Local Binary Patterns

New in version 0.7: LBPs are available before, but an important bug was fixed in 0.7. It is highly recommended that you never use the older version.

Local binary patterns depend on the local region around each pixel. See the diagram below:

(Image reference: Wikipedia)

The reference pixel is in red, at the centre. A number of points are defined at a distance r from it. These are the green points. As you go from left to right, the number of green points increases.

The “pattern” in the name is the relationship of the value at the green points when compared to the central red point. We call it a binary pattern because all that is taken into account is whether the value at the green point is greater than the value at the red point.

As you can see, the green points do not necessarily fall exactly on another pixel, so we need to use interpolation to find a value for the green points.

API Documentation

The mahotas.features.lb module contains the lbp function which implements LBPs.

mahotas.features.lbp.lbp(image, radius, points, ignore_zeros=False)

Compute Linear Binary Patterns

The return value is a histogram of feature counts, where position i corresponds to the number of pixels that had code i. The codes are compressed so that impossible codes are not used. Therefore, this is the i``th feature, not just the feature with binary code ``i.

Parameters :

image : ndarray

input image (2-D numpy ndarray)

radius : number (integer or floating point)

radius (in pixels)

points : integer

nr of points to consider

ignore_zeros : boolean, optional

whether to ignore zeros (default: False)

Returns :

features : 1-D numpy ndarray

histogram of features. See above for a caveat on the interpretation of these.