CCTV footage serves as a useful tool for testing eyewitness ability is a mock footage of an illegal event. Additionally, eyewitness testimony ability can be tested by having participants view a mock theft then asking them to pick the perpetrator out of a lineup of mugshots. CCTV footage provides contextual stimuli for testing eye-witness ability that is different to standardized mugshots.
Body-recognition software has the advantage of being able to identify a person where their face might not be visible. The recording of a 360 degree video of a suspect’s body serves to test the software’s effectiveness.
What did we collect?
We collected CCTV footage from predetermined CCTV choke points. Choke points refer to locations, such as doorways or hallways, where people must move through them in a typical fashion with their faces visible. CCTV cameras are typically installed at these choke points. Replicating a representative choke point provides useful stimuli for testing face-detection software.
Additionally, we recorded participants pretending to steal an item from an empty drawer at the back of the room. For a realistic theft it is important that the experimenter is not in the room while the theft is recorded. We start the cameras recording and escort the participant’s outside. Then we instruct the participant to walk back into the room, open the drawer, steal the item, and then walk back outside. We also collected a 360 degree video of a person’s body.
How did we collect it?
For the CCTV footage, we selected one choke point in our test lab and installed two cameras on either side of the choke point (one direct and one at 45 degree angle). We record participants separately walking up and down the length of the test room, so that for each camera we have the participant walking towards the camera and away from the camera.
The mock theft uses the same camera setup described in the CCTV choke point method.
In order to obtain a 360 degree video, we asked participants stand in front of the Avigilon CCTV camera and were instructed to spin on the spot. Specifically, participants were asked to spin around on the spot, making the spin last approximately 10 seconds, and to keep their eyes focused on an imaginary horizon.