Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Calculating the transform matrix

  1. Oct 30, 2013 #1
    I have 2 sets of known 3x1 vectors A = [ x y 1 ] and B =[ x' y' 1 ] which represent points on two coordinates calculated by some MATLAB algorithm. I was wondering what I could do to find the 2x3 transform matrix that turns the x y set into the x' y' set.

    [x'] [ ] [x]
    [y']=[?] [y]
    [1] [1]

    B = QA

    Q = 2x3 unknown transform matrix

    What I've tried:
    multiplying both sides by A-1, and im left with A-1*B which is just a 1x1 scalar value. I've tried multiplying the variables out and I'm left with 2 equations and 6 unknowns. I also have many different values of xy & x'y' pairs given by the matlab algorithm but I dont see how that could help me. Any help is appreciated.
  2. jcsd
  3. Oct 31, 2013 #2


    User Avatar
    Science Advisor

    The system QA has two equations and six unknowns, the elements of Q. We can solve the system for these unknowns, which gives a solution with four parameters.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook