undistort points instead of image

[Ana Rita Fonseca]

Does Bonsai allow for undistort node to receive as input a set of coordinates instead of an image?

The idea is to apply the undistort 'transformation' to raw x,y coordinates of center of mass

thanks

arita

[goncaloclopes]

Unfortunately, it doesn't yet, but it should, so I added it as an issue for the next version:

https://bitbucket.org/horizongir/bonsai/issue/297/add-support-for-undistortpoints

However, you can have a workaround using a PythonTransform and OpenCV UndistortPoints function. Unfortunately the code gets convoluted, but it does work. Here's an example that takes a single point and outputs the undistorted point. Hopefully you can generalize to what you need but let me know if there are any problems:

import clr
clr.AddReference("OpenCV.Net")

from System import Array
from OpenCV.Net import CV, Mat, Depth, Point2f

@returns(Point2f)
def process(input):
  # Initialize input point matrix to 2xN array of points
  points = Array[float]([input.X, input.Y])
  source = Mat.FromArray(points,points.Length/2,1,Depth.F64,2)

  # Create result matrix, will contain undistorted points
  undistorted = Array.CreateInstance(Point2f,1)
  result = Mat.CreateMatHeader(undistorted,
                               source.Rows,
                               source.Cols,
                               source.Depth,
                               source.Channels)

  # Undistortion parameters
  camera = Array[float]([1,0,320,0,1,240,0,0,1])
  cameraMatrix = Mat.FromArray(camera,3,3,Depth.F64,1)
  distortion = Mat.FromArray(Array[float]([0, 0, 0, 0, 0]))

  CV.UndistortPoints(source,result,cameraMatrix,distortion)
  return undistorted[0]

Cheers,

G