How to Select the Resolution you will need
The resolution defines the detail that you will see. I have talked to a number of people who have video surveillance camera systems and find that the video that they stored is not clear enough to make out a person’s face. This is because they don’t have enough
Resolution is important if you are trying to view a person’s face (or a license plate number) in a large area. This is especially true if the object you are trying to view takes up a small part of the overall picture. The wider the area you want to view the more resolution you need to see all the detail.
There was a study done by the US government that determined that you need 50 pixels per foot to identify a person’s face or read a license plate number. So if you have a 700 x 480 pixel camera it can view an area that is 14 feet wide (700 pixels/50 = 14). If you want to view a larger area, you need more pixels (higher resolution). A camera with a resolution of 1600 x 1200 can view an area that's about 32 feet wide. Take a look at http://www.kintronics.com/iqinvision/IQe3spec.htm for examples of high resolution IP cameras.