Question

Say I am tracking 2 objects moving in space & time,

• I know their x,y co-ords and score (score being a probabilistic
  measure of the tracked being the actual object),
• and I get several
  such {x,y,score} samples over time for each object

What metric would I use to measure “similarity” of say a ball moving across a room vs. man moving across the room vs. a child moving across the room.

Assume the score is pretty accurate.

Answer 1

Given your description, I’d recommend looking into a Hidden Markov Model or possibly an artificial neural network or some other machine learning approach. However, there are a number of other techniques that might be more appropriate for your situation.