filter2D: problems with large kernels (Bug #1552)

For small kernel sizes, the Python cv2-wrapper for filter2D works fine:

 1import numpy as np
 2import cv2
 3
 4# Generate a homogenous image
 5img = np.uint8(np.ones((750,1000)))
 6
 7# For a medium size kernel, the "filter2D" works
 8filterSize = 11
 9myFilter = np.ones((filterSize, filterSize))/filterSize**2
10imFiltered = cv2.filter2D(img, -1, myFilter) 
11print 'ok'

However, when the kernel gets any larger, "filter2D" crashes:

1# But for a larger kernel, it breaks
2filterSize = 13
3myFilter = np.ones((filterSize, filterSize))/filterSize**2
4imFiltered = cv2.filter2D(img, -1, myFilter)

with the error message

OpenCV Error: Assertion failed (depth == tdepth || tdepth == CV_32F) in unknown function, file ..\..\..\OpenCV-2.3.1\modules\imgproc\src\templmatch.cpp, line 61
Traceback (most recent call last):
  File "C:\Users\p20529\Coding\Python\Dev\openCV\problem.py", line 18, in <module>
    imFiltered = cv2.filter2D(img, -1, myFilter)
cv2.error: ..\..\..\OpenCV-2.3.1\modules\imgproc\src\templmatch.cpp:61: error: (-215) depth == tdepth || tdepth == CV_32F