The Hindu Business Line : Infrared devices: An eye beyond visual range

Infrared rays find a number of applications in the field of medical diagnostics and treatment. Special infrared (IR) cameras are also used for thermal imaging stress tests to detect structural weak spots. Such tests are conducted by infrastructure developers and the automotive industry. Many mobile phones have an IR port for transfer of data to and from another infrared-enabled cell phone or hand-held device. Infrared has also been used by the military in night vision equipment.

One of the most exciting new applications of infrared is in some of the new high-end cars. IR’s popularity amongst the major premium car manufacturers is due largely to the increasing demand for improved safety for both the occupants and and road users. Special IR cameras and sensors are finding their way into a car’s on-board systems, so that they can act as warning devices for the driver.

Improved Visibility

The primary application that revolves around IR cameras and sensors is to improve visibility of the road in low light conditions such as at night or in foggy conditions. Clubbed with the right hardware, such as an on-board display, IR systems literally enable the driver to see the road ahead even in extremely dark conditions.

These systems were originally designed and developed for use in Europe, where highways are mostly unlit and where animal crossing is common.

The initial idea for using IR in cars came up when manufacturers were looking for a solution to improve visibility at the blind spots of the car. Early experiments with IR sensors involved using them, one on either side of the car, to warn the driver of the presence of another vehicle or obstacle at the two blind spots, beyond the reach of the outside rear-view mirrors.

Then innovations were made and technologies developed by both component makers and automobile companies that have enabled the integration of IR cameras into the car’s electronics. The principle behind these devices is to make visible to the driver objects beyond the car headlamp beam and not visible to the naked eye.

Real-Time Image

In a few high-end cars that feature this technology, IR cameras are usually located just behind the bonnet grille to enable it to capture the image of oncoming vehicles, people, animals and other obstacles.

The IR camera is put together with electronics that enable the capture of the real-time infrared image feed onto a LCD display screen, which is mounted on the vehicle’s dashboard or in some cases on a head-up display.

IR cameras and devices for automobile applications have become more powerful and sophisticated over the past few years. During the first few years of development, some of the systems involved the use of an IR light source and were called Near-IR.

These systems enabled the vehicle mounted IR light source to capture the infrared rays bouncing off objects on the road, which was then fed onto an on-board display.

Current IR systems that find application in cars are the more popular Far-IR type and involve the use of an on-board IR detection system, which simply scans the road ahead for heat sources.

Since, live obstacles such as animals and humans possess body heat that is higher than the surrounding objects, they get identified as potential threats and the on-board computer then creates a visual for the driver.

More Reliable

Unlike Near-IR devices, which offer a streaming video with IR highlights of the exact situation of the road ahead, Far-IR devices will only enable the driver get a visual representation or a thermal image of the road and the obstacles. The systems are more reliable though thanks to a complicated, computerised system that maps the thermal source to exactly identify what kind of threat it represents.

Moreover, unlike Near-IR, which has a range of only about 100 metres, Far-IR has much longer (up to five times more) range and can pick-out potential threats from afar, dramatically improving the reaction time for the driver and thereby improving safety for him and for those on the road. It is estimated that Far-IR systems can improve the safety factor four-fold.

Car IR devices have been connected to other equipment to improve functionality, such as in complimentary systems which detect the driver’s steering wheel inputs (while turning) and use it to enable the IR camera or device to pan and preempt the car’s change in direction. IR inputs can also be used to activate pre-safety procedures, including active braking (automatic self-braking).

Car IR systems are as yet an expensive addition and are part of standard fitment only in high-end super-luxury cars.