Harald Westphal Hans-Hellmut Nagel Toward the derivation of three-dimensional descriptions from image sequences for nonconvex moving objects. 302-320 1986 34 Comput. Vis. Graph. Image Process. 3 https://doi.org/10.1016/S0734-189X(86)80045-7 db/journals/cvgip/cvgip34.html#WestphalN86