Table 2.

The image contrasts and signal-to-noise ratios calculated for five spheres in reconstructed image of cold-sphere hot-background phantom with and without use of the filters

	None		Hann		Hamming		Cosine		Shepp-Logan		Ram-Lak
	Contrast	SNR	Contrast	SNR	Contrast	SNR	Contrast	SNR	Contrast	SNR	Contrast	SNR
Sphere 1	−10.21	13.29	−61.56	19.47	−62.26	18.46	−65.91	15.73	−68.88	9.84	−70.37	7.88
Sphere 2	−8.54	11.12	−50.28	15.91	−51.40	15.24	−56.38	13.45	−61.59	8.80	−64.27	7.20
Sphere 3	−6.22	8.10	−36.34	11.49	−37.65	11.16	−43.60	10.40	−49.63	7.09	−52.71	5.90
Sphere 4	−3.32	4.32	−10.97	3.47	−11.36	3.37	−13.62	3.25	−15.19	2.17	−15.96	1.78
Sphere 5	−2.13	2.78	−6.00	1.90	−6.88	2.04	−9.80	2.34	−14.53	2.07	−17.04	1.91

Sphere 6 isn’t recognizable. SNR: Signal-to-noise ratio