Table 2 Important parameters for simulated and experimental for acquisition and data processing

Central, sampling frequencies (MHz)

6.25, 25

6.25, 40

Transducer model

L11-4v

L11-4v

Number of elements (NE)

128

128

NE for emission, reception

128, 128

128, 128

Subarray length (L)

64

64

Sound speed (m/s)

1540

1540

Fractional bandwidth (%)

60

60

Pitch (mm)

0.3

0.3

F number

1.75

1.75

Range, angles, gap

\(-5^{\circ }\) to \(5^{\circ }\), 21, \(0.5^{\circ }\)

\(-5^{\circ }\) to \(5^{\circ }\), 21, \(0.5^{\circ }\)

Data acquiring

From field II

CRP (ATS)

Diagonal loading

\(\Delta =0.01\)

\(\Delta =0.01\)

Subspace construction

\(\alpha _{\text {th}}=0.05\)

\(\alpha _{\text {th}}=0.05\)

SNR-CF weight param

\(\alpha _\text {snr}=\pi\), \(\beta _\text {snr}=0.5\)

\(\alpha _\text {snr}=\pi\), \(\beta _\text {snr}=0.5\)