[wilg]

Can you elaborate on your reasoning? I’m shaky on some of logic here.

“Monocular” cameras > no “absolute” depth > less safe

The last leap is not well justified.

Also, cars with vision based driving have multiple cameras. Whats the difference between a “binocular” camera and two “monocular” cameras?

How does a “binocular” camera get better depth information?

Is using multiple cameras to drive sensor fusion?

Why is absolute depth a strict safety win? How do you know how the sensor details translate to the final safety of the full system?

If this is just a handwavey upper bound on safety, how do you know that such a system can’t be safe enough for its design goals?

If humans with only one eye are able to drive, why wouldn’t mono surround vision be at least as good as that?

[green_man_lives]

I am just a hobbyist but I can answer some of these.

> Whats the difference between a “binocular” camera and two “monocular” cameras?

For the camera itself, nothing. They are probably referring to the implementation. You can have two cameras side by side but unless you are using homography to estimate depth from the two images, then your setup is monocular.

> How does a “binocular” camera get better depth information?

A pixel in two images (with known separation) will have a geometric relationship that can be used to extract depth information. This is a lot faster than alternative methods with a single camera and multiple images.

> Is using multiple cameras to drive sensor fusion?

This is really just a question of semantics.

> Why is absolute depth a strict safety win?

Why is it better to have two eyes than one? You can be more certain about what you are seeing.

> If this is just a handwavey upper bound on safety, how do you know that such a system can’t be safe enough for its design goals?

If you had a system with infinite compute you could probably do enough math to calculate absolute depth with 100% certainty. I believe you can already extract absolute depth with something called bundle adjustment-- but it requires multiple images since you are relying on parallax effects. It is also computationally expensive.

> If humans with only one eye are able to drive, why wouldn’t mono surround vision be at least as good as that?

Computers are not humans.

[michaelt]

> Why is absolute depth a strict safety win? How do you know how the sensor details translate to the final safety of the full system?

If you can get reliable depth information, the algorithm needed to avoid hitting stationary and slow-moving objects is extremely simple.

Is the stationary object in our path, of nontrivial size, and about to enter our minimum stopping distance? If yes, do we have a swerve planned that will let us safely avoid it? If no, emergency stop.

Because this logic is simple and well defined you can audit the implementation to the high standards applied to things like aircraft autopilot systems.

And it'll work even if the stationary object is something that didn't appear in your training data - you know the algorithm will work the same even if that concrete barrier is painted with some cheery flowers, or if that fire truck is airport yellow instead of the normal red.

Of course, this relies on the assumption you can get reliable depth information. If your depth sensor gets confused by a cloud of dust while driving in the desert, or gets blinded by the light of the setting sun, or is unable to detect a barbed wire fence, things are no longer quite so simple....

> If this is just a handwavey upper bound on safety, how do you know that such a system can’t be safe enough for its design goals?

Personally I would say that in freeway driving, a self-driving car should be able to avoid 100% of collisions with clearly visible stationary objects in dry, well lit conditions when all system components are in normal working condition.