Plane wave imaging combined with eigenspace-based minimum variance beamforming using a ring array in ultrasound computed tomography

Table 1 Parameters in simulations and experiments

Parameter	Computer simulation	Phantom experiment	Parameter	Computer simulation	Phantom experiment
$N$	540	512	$f_{s}$	10 MHz	20 MHz
pitch	1.15 mm		Excitation signal	Sine (2 cycles)	Square (2 cycles)
kerf	0.2 mm		$N^{\prime}$	32, 64,…
$R$	99 mm		$L$	$N^{\prime}/4$
$\Delta \theta$	0.67°		Diagonal loading	${\raise0.7ex\hbox{$1$} \!\mathord{\left/ {\vphantom {1 {100 L}}}\right.\kern-0pt} \!\lower0.7ex\hbox{${100 L}$}}$
$M$	68	58/50	Eigenvalue (signal)	$\lambda_{i} > 0.05*\lambda_{max}$
$f_{c}$	1 MHz		Eigenvalue (noise)	$\lambda_{i} < 0.05*\lambda_{max}$

ISSN: 1475-925X

Parameter	Computer simulation	Phantom experiment	Parameter	Computer simulation	Phantom experiment
\(N\)	540	512	\(f_{s}\)	10 MHz	20 MHz
pitch	1.15 mm		Excitation signal	Sine (2 cycles)	Square (2 cycles)
kerf	0.2 mm		\(N^{\prime}\)	32, 64,…
\(R\)	99 mm		\(L\)	\(N^{\prime}/4\)
\(\Delta \theta\)	0.67°		Diagonal loading	\({\raise0.7ex\hbox{$1$} \!\mathord{\left/ {\vphantom {1 {100 L}}}\right.\kern-0pt} \!\lower0.7ex\hbox{${100 L}$}}\)
\(M\)	68	58/50	Eigenvalue (signal)	\(\lambda_{i} > 0.05*\lambda_{max}\)
\(f_{c}\)	1 MHz		Eigenvalue (noise)	\(\lambda_{i} < 0.05*\lambda_{max}\)