Sony has developed a CCD image sensor that can help autonomous cars make sense of electronic road signs and see better when transitioning between dark tunnels and daylight.
The IMX390 sensor has an anti-flicker function that means images of LED road signs come out clear. As LED signs are often used to indicate temporary road conditions or changes in speed limits, it’s important for an autonomous car to be able to recognize them.
On a standard sensor, LED signs appear to flicker or have a strobing effect due to a difference in the rate at which the sensor scans every second and the road sign is displayed. A similar problem is sometimes seen when a conventional camera is pointed towards a television set.
The sensor also has an HDR (high dynamic range) function that means it can see more detail in scenes with high contrast, such as when a car is entering and exiting a tunnel on a sunny day.
Typically an image sensor will be able to see either the scene outside the tunnel with the inside of the tunnel appearing black, or the other way around with the tunnel visible and the outside appearing white.
HDR helps balance this so both scenes are visible — another important feature for driverless cars so they can see the road ahead in all conditions.
Sony produced a video showing the new sensor in use versus existing sensors:
Until now, the HDR and anti-flicker technologies were available but not on the same sensor, so developers had to choose one of the other, or use two cameras. The new sensor combines both.
Sony will begin shipping samples of the image sensor this month.
The Japanese electronics company is a world leader in image sensors, producing them for both its own cameras and video cameras and those of competitors.