Illuminated Road Signs Can Be Good For Your Eyes; Bad For AIs

Abusing The Rolling Digital Shutters On CMOS Camera Sensors

There is yet another reason to distrust self driving cars, adding to a long list of ways to fool sensors to force them to behave in unexpected ways.  This one, which The Register found out was called ChostStripe, uses LED lighting to confuse the sensors so that they cannot recognize street signs.   The attack uses LEDs to illuminate a sign, common enough on highways to ensure we can see them with the human eyeball Mk. 1, but adds a little something.

The modified illumination looks to us to be absolutely normal, however a CMOS based camera will see rapidly changing colours as it’s capture line rolls down the sign.  This means a stop sign might start out being detected as red, but then have rainbow stripes of colour as the camera rolls down the sign.  This changing hue means that the sensor is going to pass on strange looking data to the neural net that makes the call as to whether this is a street sign or not.  It is going to discard it as not matching the expect pattern, and your self driving car will drive straight through the intersection.

As seems to have been the case for some time now, we will have safe self driving cars tomorrow … always tomorrow.

Leave a Reply