What velocities are you looking at and are your microspheres density
neutralized?  This will help with the sticking problem.

As far as particle tracking goes, when I need to visualize flow and
quantify velocity, I image so that the particles become streaks and then
measure the length of the streaks with ImageJ
(http://rsb.info.nih.gov/ij/).  Velocity is back calculated from the
length of the streak and the camera integration time for each snapshot.
ImageJ also has some particle counting/tracking plugins that might be
useful, but I haven't explored them in much depth.

Lee Pang
[email protected]

-----Original Message-----
From: Vladimer Michael
Subject: [mems-talk] Particle tracking software for microfluidic channels

Greetings all-

  I'm looking for a software package to track microspheres in a channel.

  Specifically, I am visualizing 10um diameter microspheres in fluid
flowing through straight 100um-200um wide microchannels.  I've recorded
videos of the fluid flow shown by the moving microspheres and I'm trying

to track the microspheres to determine the fluid flow in the channel.
The problem is that some microspheres are stuck to the channel which
makes interpretation difficult.
  I've tried DiaTrack software which identifies the particles which move

as well as the particles that are stuck to the channel.  The problem is
that the software gets confused by the fixed particles and interprets
them as moving particles resulting in particle trajectories that falsely

appear to move against the flow.
  Is there a standard software package to use for 2D flow visualization?