Foot measurements from three-dimensional scans: A comparison and evaluation of different methods

An approach to automatic foot measurement using 3D scanned data is proposed in this paper. The proposed approach was evaluated through comparisons of simulated measurements (SM) of eleven male and nine female participants with manual measurements (MM) and with the output of a commercially available automated foot measuring system (CP). The registration procedure for the measurements and unambiguous definitions for each measurement were first established. Eighteen dimensions of each foot were calculated from the scanned data that comprised point clouds and selected landmarks. Two operators manually measured each participant's foot twice. These MM showed high inter- and intra-operator reliability (ICC>0.84). Ten of the 18 dimensions obtained from the three measurement methods, SM, CP, and MM, were subjected to an ANOVA and eight of the measurements showed significant differences among the three methods. After establishing a linear correction to adjust for systematic errors, there were no significant differences between the SM and MM methods for 17 of the 18 foot dimensions; and the single exception was the heel width dimension. The differences among the three methods, correction procedures and their significance are discussed.Relevance to industryMeasuring feet to obtain the relevant dimensions that characterize feet can be quite tedious and the measurement may be dependent on the measurer. Automatic measurement with scanned data, on the other hand, can give replicable information even though the measurements depend on the intricacies of the scanning system and the computational algorithms adopted. The proposed definitions and algorithms provide a means to automate foot measurements for customized footwear.