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- from Histogram import Histogram
- from math import ceil
- class LocalBinaryPatternizer:
- def __init__(self, image, cell_size=16):
- self.cell_size = cell_size
- self.image = image
- self.setup_histograms()
- def setup_histograms(self):
- cells_in_width = int(ceil(self.image.width / float(self.cell_size)))
- cells_in_height = int(ceil(self.image.height / float(self.cell_size)))
- self.features = []
- for i in xrange(cells_in_height):
- self.features.append([])
- for j in xrange(cells_in_width):
- self.features[i].append(Histogram(256,0,256))
- def create_features_vector(self):
- ''' Walk around the pixels in clokwise order, shifting 1 bit less
- at each neighbour starting at 7 in the top-left corner. This gives a
- 8-bit feature number of a pixel'''
- for y, x, value in self.image:
- pattern = (self.is_pixel_darker(y - 1, x - 1, value) << 7) \
- | (self.is_pixel_darker(y - 1, x , value) << 6) \
- | (self.is_pixel_darker(y - 1, x + 1, value) << 5) \
- | (self.is_pixel_darker(y , x + 1, value) << 4) \
- | (self.is_pixel_darker(y + 1, x + 1, value) << 3) \
- | (self.is_pixel_darker(y + 1, x , value) << 2) \
- | (self.is_pixel_darker(y + 1, x - 1, value) << 1) \
- | (self.is_pixel_darker(y , x - 1, value) << 0)
- cy, cx = self.get_cell_index(y, x)
- self.features[cy][cx].add(pattern)
- return self.get_features_as_array()
- def is_pixel_darker(self, y, x, value):
- return self.image.in_bounds(y, x) and self.image[y, x] > value
- def get_cell_index(self, y, x):
- return (y / self.cell_size, x / self.cell_size)
- def get_features_as_array(self):
- return [h.bins for h in [h for sub in self.features for h in sub]][0]
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