Time-of-Flight (ToF)

The research team from the Heriot-Watt University in Edinburgh, Scotland, led by Gerald Buller, has developed a new system consisting of a camera and a laser that can create a three-dimensional image with a relatively high resolution from a distance of up to one kilometer. The system works by measuring laser light transmission time to the object of interest and back to the sensor of highly sensitive camera. This technology called "time-of-flight" (ToF) measuring is widely used in different systems of navigation of autonomous cars and robots. The new system operates by scanning by a beam of low-power infrared light object of interest, located in a far distance. This technology allows to measure the time of flight of photons there and back for each pixel of the future image. On the first picture there are examples of images of objects made by the new system from a distance of 325 meters. On the left one can see a picture of the object, made by a normal camera. A color code in the right is a map showing the number of photons of laser light that reached the goal, turned back and were checked by the camera sensor. The researchers point out that human skin has special properties of infrared light, which do not allow high-quality scans. The resulting data contain information about the depth, but they are not enough to restore a human face image.

At the second picture one can see examples of pictures taken by the system from a distance of 910 meters. As one can see, the quality of a produced image depends directly on the scan time, because the longer the system scans the object, the more photons camera sensor detects and the more accurate information about the depth the system receives.

In spite of such a low quality picture from the human eye point of view, the system can have a very wide application because of its many positive qualities listed above. And high quality of the picture is not always required. For several navigation systems and object recognition systems installed on industrial robots and military equipment a new system will be more than enough