4 ms·

I always assumed that humans evolved eyes adapted to the wavelengths of light because it gave optimal information to avoid collisions. (Well, except for glass p

I always assumed that humans evolved eyes adapted to the wavelengths of light because it gave optimal information to avoid collisions. (Well, except for glass panes; we're not genetically optimized for those.) It feels scary to discard millions of years of evolution and go with radar-first, but as always, time will tell.

_ph_ 10y ago
The biological eye also developed based on the availability of natural electromagnetic radiation. And we are using most of the spectrum which easily passes through our atmosphere. Radar waves are nice in that they pass through rain and fog, but they are not well reflected by animals. So for surviving in the wild, they are less useful, but on the streets where most cars are metal-heavy they work much better. They do however not give a very well resolved picture. The radar cannot really distinguish between a bridge and a high trailer. The new software tries to work around that by using data from other Teslas passing the same road section before.
- Pyxl101 10y ago
  > The radar cannot really distinguish between a bridge and a high trailer. Are there any visualizations available of what these radar patterns look like? I wonder whether a human looking at the radar visualizations could reliably discriminate between them. I have to suspect that we could, but I've never seen such a visualization and don't have a good sense of what kind of detail it includes.
  - semi-extrinsic 10y ago
    Here is a really great writeup from a guy building his own radar. Look at e.g. the SAR images right at the end. http://hforsten.com/homemade-synthetic-aperture-radar.html http://hforsten.com/homemade-synthetic-aperture-radar.html
- jeffwass 10y ago
  Following on the parent's comment on the human eye : One of the most striking graphs I've seen was the plot of the transparency of water vs optical wavelength. Basically, there's only a tiny transparency gap, which coincides almost exactly with the wavelengths the human eye is sensitive to. http://hyperphysics.phy-astr.gsu.edu/hbase/chemical/watabs.html http://hyperphysics.phy-astr.gsu.edu/hbase/chemical/watabs.h...
- mitchty 10y ago
  I forget where I read it but I thought that the visible spectrum likely developed because it can penetrate water and that was where the first life began. Any later development of depth perception would seemingly be a tangential thing and not implicit to the wavelengths used by our eyes. Don't blue and green wavelengths pass through water rather well?
krastanov 10y ago
Humans do not have a light source and use the Sun's light. This is why we see in the "visible" spectrum. If you can bring your own well collimated coherent source you have no reason to stick to visible light. On the contrary, other spectra might be better (lower background noise, easier to produce coherently, easier to direct, etc).
- yathern 10y ago
  While I agree with your points - I would say to the contrary that roads are currently marked-up for visible spectrum usage. Road signs and lines are made for consumption within the visible spectrum - some of which may be able to be seen in other light. Though possibly an argument could be made that a self driving car doesn't need to read signs, if it can get that data from a formatted online source. (Eg street names on signs, vs from GPS and maps)
  - Piskvorrr 10y ago
    Two words: update lag. Is the "road closed this week, bridge out ahead" sign going to appear in a map? How?
Stratoscope 10y ago
I'm sorry your comment was downvoted, but thanks for taking one for the team. Whether you are right or wrong, it's exactly the kind of comment that stimulates an interesting conversation, like this one which I learned some new things from. To the downvoters: how do you expect to have an environment conducive to intellectually gratifying discussions, if you're not willing for someone to share a wild idea, and maybe even be a little bit wrong, without penalty?
ilaksh 10y ago
The scary part is that previously they were supposed to be using the cameras as primary data whereas that requires cutting edge AI that does not exist yet (nVidia and some groups making progress) and even then is limited by not being elevated and not being able to see through solid things. I would guess that Musk or someone declared that cameras would be the primary approach and the engineers below kind of had to go along with the idea on the surface, but in the actual implementation some of that really came down to what the radar was saying anyway. If this is ever going to be 'level 4' it will probably be with both an enhanced deep learning visual system (doesn't exist quite yet) and an as-yet-non-existent inexpensive elevated LIDAR. The LIDAR might come down in price within the next two or three years.

_ph_ 10y ago

The biological eye also developed based on the availability of natural electromagnetic radiation. And we are using most of the spectrum which easily passes through our atmosphere. Radar waves are nice in that they pass through rain and fog, but they are not well reflected by animals. So for surviving in the wild, they are less useful, but on the streets where most cars are metal-heavy they work much better. They do however not give a very well resolved picture. The radar cannot really distinguish between a bridge and a high trailer. The new software tries to work around that by using data from other Teslas passing the same road section before.

Pyxl101 10y ago
> The radar cannot really distinguish between a bridge and a high trailer. Are there any visualizations available of what these radar patterns look like? I wonder whether a human looking at the radar visualizations could reliably discriminate between them. I have to suspect that we could, but I've never seen such a visualization and don't have a good sense of what kind of detail it includes.
- semi-extrinsic 10y ago
  Here is a really great writeup from a guy building his own radar. Look at e.g. the SAR images right at the end. http://hforsten.com/homemade-synthetic-aperture-radar.html http://hforsten.com/homemade-synthetic-aperture-radar.html
jeffwass 10y ago
Following on the parent's comment on the human eye : One of the most striking graphs I've seen was the plot of the transparency of water vs optical wavelength. Basically, there's only a tiny transparency gap, which coincides almost exactly with the wavelengths the human eye is sensitive to. http://hyperphysics.phy-astr.gsu.edu/hbase/chemical/watabs.html http://hyperphysics.phy-astr.gsu.edu/hbase/chemical/watabs.h...
mitchty 10y ago
I forget where I read it but I thought that the visible spectrum likely developed because it can penetrate water and that was where the first life began. Any later development of depth perception would seemingly be a tangential thing and not implicit to the wavelengths used by our eyes. Don't blue and green wavelengths pass through water rather well?

krastanov 10y ago

Humans do not have a light source and use the Sun's light. This is why we see in the "visible" spectrum. If you can bring your own well collimated coherent source you have no reason to stick to visible light. On the contrary, other spectra might be better (lower background noise, easier to produce coherently, easier to direct, etc).

yathern 10y ago
While I agree with your points - I would say to the contrary that roads are currently marked-up for visible spectrum usage. Road signs and lines are made for consumption within the visible spectrum - some of which may be able to be seen in other light. Though possibly an argument could be made that a self driving car doesn't need to read signs, if it can get that data from a formatted online source. (Eg street names on signs, vs from GPS and maps)
- Piskvorrr 10y ago
  Two words: update lag. Is the "road closed this week, bridge out ahead" sign going to appear in a map? How?

Stratoscope 10y ago

I'm sorry your comment was downvoted, but thanks for taking one for the team. Whether you are right or wrong, it's exactly the kind of comment that stimulates an interesting conversation, like this one which I learned some new things from. To the downvoters: how do you expect to have an environment conducive to intellectually gratifying discussions, if you're not willing for someone to share a wild idea, and maybe even be a little bit wrong, without penalty?

ilaksh 10y ago

The scary part is that previously they were supposed to be using the cameras as primary data whereas that requires cutting edge AI that does not exist yet (nVidia and some groups making progress) and even then is limited by not being elevated and not being able to see through solid things. I would guess that Musk or someone declared that cameras would be the primary approach and the engineers below kind of had to go along with the idea on the surface, but in the actual implementation some of that really came down to what the radar was saying anyway. If this is ever going to be 'level 4' it will probably be with both an enhanced deep learning visual system (doesn't exist quite yet) and an as-yet-non-existent inexpensive elevated LIDAR. The LIDAR might come down in price within the next two or three years.