NHK Science and Technical Research Laboratories is researching a "millimeter wave television camera," which uses radio waves to take images of objects hidden by smoke or other obstacles.
"With conventional optical cameras, it's not possible to take pictures through an obstruction such as plywood. But by using millimeter waves instead of light, it is possible, because millimeter waves pass through plywood. In this demo, we actually have a piece of plywood as an obstruction, and we're filming the motion of a mannequin on the other side."
Radio wave TV cameras produce pictures by emitting millimeter waves in the 60 GHz band toward the subject, and receiving the reflections, while rapidly scanning the antenna beam up and down and left and right.
By developing a refractor array antenna that can scan the beam electronically, the frame frequency has been increased to 2.3 Hz. This is 23 times faster than with a conventional, mechanically scanning antenna.
"This camera actually sends out the signal itself, and receives the reflections from the subject. So it works using the same principle as radar. That means it can obtain information about distances in front of and behind the scene being filmed. For example, when filming the mannequin behind the plywood, by time-separating the signal reflected from the plywood and that from the mannequin, this camera can produce a picture of just the mannequin."
"This millimeter wave TV camera could be used, for example, if the site of a fire is full of smoke, or if there's been an accident in fog. We're studying whether it could be used in such emergencies, to take pictures that an optical camera can't."
From now on, NHK will test the camera further, with the aim of improving the picture quality and frame frequency.
Related Links :
- YouTube
- Millimeter-wave TV Camera
- NHK OPEN HOUSE 2010
