Table 2.

SNR analyses of 2D images and 3D reconstructions of CETP before and after contrast enhancement.

Enhancement on the noisy images of simulated CETP images				Combination enhancement on the super high noisy images of simulated CETP
2D image		3D reconstruction		2D image			3D reconstruction
raw	enhanced	raw	enhanced	raw	lp8Å	lp8Å + enh	lp8Å	lp8Å + enh
0.80	1.33	0.61	0.94	0.25	1.57	2.28	3.96	4.89
0.50	0.83	0.38	0.61	0.20	1.25	1.76	3.15	3.88
0.30	0.49	0.24	0.37	0.15	0.93	1.26	2.39	2.90

The SNRs of the simulation of CETP. “2D” represents the untilt images, “3D” represents the 3D reconstruction, “raw” is for the initial image, and “enhanced” is for the image after contrast enhancement. “lp8Å” is for the images after low-pass filtered at 8 Å, and “lp8Å + enh.” is for the images after low-pass filtered at 8 Å and enhancement.