Radar and imaging technology

  • #1
LightningInAJar
168
21
TL;DR Summary
Using technology to detect 3D space.
I was wondering if radar is safe, can it detect near objects (lets say 50 feet away) and does it accurately see 3D shapes? I am looking for a technology that could maybe supplement augmented reality in the sense that VR objects can be given GPS locations, but don't know if there is something in front or behind it in real life and therefore always appears in foreground. Any ideas?
 

Answers and Replies

  • #2
Baluncore
Science Advisor
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RADAR is more advanced than you may think. Your wifi signals are reflected by people in the next room. With several receivers and a correlator, you can make a 3D image of the people moving in the next room, through the wall. They do not know you are watching, and the wifi still works.
 
  • #3
artis
1,330
882
@LightningInAJar Well it depends on what application you want to use it for.
Radiowaves have longer wavelengths than visible light for example so if you want to accurately identify small objects close to you you might be better off with a visual video input, or combine both.
 
  • #4
Tom.G
Science Advisor
Gold Member
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Using the parallax (Google it) from stereo vision should be much easier, and safer, to implement.
https://www.google.com/search?&q=stereo+camera+depth+estimation
(for some other hints, also try searching for: stereo camera depth)

I seem to recall that a few years ago there were some gaming/VR devices on the market that used that approach. (Microsoft maybe?)

Cheers,
Tom
 
  • #6
LightningInAJar
168
21
RADAR is more advanced than you may think. Your wifi signals are reflected by people in the next room. With several receivers and a correlator, you can make a 3D image of the people moving in the next room, through the wall. They do not know you are watching, and the wifi still works.
Would that be a pricey project? I assume not portable everywhere a person goes?
 
  • #7
Baluncore
Science Advisor
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Would that be a pricey project?
Everything is more pricey than you would like.
I think you must search and review the literature available.

It seems you are rendering virtual objects into or onto the visual real world.
Optical LIDAR may be more applicable to that task because you do not want to see through walls.

What would you like to happen when you encounter a glass wall, a thin curtain, or a mirror.
 
  • #8
artis
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882
Optical LIDAR may be more applicable to that task because you do not want to see through walls.
I think the seeing through walls is not straight forward is it? Small walls made from non conducting materials maybe yes, but normal reinforced concrete or thick masonry walls or walls with metal in them would a radar really see through them?
 
  • #9
Baluncore
Science Advisor
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I think the seeing through walls is not straight forward is it? Small walls made from non conducting materials maybe yes, but normal reinforced concrete or thick masonry walls or walls with metal in them would a radar really see through them?
If wifi passes through the wall, then where is the problem?

It will depend on the wavelength of the wifi and the number of antennas. Wifi frequencies are still rising. The wavelengths available are now significantly shorter than the holes in reinforcing mesh.

One bright point reflector, moving on the other side of the wall, should be sufficient to characterise the wall as a fixed array of scaterers. It should then be possible to deconvolve the reflections from the other side of the wall, creating a 3D image. It would still be possible without the bright point, but it would take longer to establish the matrix.
 

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