Values you might want to change:

N.repeat(self.pos, 1, axis=0)
Make 1 particle per pixel in the text (try 4)

self.pt_start_time = 1 + self.pos[:,0] / W * 6
Do nothing for the first second, then take 6 seconds to sweep over the image

self.escape_vel = N.random.randn(npts, 3) * 5
Rate of flying particles

N.hamming(50)
Smoothing factor for velocities. Disable this section to get random noise.

dpi=int(H * .6)
Overall scaling factor for the font sizes.

coords = N.fliplr(N.transpose(N.nonzero(data > 128)))
Threshold brightness value for which we make a particle.

self.vel[:,1] += self.escaped_pts * -2
Gravity.

zscl = .1
Stereo offset between left and right eye.