<P> Radio - frequency identification (RFID) uses electromagnetic fields to automatically identify and track tags attached to objects . The tags contain electronically - stored information . Passive tags collect energy from a nearby RFID reader's interrogating radio waves . Active tags have a local power source (such as a battery) and may operate hundreds of meters from the RFID reader . Unlike a barcode, the tag need not be within the line of sight of the reader, so it may be embedded in the tracked object . RFID is one method for Automatic Identification and Data Capture (AIDC). </P> <P> RFID tags are used in many industries, for example, an RFID tag attached to an automobile during production can be used to track its progress through the assembly line; RFID - tagged pharmaceuticals can be tracked through warehouses; and implanting RFID microchips in livestock and pets allows for positive identification of animals . </P>

Rfid tags and bar codes are used in which process