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Jun. 16th, 2004 10:12 am![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
meanfreepathI'm updating my LJ in lab right now because I'm waiting for these video images to be exported as TIFF files so that I can run the analysis code on them. The code is supposed to track individual particles and measure their velocities. I think it also does some FFT (fast Fourier transform) thing on the data.
The point of all of this is to find the camera that has the best signal-to-noise ratio. This will be important when we image a real dusty plasma crystal lattice. For these tests, I had a bunch of slides fabricated, basically little white dots on a black background. Backlighting the slides gives you something that looks very much like a real lattice. There should be no thermal motion in the fake lattice (unlike what happens in the real plasma crystal) so the particles should have 0 velocity. That isn't true b/c of noise in the CCD's on the cameras. We'll choose the camera with the lowest mean squared velocity and the sharpest pair correlation function g(r). On the pair correlation function, which shows the number of particles at a given distance from all particles, the peaks should approximate delta functions in a perfect crystal, which the fake lattice is.
Right now, I'm sick to my stomach. I went to breakfast at the Cottage Bakery near Van Allen Hall, having gone running and just missed breakfast at the Burge Dining Hall. I ordered some coffeecake, on the recommendation of one of the physics students here, and a small muffin. I would not have ordered the muffin had I known that the pieces of coffeecake they served up were the size of pocket dictionaries. I'm not used to eating nearly this large a quantity of rich food for breakfast. It may well take me a few hours to get over this...
The point of all of this is to find the camera that has the best signal-to-noise ratio. This will be important when we image a real dusty plasma crystal lattice. For these tests, I had a bunch of slides fabricated, basically little white dots on a black background. Backlighting the slides gives you something that looks very much like a real lattice. There should be no thermal motion in the fake lattice (unlike what happens in the real plasma crystal) so the particles should have 0 velocity. That isn't true b/c of noise in the CCD's on the cameras. We'll choose the camera with the lowest mean squared velocity and the sharpest pair correlation function g(r). On the pair correlation function, which shows the number of particles at a given distance from all particles, the peaks should approximate delta functions in a perfect crystal, which the fake lattice is.
Right now, I'm sick to my stomach. I went to breakfast at the Cottage Bakery near Van Allen Hall, having gone running and just missed breakfast at the Burge Dining Hall. I ordered some coffeecake, on the recommendation of one of the physics students here, and a small muffin. I would not have ordered the muffin had I known that the pieces of coffeecake they served up were the size of pocket dictionaries. I'm not used to eating nearly this large a quantity of rich food for breakfast. It may well take me a few hours to get over this...
