3 ms·

I don't really see how the radar images at the bottom reflect the scene he showed. Any tips on reading those?

• hwillis 12y ago
  The radio waves are collected at points and don't have any x or y data, so making an image out of it is pretty challenging and usually requires moving the radar beam. He just kept the beam still, so the only things you can really see are things that move. In the image, the bottom axis is distance(calculated from the time the reflection took/the frequency output by the mixer), the color is the strength of the reflection, and the left axis is the time. He walked away from the setup and then back, visible as the two lines, which fade out almost completely as he changes direction, because he is far away and therefore looks smaller to the radar. http://hforsten.com/static/img/fmcw/football_field_range.png http://hforsten.com/static/img/fmcw/football_field_range.png From this data you could theoretically build an image of his upper torso and head, but it would be very blurry. His arms and legs were not static, and the radar doesn't know how they were moving, so they would just show up as blurs.
  • jkaunisv1 12y ago
    Cool, thanks! That helps a lot. Even though I knew what the axes were my intuition struggled a bit, I think partly because I'm so used to the bottom/X axis being used for time.