How to correlate a matrix of values to get a coordinated point?
I finally managed to get what I want. I used python's scipy's

interpolate.RectBivariateSpline(x,y,z,kx,ky)


to create a 60x60 matrix out of the 3x3 matrix. And out of that, I used opencv libraries to detect blobs (mainly, findContours() and fitEllipse()), so now I got a list of ellipses matching the several touches I have.