python cv2.calibrateCamera throws error: objectPoints should contain vector of vectors of points of type Point3f

Question

I have the code

img = cv2.imread(\"poolPictures\\chessboard3.jpg\", cv2.IMREAD_COLOR)
chessboardImage = cv2.imread(\"poolPictures\\chessboardActual.jpg\", c         


        

Answer 1

As Zenith042 pointed out, I had image points and object points the wrong way round. However, the main issue was that instead of a numpy array for my image points like:

[[[ 137.5  205. ]]
[[ 143.5  206.5]]
 .
 .
 .
[[ 137.5  209.5]]]

I instead needed:

[[ 137.5 205. ]
[ 143.5 206.5]
.
.
.
[ 137.5 209.5]]]

Which I achieved with:

ret, corners = cv2.findChessboardCorners(img, (9,6), None)
corners = np.array([[corner for [corner] in corners]])

although I suspect there is a nicer way with numpy.reshape.

I also needed the same structure for the object points, i.e.

objp = np.array([objp])