Human Identification at a Distance (HID)

Objective

Human identification from facial features has been studied primarily using imagery from visible video cameras. Thermal imaging sensors are one of the most innovative emerging techonologies in the market. Fueled by ever lowering costs and improved sensitivity and resolution, our sensors provide exciting new oportunities for biometric identification. As part of our involvement in this effort, Equinox is collecting an extensive database of face imagery in the following modalities: coregistered broadband-visible/LWIR (8-12 microns), MWIR (3-5 microns), SWIR (0.9-1.7 microns). This data collection is made available on this Web Site for experimentation and statistical performance evaluations. During Phase I, initial performance evaluations will be made to assess the utility of thermal infrared images for face recognition, detection and tracking.

Approach

The gray value response of a thermal sensor depends on the temperature and emisivity of the target, as well as intrinsic properties of the focal plane array. In order to translate such responses into invariant physical flux measurements, it is necessary to calibrate the sensor with respect to a black body source. This allows us to compare data aquired under various conditions with respect to a single standard. With this in mind, it is important to establish formal protocols for collection of thermal infrared imagery.

A key problem for face recognition from visible imagery has been accurate identification under variable illumination conditions. The visible light impigent on a camera sensor is a product of the reflectivity of the subject's skin and the light incident on thereon. Therefore, it is impossible to separate intrinsic properties of the subject from those of the ambiant illumination conditions. On the other hand, thermal emission from skin is an intrinsic property, independent of illumination. In order to better exploit this invariance for face recognition, Equinox is conducting thorough data collections and evaluation efforts. Validation trials are being conducted to compare recognition performance of visible and thermal imagery.

In support of these trials, a coregistered visible/LWIR camera sensor is being used to collect image pairs under identical conditions. Additionally, boresighted SWIR and MWIR imagery is being aquired. This allows us to test algorithm performance under controlled conditions.