Error after pad.show()

[lucabello]

Python 3.5.3 (default, Jan 19 2017, 14:11:04)
[GCC 6.3.0 20170124] on linux
Type "help", "copyright", "credits" or "license" for more information.

>>> import spockpy
>>> pad=spockpy.HoverPad()
>>> pad.show()
>>> Exception in thread Thread-2:
Traceback (most recent call last):
  File "/usr/lib/python3.5/threading.py", line 914, in _bootstrap_inner
    self.run()
  File "/usr/lib/python3.5/threading.py", line 862, in run
    self._target(*self._args, **self._kwargs)
  File "/home/pi/opencv-test/spockpy/spockpy/io/hoverpad.py", line 94, in _showloop
    image = self.capture.read()
  File "/home/pi/opencv-test/spockpy/spockpy/io/capture.py", line 34, in read
    image    = Image.fromarray(frame)
  File "/home/pi/.virtualenvs/cv/lib/python3.5/site-packages/PIL/Image.py", line 2421, in fromarray
    arr = obj.__array_interface__
AttributeError: 'NoneType' object has no attribute '__array_interface__'