TABLE 4.

Qualitative categorization of all US images as evaluated by an expert radiologist. The US images were collected from the phantom. Experiments are divided by cases; case 1: using CT data without force feedback; case 2: using CT data with force feedback; case 3: using landmark prediction only without force feedback; case 4: using landmark prediction only with force feedback.

	Completely obstructed	Partially obstructed	Unobstructed	Visible center
Case 1	6	3	15	18
Case 2	0	4	20	24
Case 3	10	1	13	14
Case 4	3	3	16	19