Gait Recognition
Gait - how you walk - is a biometric that can be perceived at low resolution when other biometrics are not available. It is very suited to surveillance. Everyone has a unique pattern to their walk.
The pattern of your gait appears in shape of your silhouette as it changes when you walk. it doesn't matter whether your silhouette is seen from the side, front or back, or even from the top. it is unique to you.
Your gait is also recognizable from your footsteps -- how close they are together, the force from the various parts of your feet on the ground. Even the wear and tear on your shoes is a signature of how you walk. All of these things can be used to identify you from a distance.
People have a small but significant ability to identify people they know from a distance by the way they walk. Now machines can do it too. Collection of data about how you walk can be done in public, with simple instruments, and without your cooperation or even your awareness that you are being observed.
The ability to use gait recognition to identify you may not work very well under the following conditions:
- Footwear: You gait will change considerably with the type of footwear you have. Sandles, flats, court shoes, running shoes, formal shoes, high heels, hiking boots. An individual who frequently wore different types of shoes would be hard to recognize simply by their gait.
- Terrain: Your gate changes as you walk up or down hill, along a slope, over smooth or rough surfaces.
- Fatigue and Injury: If your body is not performing as usual because you are tired or injured, it will compensate. One of the ways it does this is by altering your gate.
- Energy and Athleticism: A brisk walk with "high energy", if that is not typical for you, will completely disrupt recognition.
- Walking with a cane or hiking stick: This confuses the matching of your moving silhouette to the bio-mechanical model that represents the way you walk -- your gait signature. Not only is there more in the image, but your arms and legs move differently.
- Carrying something: A person carrying something in the hands, or on their back, or even concealed under their clothing will have a gait signature significantly different their normal gait and from others who are without such a burden. This is often what authorities are looking for -- not a specific person but someone who is walking a bit unusually, perhaps because they are wearing a suicide vest.