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252 lines
8.1 KiB
Python
252 lines
8.1 KiB
Python
# A binary morphology add-on for the Python Imaging Library
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#
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# History:
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# 2014-06-04 Initial version.
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#
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# Copyright (c) 2014 Dov Grobgeld <dov.grobgeld@gmail.com>
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from __future__ import print_function
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from PIL import Image
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from PIL import _imagingmorph
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import re
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LUT_SIZE = 1 << 9
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class LutBuilder(object):
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"""A class for building a MorphLut from a descriptive language
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The input patterns is a list of a strings sequences like these::
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4:(...
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.1.
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111)->1
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(whitespaces including linebreaks are ignored). The option 4
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describes a series of symmetry operations (in this case a
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4-rotation), the pattern is described by:
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- . or X - Ignore
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- 1 - Pixel is on
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- 0 - Pixel is off
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The result of the operation is described after "->" string.
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The default is to return the current pixel value, which is
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returned if no other match is found.
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Operations:
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- 4 - 4 way rotation
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- N - Negate
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- 1 - Dummy op for no other operation (an op must always be given)
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- M - Mirroring
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Example::
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lb = LutBuilder(patterns = ["4:(... .1. 111)->1"])
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lut = lb.build_lut()
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"""
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def __init__(self, patterns=None, op_name=None):
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if patterns is not None:
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self.patterns = patterns
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else:
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self.patterns = []
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self.lut = None
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if op_name is not None:
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known_patterns = {
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'corner': ['1:(... ... ...)->0',
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'4:(00. 01. ...)->1'],
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'dilation4': ['4:(... .0. .1.)->1'],
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'dilation8': ['4:(... .0. .1.)->1',
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'4:(... .0. ..1)->1'],
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'erosion4': ['4:(... .1. .0.)->0'],
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'erosion8': ['4:(... .1. .0.)->0',
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'4:(... .1. ..0)->0'],
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'edge': ['1:(... ... ...)->0',
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'4:(.0. .1. ...)->1',
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'4:(01. .1. ...)->1']
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}
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if op_name not in known_patterns:
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raise Exception('Unknown pattern '+op_name+'!')
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self.patterns = known_patterns[op_name]
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def add_patterns(self, patterns):
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self.patterns += patterns
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def build_default_lut(self):
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symbols = [0, 1]
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m = 1 << 4 # pos of current pixel
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self.lut = bytearray(symbols[(i & m) > 0] for i in range(LUT_SIZE))
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def get_lut(self):
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return self.lut
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def _string_permute(self, pattern, permutation):
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"""string_permute takes a pattern and a permutation and returns the
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string permuted according to the permutation list.
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"""
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assert(len(permutation) == 9)
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return ''.join(pattern[p] for p in permutation)
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def _pattern_permute(self, basic_pattern, options, basic_result):
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"""pattern_permute takes a basic pattern and its result and clones
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the pattern according to the modifications described in the $options
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parameter. It returns a list of all cloned patterns."""
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patterns = [(basic_pattern, basic_result)]
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# rotations
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if '4' in options:
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res = patterns[-1][1]
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for i in range(4):
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patterns.append(
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(self._string_permute(patterns[-1][0], [6, 3, 0,
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7, 4, 1,
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8, 5, 2]), res))
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# mirror
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if 'M' in options:
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n = len(patterns)
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for pattern, res in patterns[0:n]:
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patterns.append(
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(self._string_permute(pattern, [2, 1, 0,
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5, 4, 3,
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8, 7, 6]), res))
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# negate
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if 'N' in options:
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n = len(patterns)
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for pattern, res in patterns[0:n]:
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# Swap 0 and 1
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pattern = (pattern
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.replace('0', 'Z')
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.replace('1', '0')
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.replace('Z', '1'))
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res = '%d' % (1-int(res))
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patterns.append((pattern, res))
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return patterns
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def build_lut(self):
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"""Compile all patterns into a morphology lut.
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TBD :Build based on (file) morphlut:modify_lut
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"""
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self.build_default_lut()
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patterns = []
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# Parse and create symmetries of the patterns strings
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for p in self.patterns:
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m = re.search(
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r'(\w*):?\s*\((.+?)\)\s*->\s*(\d)', p.replace('\n', ''))
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if not m:
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raise Exception('Syntax error in pattern "'+p+'"')
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options = m.group(1)
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pattern = m.group(2)
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result = int(m.group(3))
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# Get rid of spaces
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pattern = pattern.replace(' ', '').replace('\n', '')
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patterns += self._pattern_permute(pattern, options, result)
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# # Debugging
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# for p,r in patterns:
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# print(p,r)
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# print('--')
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# compile the patterns into regular expressions for speed
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for i, pattern in enumerate(patterns):
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p = pattern[0].replace('.', 'X').replace('X', '[01]')
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p = re.compile(p)
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patterns[i] = (p, pattern[1])
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# Step through table and find patterns that match.
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# Note that all the patterns are searched. The last one
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# caught overrides
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for i in range(LUT_SIZE):
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# Build the bit pattern
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bitpattern = bin(i)[2:]
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bitpattern = ('0'*(9-len(bitpattern)) + bitpattern)[::-1]
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for p, r in patterns:
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if p.match(bitpattern):
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self.lut[i] = [0, 1][r]
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return self.lut
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class MorphOp(object):
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"""A class for binary morphological operators"""
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def __init__(self,
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lut=None,
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op_name=None,
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patterns=None):
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"""Create a binary morphological operator"""
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self.lut = lut
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if op_name is not None:
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self.lut = LutBuilder(op_name=op_name).build_lut()
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elif patterns is not None:
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self.lut = LutBuilder(patterns=patterns).build_lut()
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def apply(self, image):
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"""Run a single morphological operation on an image
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Returns a tuple of the number of changed pixels and the
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morphed image"""
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if self.lut is None:
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raise Exception('No operator loaded')
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if image.mode != 'L':
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raise Exception('Image must be binary, meaning it must use mode L')
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outimage = Image.new(image.mode, image.size, None)
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count = _imagingmorph.apply(
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bytes(self.lut), image.im.id, outimage.im.id)
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return count, outimage
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def match(self, image):
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"""Get a list of coordinates matching the morphological operation on
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an image.
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Returns a list of tuples of (x,y) coordinates
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of all matching pixels."""
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if self.lut is None:
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raise Exception('No operator loaded')
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if image.mode != 'L':
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raise Exception('Image must be binary, meaning it must use mode L')
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return _imagingmorph.match(bytes(self.lut), image.im.id)
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def get_on_pixels(self, image):
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"""Get a list of all turned on pixels in a binary image
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Returns a list of tuples of (x,y) coordinates
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of all matching pixels."""
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if image.mode != 'L':
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raise Exception('Image must be binary, meaning it must use mode L')
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return _imagingmorph.get_on_pixels(image.im.id)
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def load_lut(self, filename):
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"""Load an operator from an mrl file"""
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with open(filename, 'rb') as f:
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self.lut = bytearray(f.read())
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if len(self.lut) != 8192:
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self.lut = None
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raise Exception('Wrong size operator file!')
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def save_lut(self, filename):
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"""Save an operator to an mrl file"""
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if self.lut is None:
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raise Exception('No operator loaded')
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with open(filename, 'wb') as f:
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f.write(self.lut)
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def set_lut(self, lut):
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"""Set the lut from an external source"""
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self.lut = lut
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