“…A rule-based scheme is a sequence of steps, tests and rules. Most algorithms for the segmentation of lung fields fall in this category [198,269,270,65,4,6,7,32,82,84]. Techniques employed are (local) thresholding, region growing, edge detection, ridge detection, morphologi-RB PC PA / lateral evaluation remarks Toriwaki [233,232] × PA none describes a complete analysis system Harlow [102] × PA none Chien [37,38] × PA none only right lung, result used to detect abnormalities Hasegawa [103] × PA none Pietka [198] × PA none McNitt-Gray [179,178] × PA 16 Q uses 5 anatomical classes Duryea [65] × PA 802 Q Xu [269] × PA 1000 R outer rib cage only Xu [270] × PA 300 R diaphragm edges only Armato [7] × PA 600 R costophrenic angles only Armato [4] × lateral 200 Q Armato [6] × PA 600 R Carrascal [32] × both 65 RQ Vittitoe [250] × PA 99 Q Tsujii [235] × PA 71 Q Wilson, Brown [265,28] × PA none describes a complete analysis system Vittitoe [251] × PA 115 Q uses 6 anatomical classes Van Ginneken [82,84] (Chapter 3)…”