The Defense Advanced Research Projects Agency (DARPA), the central research and development organization of the U.S. Defense Department, has developed the Radar Scope, a portable handheld device that can penetrate 12 inches of concrete and 50 feet beyond into a room. It detects motion as slight as breathing and transmits information on where in the room the motion is occurring. With a projected cost of $1,000, this technology will soon be available to law enforcement agencies. DARPA has also developed a larger SoldierVision device, which creates a two-dimensional color image that depicts the distance to objects in motion. It penetrates 60 feet into a room and can be 30 feet from a wall and still penetrate 30 feet into the room. The pricey Camero Xaver 800 produces a three-dimensional display of a room in real time. Imaging can be achieved from up to 26 feet, with an extended imaging range of up to 65 feet. One limitation of TWS technologies is that metal in walls and metal-backed insulation can block its ability to see into a room, and most TWS technologies provide a lower resolution image than video images. The less expensive systems provide only an indicator of motion on the other side of a wall, without distinguishing what is causing the motion. In some situations, the use of this technology would constitute an unreasonable search of a home, thus requiring a warrant. The National Institute of Justice (NIJ) is currently funding an evaluation of TWS technologies in a controlled environment, which will set performance criteria, allow comparison between systems that are commercially available, and define future research and development priorities. 12 notes