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1.2 A brief history 11

(a) (b) (c)

(d) (e) (f)

Figure 1.7 Some early (1970s) examples of computer vision algorithms: (a) line labeling (Nalwa 1993) c 1993
Addison-Wesley, (b) pictorial structures (Fischler and Elschlager 1973) c 1973 IEEE, (c) articulated body model
(Marr 1982) c 1982 David Marr, (d) intrinsic images (Barrow and Tenenbaum 1981) c 1973 IEEE, (e) stereo
correspondence (Marr 1982) c 1982 David Marr, (f) optical flow (Nagel and Enkelmann 1986) c 1986 IEEE.

(Roberts 1965). Several line labeling algorithms (Figure 1.7a) were developed at that time
(Huffman 1971; Clowes 1971; Waltz 1975; Rosenfeld, Hummel, and Zucker 1976; Kanade
1980). Nalwa (1993) gives a nice review of this area. The topic of edge detection was also
an active area of research; a nice survey of contemporaneous work can be found in (Davis
1975).
Three-dimensional modeling of non-polyhedral objects was also being studied (Baum-
gart 1974; Baker 1977). One popular approach used generalized cylinders, i.e., solids of
revolution and swept closed curves (Agin and Binford 1976; Nevatia and Binford 1977), of-
7
ten arranged into parts relationships (Hinton 1977; Marr 1982) (Figure 1.7c). Fischler and
Elschlager (1973) called such elastic arrangements of parts pictorial structures (Figure 1.7b).
This is currently one of the favored approaches being used in object recognition (see Sec-
tion 14.4 and Felzenszwalb and Huttenlocher 2005).
A qualitative approach to understanding intensities and shading variations and explaining
them by the effects of image formation phenomena, such as surface orientation and shadows,
was championed by Barrow and Tenenbaum (1981) in their paper on intrinsic images (Fig-
ure 1.7d), along with the related 2 / 2 -D sketch ideas of Marr (1982). This approach is again
1
seeing a bit of a revival in the work of Tappen, Freeman, and Adelson (2005).
More quantitative approaches to computer vision were also developed at the time, in-
cluding the first of many feature-based stereo correspondence algorithms (Figure 1.7e) (Dev
1974; Marr and Poggio 1976; Moravec 1977; Marr and Poggio 1979; Mayhew and Frisby
1981; Baker 1982; Barnard and Fischler 1982; Ohta and Kanade 1985; Grimson 1985; Pol-
lard, Mayhew, and Frisby 1985; Prazdny 1985) and intensity-based optical flow algorithms

7 In robotics and computer animation, these linked-part graphs are often called kinematic chains.