Hidden cameras have become an increasingly popular item to get surveillance over a designated area. They record images in a certain field of vision. They are cleverely hidden in plain sight and come in many forms such as a trash can, coat hanger, pepsi bottle, etc.
Hidden cameras are mainly used for security. Most places such as police stations, hospitals, department stores use hidden security cameras.
When hidden cameras first started out they where big clunky devices with less than perfect recordings. They were pretty obvious to detect and not very effective for their purpose. Now they are smaller with clear, concise recordings and very well hidden in plain sight.
The hidden cameras are also used at traffic signals and can be used in some states to ticket people or help avoid accidents. They are controversial in the sense that people think they are being presumed guilty. I myself think they are necessary to protect a person against deception and false statements. It is a controversial issue that is ongoing in different states. Some people think that the use of them in hotels could be used for pornographic purposes for the internet. No matter what you may think they are here to stay and are being used all over the world for safet, security, and prevention of crime.