Self-driving cars have undoubtedly been in the limelight for some time now. Beyond any question, it is going to be the next big thing which will carry the torch of the new-age technology. We are accustomed to believe that it will be a decade or two before we see one on the roads. Let me tell you, it is not so! Researchers of the Camera Culture group at MIT’s Media Lab have seen to it. They have developed new sensors for time-of-flight (ToF) Imaging system that provides a very high depth resolution of the objects.
For an object 2 metres away from the sensors the depth resolution is about 3 micrometres. Basically, ToF is an imaging system that projects light wave in different directions between very short intervals of time. It then records the time taken by the wave that hits the object to travel back and calculates the distance of the object from the sensor. Also, the wave goes through a change in phase after bouncing back from the object.
This change in phase determines the orientation of the object through certain algorithms.The sensors developed by the researchers can make self- driving cars practical. They applied the concept of beats that is used in acoustics to the light pulses. For an example, if a ToF system is firing light on an object at a rate of 1,000,000,000 (billion) pulses per second, then the reflected light wave is combined with a light wave pulsing 999,999,999 times a second and the result will be a light wave pulsating once per second which is easy to detect by the light capturing sensors. This is similar to ‘beat’ and provides phase information which is used to collect data.
What the researchers did is that they modulated the reflected wave by employing the similar technology that is used to produce the wave. It simply means that the already pulsed light is pulsed again. This approach can be a game changer for self driving cars.The major obstacle in the development of self driving cars is fog as it scatters light and deflects them at odd angles. This problem can be tackled by the new system. The high frequency (Gigahertz) light waves used in the system are inherently found to be more effective than the low frequency ones. Low frequency waves scatter the light and cause a slight shift in phase, which gives inaccurate data, but with high frequency systems the phase shift is quite large.
Therefore, when these scattered light signals meet, they actually cancel out each other. This cancellation helps in recognising the true signal easily.With this new innovation, the development of the self-driving car will certainly make a leap.