A method used to determine the probable population accommodation of a helmet sizing system is described. The method involves the use of 3D laser scanning, as a means of measuring helmet stand-off distance (distance between the inside of the helmet and the skull), and the selection of a representative sample of test subjects. The laser scanner and the software developed to calculate stand-off distance proved to be an excellent tool for the assessment of helmet fit. The main advantages include ease of use and visualisation of problem areas. This 3D-analysis method gives designers objective evidence of the need for design changes as well as an idea of what these changes should be. A comparison was made between stand-off distance results obtained from the scanner and those obtained using a physical measurement method (a probe). Although discrepancies were found between the two, sources of errors intrinsic to both methods make it difficult to determine which of the two methods yielded the truest stand-off distance. Analysis of the comparison data shows laser scanning to be slightly more conservative than the probe method for stand-off distance purposes, ie erring on the side of safety. (A)
Samenvatting