Noise Estimation for Single-Slice Sinogram of Low-Dose X-Ray Computed Tomography Using Homogenous Patch

Table 1

Variance analysis to estimate the noise level.

	Figure 2(c)						Figure 2(d)
Real SD	5		10		15		5		10		15
NO.	ESD	Diff	ESD	Diff	ESD	Diff	ESD	Diff	ESD	Diff	ESD	Diff
21	4.93	0.26	9.82	1.07	14.67	0.61	4.95	0.52	9.65	−0.26	14.42	3.75
22	4.94	0.10	9.86	0.78	14.78	3.00	4.96	0.15	9.69	0.90	14.45	0.95
23	4.91	−0.29	9.82	−0.79	14.74	−0.98	4.98	0.19	9.75	1.20	14.50	1.53
24	4.88	−0.29	9.75	−1.42	14.62	−3.48	4.98	0.19	9.75	1.20	14.52	0.34
25	4.90	0.22	9.81	1.19	14.71	2.63	5.13	0.80	9.82	0.53	14.68	4.80
26	6.61	19.68	10.76	19.64	15.34	18.71	5.20	0.69	9.94	2.42	14.77	2.42
27							5.25	0.51	10.02	1.52	14.87	3.17
28							5.30	0.54	10.04	0.42	14.89	0.53
29							5.94	7.24	10.35	6.17	14.98	2.73
30											15.32	10.38