Unexpected behavior of skimage.feature.local_binary_pattern

[msbajammal]

Hi,
The local binary pattern method in skimage is producing unexpected results. For some flat regions, it correctly produces 255 (e.g. binary 11111111). But for some other flat regions in the same image, it produces noise (decimal 85, binary 01010101).

Here is a link with code example and images to reproduce the issue:
http://stackoverflow.com/questions/42322400/unexpected-behavior-in-local-binary-pattern-python-skimage

OS version: Mac OS X 10.9.5

python version: '3.5.2 |Continuum Analytics, Inc.| (default, Jul 2 2016, 17:52:12) \n[GCC 4.2.1 Compatible Apple LLVM 4.2 (clang-425.0.28)]'

skimage.version: '0.12.3'

[stefanv]

As mentioned on the S/O question: this is because of floating point differences. If you convert the image to ubyte first, it'll work fine. Still, I see this as a usability bug.

Do you want to file a patch that issues a warning to the user if they do not use integer types with LBPs?

[anshitag]

@stefanv
Hi, I've tried to fix this issue. Please let me know if this is the correct approach.

Add these lines to the function local_binary_pattern in scikit-image/skimage/feature/texture.py

import re
from warnings import warn
match = re.search('int',str(image.dtype))
if not match:
      warn('Image data type incorrect. Use integer data types for local_binary_pattern')