Table 1.

Average correlation coefficient of projection vector p and diaphragm positions for various methods for retrospective evaluation

Methods	Monoplane	Biplane
	(mean $\pm$ std)	(mean $\pm$ std)
Vessel Removed	0.9490 $\pm$ 0.0446	0.9529 $\pm$ 0.0424
Downsampled Image	0.9330 $\pm$ 0.0754	0.9357 $\pm$ 0.0742
With Mask	0.8637 $\pm$ 0.1883	0.8552 $\pm$ 0.2503
Inverted Mask	0.9032 $\pm$ 0.1156	0.9007 $\pm$ 0.1197