The SenseCam (commercially available as the Vicon Revue) is worn on a lanyard around the neck. It shoots and stores about three images a minute, and can run for about 12 hours on one battery charge. Users can view the photos later, as a means of reliving their day. Although it may sound a bit narcissistic, the camera is actually designed as a therapeutic device, to help people who have memory problems.
In a study conducted for the British Heart Foundation Health Promotion Research Group, 40 test subjects wore the cameras for three to five days, as they went about their everyday activities (it’s possible to suspend the SenseCam’s picture-snapping while doing things such as going to the bathroom). They also all wore an accelerometer, as would be found in activity-monitoring devices – the SenseCam contains an accelerometer of its own, along with other sensors, incidentally.
When the data was analyzed, it was noted that the separate accelerometer often couldn’t differentiate between sedentary sitting activities (such as watching TV) and healthier standing activities, as revealed by time-matched SenseCam photos. Overall, it was found that there was a discrepancy of about 30 minutes per day, when it came to sedentary activity as estimated by the accelerometer and as photographed by the SenseCam.
In another study, led by Gillian O’Loughlin of Ireland’s Dublin City University, a group of 47 football players, jockeys and physically-active college students wore the cameras while keeping track of their dietary intake through self-reporting for one day. The photos revealed that the subjects misreported things like portion size, types of food not eaten, brand names, and – importantly – they underestimated the number of calories consumed.
Papers on the studies, titled Using the SenseCam to Improve Classifications of Sedentary Behavior in Free-Living Settings and Using a Wearable Camera to Increase the Accuracy of Dietary Analysis, can be accessed via the link below.