filter convolution

[dnarayanan]

currently throwing some h5 error:

 ----------              ------
  8.50E+02              1.00E+00
  1.30E+03              1.00E+00
Traceback (most recent call last):
  File "/home/desika.narayanan/miniconda3/envs/pd3env/bin/pd_front_end.py", line 4, in <module>
    __import__('pkg_resources').run_script('powderday==0.1.0', 'pd_front_end.py')
  File "/home/desika.narayanan/miniconda3/envs/pd3env/lib/python3.6/site-packages/pkg_resources/__init__.py", line 666, in run_script
    self.require(requires)[0].run_script(script_name, ns)
  File "/home/desika.narayanan/miniconda3/envs/pd3env/lib/python3.6/site-packages/pkg_resources/__init__.py", line 1469, in run_script
    exec(script_code, namespace, namespace)
  File "/home/desika.narayanan/miniconda3/envs/pd3env/lib/python3.6/site-packages/powderday-0.1.0-py3.6.egg/EGG-INFO/scripts/pd_front_end.py", line 306, in <module>
  File "/home/desika.narayanan/miniconda3/envs/pd3env/lib/python3.6/site-packages/powderday-0.1.0-py3.6.egg/powderday/image_processing.py", line 97, in convolve
  File "/home/desika.narayanan/miniconda3/envs/pd3env/lib/python3.6/site-packages/h5py/_hl/group.py", line 136, in create_dataset
    dsid = dataset.make_new_dset(self, shape, dtype, data, **kwds)
  File "/home/desika.narayanan/miniconda3/envs/pd3env/lib/python3.6/site-packages/h5py/_hl/dataset.py", line 118, in make_new_dset
    tid = h5t.py_create(dtype, logical=1)
  File "h5py/h5t.pyx", line 1634, in h5py.h5t.py_create
  File "h5py/h5t.pyx", line 1656, in h5py.h5t.py_create
  File "h5py/h5t.pyx", line 1717, in h5py.h5t.py_create
TypeError: No conversion path for dtype: dtype('<U20')```