Super Fast Cameras

Discussion in 'General Science' started by Wendy, Sep 24, 2015.

  1. Wendy

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    nsaspook likes this.
  2. DickCappels

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    Pretty impressive. Interesting that this camera uses rotating optics like many of its predecessors.
     
  3. nsaspook

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  4. DickCappels

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    From all appearances it is the same camera.
     
  5. Wendy

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    The big difference is the bullet through the apple really was a contiguous video, while each frame of the light pulses was a separate event.
     
  6. nsaspook

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    Fundamentally there is no difference as each video pixel is a captured event and is also framed into a image with other events as a snapshot of time. These fast sampling cameras use the original electro-mechanical television principle in a much more complex way with femtosecond pulses but the pulsed light and/or spinning mirror/disk/drum raster scanning method is as old as the hills.
     
    Last edited: Sep 25, 2015
  7. Wendy

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    True enough, but for the light pulses they were each a different pulse or light, that resembled the preceding pulse, unlike the bullet which was the same object.

    Where it makes a difference is when you have a non repeating event. The still will be crisp, but the event will not be very contiguous due to the relatively slow sampling or frame rate. That is the next frontier.

    Having said that, I suspect the current tech could take some interesting slow motion pics.
     
  8. nsaspook

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    If you think about it you're not imaging the physical bullet either. You are looking at each light sample (electronic, mechanical or pulse shutter and illumination) of a reflection of light from the object retarded in time from it's actual physical position. You can see this with a strobe effect and synchronized video. By varying the phase of the shutter and modulating illumination you can adjust your relative view IRT to the motion of the object.

    Instead of modulated water droplets they are using modulated light pulses and a very ingenious shutter system to capture light.
     
  9. Wendy

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    Agreed, which is why I referred to it as a strobe effect. The bullet video would have showed one drop of water hitting a pool, the strobe technique is a repetition of similar events. While no examples (other than the bullet) come to mind there will be times you only get one shot at the video, strobe is not applicable for every case.

    Knowing the physics of how something works has always been as fascinating as the physics itself for me. There have been people who remain nameless that don't always understand that.
     
    Last edited: Sep 25, 2015
  10. Wendy

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    Interesting video. They had something at Maker Space during a show, where people had made figurines with a 3D printer, put them on belt, and strobed them. The end effect looked a lot like a moving hologram.
     
    Last edited: Sep 25, 2015
  11. nsaspook

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    I was never interested in the mathematical side of physics as a kid so it's a weak point for me but you need it at times, not to see what's possible but to know what's currently impossible quickly. It's a very good BS filter and I've found that older books do a much better job at helping you understand the basic concepts to see what's BS.
     
  12. nsaspook

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    There are other high-speed systems that can capture single events just not a light pulse.
    This is one of my fav's with a bullet.
     
    Last edited: Sep 25, 2015
  13. GopherT

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    Those textbooks are now banned... Apparently. I can't understand how the cute little examples in the margin of math and science textbooks that used to push the envelope (or prove that the envelope could only be pushed so far), have been replaced by cute pictures of kids using tablets or smart phones to help the readers think about technology. What a waste.
     
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