We are often asked this question by our partners as they are keen to ensure that the cameras they use are going to be effective.
Note that is a different question to: Can your software work with Camera X. We can work with any camera as long as it complies with an industry standard ONVIF compliant interface. And we have interfaces built for a number of camera brands that are not ONVIF compliant.
But this does not mean that the particular camera will be effective.
The question on camera specifications should normally be put to the manufacturer. They always have extensive catalogues of products, many of which would be quite suitable for a particular general surveillance task. Unfortunately, most camera manufacturers are focussed on features and cannot relate features to outcomes. Therefore, most of them are not able to say that with a particular product they would get an acceptable outcome given certain environmental conditions.
A video analytics supplier can provide general guidelines like: A 2 megapixel camera with a 50mm lens will recognize faces at 20 meters.
Unfortunately, this is insufficient as cameras are sophisticated devices with many parameters that can affect the image.
Let us explain this with one example.
If the user wishes to perform Face Recognition, he would get high accuracy with an image like the one shown as Figure 1. This image can be achieved with a 1.3 megapixel camera with a 22 mm lens at a distance of 7 meters.
The image in Figure 2 is also suitable for Face Recognition. It was also taken on a 1.3 megapixel camera with a 50mm lens at just over 10 meters.