A number of large retailers have implemented surveillance systems that record and interpret customer eye movement and facial expression, using software from Almaden’s BlueEyes research project.

BlueEyes works by tracking pupil, eyebrow and mouth movement, using a camera and two infrared light sources placed inside the product display. One light source is aligned with the camera’s focus; the other is slightly off axis. When the eye looks into the camera-aligned light, the pupil appears bright to the sensor, and the software registers the customer’s attention.

The stated purpose: anticipate customer wants, but the ACLU warns it may be used to gather identities and cross-reference income and buying preferences.