Implementing holistic dimensions for a facial composite system

Abstract

Facial composites are pictures of human faces. These are normally constructed by victims and witnesses of crime who describe a suspect's face and then select individual facial features. Unfortunately, research has shown that composites constructed in this way are not often recognised. In contrast, we are quite good at recognizing complete faces, even if the face was unfamiliar and only seen briefly, and this more natural way of processing faces is at the heart of a new composite system called EvoFIT. With this computer program, witnesses are presented with sets of complete faces for selection and a composite is ‘evolved' over time. The current work augments EvoFIT by developing a set of psychologically useful scales - such as facial weight, masculinity, and age - that allow EvoFIT faces to be manipulated. These holistic dimensions were implemented by increasing the size and variability of the underlying face model and by obtaining perceptual ratings so that the space could be suitably vectorised. The result of three evaluations suggested that the new dimensions were operating appropriately.