CMOS Sensor Technologies – Can They Help with Traffic Congestion?


CMOS Sensor Technologies – Can They Help with Traffic Congestion?

Many of us share in the same daily frustration of sitting in slow moving traffic as we make our way to and from work. I believe that we can thank rapid population growth and urbanization for bringing about a rise in traffic that has outpaced road capacity, resulting in the loss of productive working hours, environmental pollution, wasted fuel and precious energy resources. Fortunately for all of us, new technologies are greatly improving the solutions available, each bringing their share of benefits and drawbacks.

Is there a solution to help us all get from point A to B without having to fight our way through congested roads? Although not a new alternative, road tolling is often seen as a suitable option for this complex problem. Tolling has the potential to generate the extra revenue needed to build new road infrastructures, as well as redirect traffic towards under-utilized areas to create a more efficient flow of vehicles and traffic patterns. It is seeing a renewed interest with the evolution of technologies such as Radio Frequency (RF)-based systems, and video Automatic Number or License Plate Recognition (ANPR / ALPR). These technologies are a major step forward from the coin operated toll booths many of us remember. RF systems require the installation of a transponder in each vehicle, which may not be practical for every user, and also present an initial set up cost. However, once installed RF technology is very efficient, and requires little maintenance.

Emerging high speed video technology is enabling a new generation of video based ANPR / ALPR that will be more affordable to install and much easier to maintain. Innovation in CMOS image sensor technology has led to the introduction of high definition sensors (up to 4 megapixel resolution), that can operate at speeds of 100 to 200 frames per second. To put things in perspective, this is about twice the resolution and speed of a high definition television. These new CMOS sensors offer light sensitivity that is close to that of a CCD sensor, but at a much faster frame rate. They also have the ability to freeze-frame high-speed objects such as moving vehicles, thanks to a built in electronic global shutter – an innovation for CMOS sensors. These new image sensors also eliminate the need for a separate trigger which is traditionally required to collect snapshots of moving vehicles. Their speed capabilities allow cameras to capture real-time video, which is then automatically processed by software to extract the most suitable image of the moving vehicle for the ANPR / ALPR engine. The ability to stream and capture this real-time digital video is now much easier to do thanks to a combination of these new image sensors, and high-speed data interfaces such as USB 3.0, which enables the fast and reliable transfer of such large amounts of data.

Although this is not the be-all and end-all of our traffic congestion problems, this ANPR / ALPR system architecture reduces installations cost as it relies on a lesser number of components, increases reliability by eliminating points of failure and simplifies maintenance.

Interested in reading more about CMOS sensors? Check out our Back to Basics – CCD versus CMOS Sensors blog post.