3 ms·

The biological eye also developed based on the availability of natural electromagnetic radiation. And we are using most of the spectrum which easily passes thro

by _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?

by _ph_ 10y ago

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?