ImageJ measurement of spring constant

    In this exercise, you will setup imageJ, download a movie sequence and find the mean square deviation of a bead in the movie
  1. Download GW's bead finder routine
  2. Place this into the plugins/Analyze folder of ImageJ
  3. Restart ImageJ
  4. load the image sequence as 8-bit gray scale.
  5. draw a box around the region of interest
  6. Now select Plugins > Analyze > Bead Find
  7. Adjust threshold (varies from .1 to .99 -- try a few) and select generate boundary image
  8. You should get a new set of images that look like a dark donut
  9. Once you get this, close the windows that you generated (except the original video) and rerun Bead_Find with your good parameters
  10. Copy and paste the x-y values generated into logger pro
  11. Plot the x-y data as a trajectory -- compare to a random walk
  12. Plot a histogram of N vs x and N vs y
  13. Fit a gaussian to the histogram. You may need to adjust your binning to get a good-looking gaussian.
  14. What is xave and what is the average value of x2?
  15. What are the units?
  16. How will you calibrate the setup?