Novel DORT Method in Non-Well-Resolved Scatterer Case

The decomposition of time reversal operator (DORT) method is an efficient technique to select focusing signal on the target in well-resolved scatterer case. The DORT method requires the measurement of the inter-element impulse responses and diagonalizes these responses to find eigenstructure of the medium. However, the DORT method is not able to produce satisfactory result for non-well-resolved scatterer case (i.e., two scatterers that are placed closely about 0.2lambda). Therefore, in this letter, a weighted least squares (WLS) algorithm is introduced in the DORT method to perform selective focusing in non-well-resolved scatterer case. This technique called the WLS-DORT method performs better spatial focusing resolution than the conventional DORT method and results in simpler computational complexity than the minimum variance beamforming method under practical implementation.