THE USE OF ARCH INDEX TO CHARACTERIZE ARCH HEIGHT - A DIGITAL IMAGE-PROCESSING APPROACH

Attempts to evaluate foot arch types from footprint parameters have yi elded conflicting results in the past. This could be caused by the unc ertainty inherent in the definition of some footprint parameters and t he inaccuracy during the footprint acquisition and the parameter calcu lation phases of the traditional methods. In order to avoid these prob lems, digital image processing methods were used to acquire and to cal culate the Arch Index (AI), a parameter which is robust in its definit ion. A significant correlation (r = -0,70, p < 0.0001) was found betwe en AI and arch height. Therefore this study confirms that foot arch ty pe does correlate with the Footprint parameter, AI. This was further r evealed by a new parameter, the Modified Arch Index (MAI), which incor porates foot pressure information in the evaluation, MAI not only corr elated well with arch height (r = -0.71, p < 0.0001) but appeared to c haracterize abnormal foot types better than AI.