title: how to calculate the estimated joint probability distribution for the red and green pixels only in a png image?
body: <p>I have a png image that contains the red and green channels only.  I removed the blue channel from the image for calculation purposes.  I need to calculate the estimated joint probability distribution for these pixels.  I came across this function:
  numpy.random.multivariate_normal(mean, cov[, size])
  but this one computes the known distribution.  I need to calculate the estimated distribution.  Any suggestions?
  Thanks a lot.
  Areej</p>