The scientific comparison and analysis of the features that make up the face.
Facial Mapping is the study and comparison of the human face, and by using a variety of facial mapping techniques it is possible to determine whether two images show the same person.
We all have the ability to distinguish between two faces, but Facial Mapping takes this a stage further by scientifically studying the various features of the face and their interrelationships.
There are a number of Facial Mapping techniques that FVS use, these are:
- Measurement and Photography of the Face: Measurements are taken in order to compare with imagery from the offence.
- Morphological Comparison: The facial features are compared against scientifically-agreed descriptions. Unique features are also measured and described.
- Proportional Comparison: The proportions of the facial features and how they interrlate are measured and compared.
- Superimposition: Images from the same angles are scaled and placed over one another, and compared for differences in the shape of the face and facial features.
The graphics below show examples of proportional comparison, and descriptions of the morphological points of the nose:
As well as facial clues, FVS analysts use contextual information to identify people - this means the way they walk, their overall body shape, the way they hold their head, their stance, or how they gesture in conversation. We are also to examine height and build through body mapping and photogrammetry.
FVS analysts use the ACE-V (Analysis, Comparison, Evaluation, Verification) method to in order to make the comparison:
- Imagery is first Analysed for quality and usefulness, and the observed features are identified on both sets of imagery.
- The observed features are then Compared for similarities and differences.
- The strength of the similarities and differences are then Evaluated.
- The findings and conclusions are independently Verified by other trained analysts through a process of rigorous peer review.