2. Direct imaging for point targets : the signal space SVD vs=spanu,u, L, u,i dVN. the noise space The imaging function (x l p. cf al-a kox)? i P k=1 (過两科学大季 A Direct Numerical Imaging Method National University of Defense TechnologyA Direct Numerical Imaging Method 2. Direct imaging for point targets 9 P( ) w The imaging function V S : the signal space SVD V N: the noise space 2 2 2 2 1 1 1 ( ) ( ) ( ) S ( ) ( ) N V k k I x g P g g g u = = = - - ? å v v v v v x x x x 1 2 { , , , } S N V span = v v v u u u L