36 F Millimeter-wave TV Camera
`A Camera that Sees Invisible Objects by using Millimeter Waves`
The gMillimeter-wave TV Camerah can takes images of objects by using radio waves instead of visible light. This technology allows objects hidden behind obstacles such as smoke and fog to be seen in the images. The camera would be useful, for example, in making reports during disasters. STRL developed a new version of this camera that has a higher frame frequency than the previous one by making use of an antenna which can scan its beam faster than before.
Taking images in millimeter waves
Objects are illuminated with 60-GHz millimeter waves. The reflected waves from the objects are received with an antenna beam scanning up/down and left/right at high speed to produce a 2D image.
Increasing frame frequency by using high-speed beam scanning antenna
For the receiver, we developed a new reflectarray antenna¦1 that can scan its beam electronically. Because the electronic scan is faster than the previous mechanical scan, the new antenna increases the frame frequency of the camera to 2.3 Hz (23 times higher than that of our previous millimeter-wave TV camera).
Removing reflected waves from obstacles and background
Clear images of subjects are produced by removing reflected waves from the obstacles and background. The reflections are removed by obtaining scene information along the depth direction through an analysis of the propagation delay of the reflected waves.
In the works
We plan to continue the evaluations and increase the image quality and frame frequency.
¦1 Reflectarray antenna: a type of reflector antenna where reflector is an array of numerous reflecting elements