range imaging

To reduce the sensor number and restrict the array size of an underwater 3-D imaging system, the multiple-input multiple-output (MIMO) array is adopted in this paper. The relationship between the narrowband or wideband MIMO array and its virtual array is discussed in detail and the analytical solution of the coordinates of the virtual sensors is given. Based on the ability of providing virtual sensors of MIMO arrays, several MIMO array layouts are proposed, which can be equivalent to the rectangular planar array, the cylindrical array and the spherical array, respectively. And plenty of sensors in these array layouts are saved. Moreover, some MIMO arrays which can reduce the sensor number and the array size simultaneously are also introduced.