NEXYAD software modules may allow to avoid some accident like auto-pilot TESLA car recently had

Passions run around the issue of autonomous vehicles, or semi-autonomous. Recently with a TESLA car there has been a fatal

accident while on autopilot mode. NEXYAD studied traffic safety for twenty years, and we give some elements of reflection on this

type of accident.


Processing circuit, informing auti-pilot systems, control, etc ... from perception, data fusion, decision-making, and automatic control of actuators,

are usually very well designed, and based on high-performance modules. But unfortunately, this is not enough to void the the risk of accidents.

Indeed, for the treatment of this risk, it lacks a parallel circuit (oarallel and independent) called "monitoring" circuit.

To understand this need for a monitoring circuit, one must first understand the level of complexity of a road scene viewed from a camera.


The variability of road scenes is actually much more than what a normal person comes to Imagine. Indeed, a color image, which has eight bits

for each color (then, 24-bit, as there are 3 colors) may encode 224 different color levels per pixel (more than 65,000 different possible values).

HD video has more than 2 million pixels.

This means that the matrix of HD 8-bit color image may encode  more than 65 000 2 000 000 images !

This huge number is simply unimaginable.


This raises the question of the validation process of driver assistance systems (ADAS) based on cameras. It really is impossible to test all possible
cases of road scenes ! Even one or ten million kilometers of testing represents a negligeable part of possible cases !

And please do not think that you can easily reduce this complexity, assuming that road scenes have a "SPECIFIC SHAPE" (the road in front of the car).

You may then be surprised ifever a spider settled in front of the camera lens ... or if the car is behind a truck or bus with an adds poster (and in such a
case, all images are possible, including the image of a straight road in the desert, while the actual road, the one on which the vehicle sets, turns !).


Completeness of validation database is impossible, however, there is a solution to use in such a case. First, build the validation database using
a methodology (NEXYAD has been publishing the « AGENDA » methodology in the field of ADAS validation, see ). And second, use in real time a parallel circuit of « monitoring » that has the role of « closing »

the open world.  In other words, it is necessary that all cases already met in the validation process are used to create  a kind of "confined space" called "known space".

Then, in real time while vehicle is driving, one check if the current case (what is seen NOW by cameras, and other sensors) is INSIDE this « known space »

so that the built-in intelligence to know if the road scene meets cases in which it can react properly, or if the road scene is very different (unknown case).

In the second case, it is obvious that embedded intelligence must take default decisions : slowdown, warns the driver, etc ...


Therefore, in parallel of the construction of the main auto-pilot chain of perception, intelligence and control , it is necessary to build a second circuit for case monitoring.
NEXYAD has been developing three software modules aimed at achieving this kind of monitoring circuit.

Read more :