Night Vision for Drivers: Uncooled Infrared Cameras
So far, car manufacturers such as GM, Toyota, Honda, BMW or Mercedes-Benz, have all been attracted to the idea of developing night vision systems that could be installed in their vehicles.
Infrared cameras for safer road traffic
Now, the German scientists at the Fraunhofer Institute for Microelectronic Circuits and Systems IMS in Duisburg came up with another technology, based on infrared cameras. As you already know from movies and even from some computer games, these cameras can obviously see more than the naked eye and could be used for making road traffic safer.
Here is how Fraunhofer IMS support their idea:
“At night on an unlit country road: the bends in the road restrict the view ahead and, to make things worse, it is foggy. The car driver is exercising all due care and yet still does not see the deer on the road ahead until it is nearly too late. An emergency stop prevents a collision with the animal just in time. In such situations infrared cameras could provide a better level of safety.”
What's so special?
Objects at roughly body temperature are luminous in the infrared region at a wavelength of around ten micrometers. Detectors in the camera register this thermal radiation and locate the source of heat. This could enable drivers to see people or animals long before they come into vision through dipped headlights. What is extremely important to know is that other road users would not be bothered by the invisible infrared radiation.
The cameras for the long-wave infrared range have the disadvantage that the sensor requires constant cooling, adding to the cost and complexity of the device. Uncooled imagers for the long-wave infrared range already exist today, but they are mainly used in the military sphere and are more or less unavailable on the European market. However, the German institute has developed a new type of detector that works at room temperature.
How it works?
At the heart of the IRFPA (Infrared Focal Plane Array) sensor is a microbolometer – a temperature-sensitive detector that absorbs long-wave infrared light. To produce a two-dimensional image, several microbolometers are combined to form an array. If the microbolometer absorbs light from a heat source, its interior temperature rises and its electrical resistance changes. A readout chip then converts this resistance value directly into a digital signal.
According to the scientists responsible for this project, previously this was not possible without a further intermediate step – normally the electrical pulse is first translated into an analog signal and then digitized using an analog/digital converter. "We use a very specific type of converter, a sigma-delta converter, in our imager. This has enabled us to produce a digital signal directly,” explains Dirk Weiler, scientist at the IMS.
As complex and costly cooling is no longer required, further areas of application become feasible beyond the automotive sector. “Mobile devices in particular should benefit from the new development,” states Weiler.
The fact that the cooling mechanism is no longer needed not only saves weight. The battery power available and therefore the operating time of the mobile device increases because no energy is needed for cooling. The potential uses of mobile infrared cameras include firefighting, where they could detect hidden hotspots or locate people in smoke-filled buildings.
Initial laboratory tests with the new sensor element were successful and the research scientists have already been able to produce a number of infrared images.
So far, carmakers and related companies have came up with a bunch of technologies that in our opinion, take away the pleasure of driving and allow the electronic systems to dictate how a driver should react or do at any moment. Aside from making us believe that automakers are only trying to blame it on the human error, these systems could however, be a threat to the sharpness of our minds.