Fig. 2.

(a) Resolution kernels of the upper-left source located at (0, −1, −6) cm. Five values of σ_c were used: σ_c = 0, σ_c = 0.05σ₁, σ_c = 0.1σ₁, σ_c = 0.2σ₁, and σ_c = 0.5σ₁. The SSNR, which is defined as $({\sigma }_1\Vert \mathit{f}\Vert )/({\sigma }_0\sqrt{M})$, was set to 2. (b) Plot of the peak value of the kernel, $ℝ({\mathit{r}}_1,{\mathit{r}}_1)=\sqrt{{\mathit{f}}^T{\mathit{D}}^{-1}\mathit{f}}$, with respect to σ_c for three SSNR values. (c) The same resolution kernels as shown in (a) in which each kernel is normalized with its peak value. (d) Plot of the FWHM of the resolution kernel with respect to σ_c for three SSNR values.