Near field imaging algorithm of the large target by considering roundtrip propagation loss

The roundtrip propagation loss of spherical wave is remarkable for the near-field imaging of large and complicated targets. The spherical back-projection (SBP) algorithm was modified by introducing a compensation factor for the roundtrip propagation loss. The magnitude precision of the image is increased by the modified algorithm. In the same sense, the spherical convolution back-projection (SCBP) algorithm was also modified. Comparisons of the numerical simulating between the modified SBP and the modified SCBP indicate that the precisions of the two algorithms are almost the same but the computation cost of the modified SBP is reduced.