Gait Analysis for Identification of Perpetrators – Impact of Masking on Gait

Identification of perpetrators by means of closed-circuit TV (CCTV) increasingly gains in importance. In many crime scenarios, the perpetrator is masked, which could lead to limitations of the field of vision. This study aims at examining potential changes of forensically relevant gait parameters caused by masking. 12 persons in short clothes repeatedly walked along a 6 m walkway without masking and wearing a balaclava and full-face motorcycle helmet. Relevant joint angles were marked on skin and clothes, and the gait pattern was filmed at 50 Hz. Minimum and maximum knee and hip angles as well as the stride length were determined based on frames, and statistically compared between the tests situations. No significant differences were identified between the masking situations examined. With undisturbed movement, slight restrictions of the field of vision caused by masking did not result in a change of the angle parameters of the leg or the stride length and should therefore not necessarily affect the gait pattern quality required for forensic analysis.