title: A comparison of three-dimensional and two-dimensional analyses of facial motion.
abstract: The purpose of this study was to compare the amplitude of facial motion obtained using three-dimensional (3-D) and two-dimensional (2-D) methods. The amplitude of motion of fifteen facial landmarks during five maximal animations (smile, lip-purse, grimace, eye closure, and cheek-puff) was quantified in 3-D and 2-D using a video-based system. Results showed that the 3-D amplitudes were significantly larger than the 2-D amplitudes, especially for landmarks on the lower face during the smile animation. In the latter instance, the 2-D amplitudes underestimated the 3-D amplitudes by as much as 43%. The difference between 3-D and 2-D amplitudes was greater for 2-D amplitudes obtained from one camera rather than from multiple cameras. The results suggest that a 2-D analysis may not be adequate to assess facial motion during maximal animations, and that a 3-D analysis may be more appropriate for detecting clinical differences in facial function.
authors.affiliation: Department of Movement Science, University of Michigan, Ann Arbor 48109-2214, USA.
authors.forename: M M
authors.initials: MM
authors.lastname: Gross
authors.forename: C A
authors.initials: CA
authors.lastname: Trotman
authors.forename: K S
authors.initials: KS
authors.lastname: Moffatt
mesh_terms: D000328:Adult; D002508:Cephalometry / Q000379:methods*; D002648:Child; D002972:Cleft Palate / Q000503:physiopathology; D005145:Face / Q000502:physiology*; D005149:Facial Expression; D005152:Facial Muscles / Q000502:physiology; D006801:Humans; D009068:Movement; D010780:Photogrammetry; D012016:Reference Values; D014741:Video Recording / Q000295:instrumentation / Q000379:methods