While trolling through the net found following snippet
"A study by the government's National Institute of Standards and Technology (NIST), for example, found false-negative rates for face-recognition verification of 43 percent using photos of subjects taken just 18 months earlier, for example. And those photos were taken in perfect conditions, significant because facial recognition software is terrible at handling changes in lighting or camera angle or images with busy backgrounds. The NIST study also found that a change of 45 degrees in the camera angle rendered the software useless. The technology works best under tightly controlled conditions, when the subject is starting directly into the camera under bright lights - although another study by the Department of Defense found high error rates even in those ideal conditions. Grainy, dated video surveillance photographs of the type likely to be on file for suspected terrorists would be of very little use.
That is a bit discouraging but I persevere :-)
Any help from the larger collective would be appreciated.