FDK-Type Algorithms with No Backprojection Weight for Circular and Helical Scan CT

Table 1

Variance of the noisy images in Figure 13 based on the noise-free images in Figure 7.

Algorithm	value×10^−4
FDK	1.3986
Hu’s	1.3999
T-FDK	0.27443
CFDKW-1	0.24365
CFDKW-2	0.26443
Zhu et al.’s	1.3999
EM-1	0.24365
EM-2	0.26443