Face verification robustness & camera-subject distance

After the international standardisation working group responsible for machine-readable travel documents (ISO/IEC JTC1/SC17/WG3) raised the question whether magnification distortion of facial images affected the accuracy of facial recognition, a study was conducted to determine to which degree the algorithms used for face comparison are affected. This study was described in a previous issue of Keesing's Journal of Documents and Identity.[1] It involved photographing several hundreds of enrolees at various distances (0.5 m to 3 m) with an automatic bench. One of the working group's findings discussed in this article is that magnification distortion of facial images due to pictures taken too close up does negatively affect facial recognition. However, for distances over 0.5 m the effect is very limited.