# ValueError: setting an array element with a sequence.

hi first i computed a Mapping Matrix named homography using findHomography command

```
M, mask = cv2.findHomography(src_pts, dst_pts, cv2.RANSAC, 5.0)
homography = M, mask
```

then I defined a 3*3 Matrix named camera as camera = np.array([[800, 0, 240], [0, 800, 320], [0, 0, 1]]) and I Globalized this variable (camera) and defined a Function named (projection_matrix) :

```
global camera
camera = np.array([[800, 0, 240], [0, 800, 320], [0, 0, 1]])
def projection_matrix(homography):
```

then I called this Function. I want to Multiply Inversion Matrix Of camera to homography Mapping Matrix as:

```
homography = homography * (-1)
projection_matrix(homography)
```

# Multiply Inversion Matrix Of camera to homography Matrix

```
rot_and_transl = np.dot(np.linalg.inv(camera), homography)
```

but Pycharm gives These Errors:

```
**TypeError: only size-1 arrays can be converted to Python scalars**
```

The above exception was the direct cause of the following exception:

Traceback (most recent call last): File "C:/Users/Ali Hoseyni/PycharmProjects/pythonProject/main.py", line 41, in <module>

rot_and_transl = np.dot(np.linalg.inv(camera), homography) File "<__array_function__ internals>", line 5, in dot

```
**ValueError: setting an array element with a sequence.**
```

what are you trying to achieve here ? what's the context ?

this does not make much sense. did you want ot invert the homography instead ?

also, your "homography" is a tuple of 2 Mats, for sure the wrong thing

last, if you wanted the combined homography / camera transform, you need a matrix multiplcation, not a dot product