Monitor and Control -
From this level of detail, an observer should be able to monitor the number, direction and speed of movement of people, providing their presence is known to him; i.e. they do not have to be searched for.
After an alert, an observer would be able to search the display screens and ascertain with a high degree of certainty whether or not a person is present.
Viewers can say with a high degree of certainty whether or not an individual shown is the same as someone they have seen before.
Picture quality and detail should be sufficient to enable the identification of an individual to be established beyond a reasonable doubt.
Dual Description -
Most cameras can be used with a dual description. This means that it can see figures at a distance which will only be for the purpose of monitoring or detecting, however the figure is able to move close enough to the camera to also be used for the purpose of recognition or even identification.