Table 2.

Summary of the rule-based algorithms for noise removal

Steps	Location	Area
To remove small connected pixel	Anywhere	< 0.005 of image size
To eliminate clavicle	Near to top: (0 < pixel < 0.35 of r 0) and (minimum row ≤ 0.2 of r 0)	≥ 0.15 of c 0
	Right lung: Top-right (0 < pixel < 0.5 of c 0) and (minimum column ≤ 0.25 of c 0)
	Left lung: Top-left (0.5 of c 0 < pixel < c 0) and (maximum column ≥ 0.75 of c 0)
To eliminate sides’ artefacts	(region ≤ 0.15 of c 0)
	Right side: (minimum column ≤ 0.05 of c 0)
	Left side: (maximum column ≥ 0.85 of c 0)
To eliminate body artefacts	Near the bottom image’s margins: (minimum row ≥ 0.25 of r 0) and (maximum row ≥ 0.9 of r 0)	≥ 0.25 of image size
	Right side: (minimum column ≤ 0.05 of c 0)
	Left side: (maximum column ≥ 0.95 of c 0)
To eliminate small region after lung outline is formed	Right side: (maximum column < 0.2 of c 0)	≤ 0.15 of A max
	Left side: (minimum column > 0.8 of c 0)