Numerical results The 20th trace before and after beamforming Beamforming for level 2 Original noisy data 0.05 -0.05 -0.2 -0.25 100 600 700800 9001000 A Direct Numerical Imaging Method 36 National University of Defense TechnologyA Direct Numerical Imaging Method Numerical results 36 Beamformed for level 2. 0 100 200 300 400 500 600 700 800 900 1000 -0.25 -0.2 -0.15 -0.1 -0.05 0 0.05 0.1 0.15 0.2 0.25 The 20th trace before and after beamforming. Denoised data before beamforming Beamforming for level 2 Original noisy data