libvips/test/test_convolution.py

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2014-12-15 17:14:02 +01:00
#!/usr/bin/python3
from __future__ import division
from numbers import Number
from functools import reduce
import unittest
import operator
import math
#import logging
#logging.basicConfig(level = logging.DEBUG)
from gi.repository import Vips
unsigned_formats = [Vips.BandFormat.UCHAR,
Vips.BandFormat.USHORT,
Vips.BandFormat.UINT]
signed_formats = [Vips.BandFormat.CHAR,
Vips.BandFormat.SHORT,
Vips.BandFormat.INT]
float_formats = [Vips.BandFormat.FLOAT,
Vips.BandFormat.DOUBLE]
complex_formats = [Vips.BandFormat.COMPLEX,
Vips.BandFormat.DPCOMPLEX]
int_formats = unsigned_formats + signed_formats
noncomplex_formats = int_formats + float_formats
all_formats = int_formats + float_formats + complex_formats
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# an expanding zip ... if either of the args is a scalar or a one-element list,
# duplicate it down the other side
def zip_expand(x, y):
# handle singleton list case
if isinstance(x, list) and len(x) == 1:
x = x[0]
if isinstance(y, list) and len(y) == 1:
y = y[0]
if isinstance(x, list) and isinstance(y, list):
return list(zip(x, y))
elif isinstance(x, list):
return [[i, y] for i in x]
elif isinstance(y, list):
return [[x, j] for j in y]
else:
return [[x, y]]
# run a 1-ary function on a thing -- loop over elements if the
# thing is a list
def run_fn(fn, x):
if isinstance(x, list):
return [fn(i) for i in x]
else:
return fn(x)
# run a 2-ary function on two things -- loop over elements pairwise if the
# things are lists
def run_fn2(fn, x, y):
if isinstance(x, Vips.Image) or isinstance(y, Vips.Image):
return fn(x, y)
elif isinstance(x, list) or isinstance(y, list):
return [fn(i, j) for i, j in zip_expand(x, y)]
else:
return fn(x, y)
# point convolution
def conv(image, mask, x_position, y_position):
s = 0.0
for x in range(0, mask.width):
for y in range(0, mask.height):
m = mask.getpoint(x, y)
i = image.getpoint(x + x_position, y + y_position)
p = run_fn2(operator.mul, m, i)
s = run_fn2(operator.add, s, p)
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return run_fn2(operator.truediv, s, mask.get_scale())
def compass(image, mask, x_position, y_position, n_rot, fn):
acc = []
for i in range(0, n_rot):
result = conv(image, mask, x_position, y_position)
result = run_fn(abs, result)
acc.append(result)
mask = mask.rot45()
return reduce(lambda a, b: run_fn2(fn, a, b), acc)
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class TestConvolution(unittest.TestCase):
# test a pair of things which can be lists for approx. equality
def assertAlmostEqualObjects(self, a, b, places = 4, msg = ''):
#print 'assertAlmostEqualObjects %s = %s' % (a, b)
for x, y in zip_expand(a, b):
self.assertAlmostEqual(x, y, places = places, msg = msg)
def setUp(self):
im = Vips.Image.mask_ideal(100, 100, 0.5, reject = True, optical = True)
self.colour = im * [1, 2, 3] + [2, 3, 4]
self.mono = self.colour.extract_band(1)
self.all_images = [self.mono, self.colour]
self.sharp = Vips.Image.new_from_array([[-1, -1, -1],
[-1, 16, -1],
[-1, -1, -1]], scale = 8)
self.blur = Vips.Image.new_from_array([[1, 1, 1],
[1, 1, 1],
[1, 1, 1]], scale = 9)
self.line = Vips.Image.new_from_array([[ 1, 1, 1],
[-2, -2, -2],
[ 1, 1, 1]])
self.sobel = Vips.Image.new_from_array([[ 1, 2, 1],
[ 0, 0, 0],
[-1, -2, -1]])
self.all_masks = [self.sharp, self.blur, self.line, self.sobel]
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def test_conv(self):
for im in self.all_images:
for msk in self.all_masks:
for prec in [Vips.Precision.INTEGER, Vips.Precision.FLOAT]:
convolved = im.conv(msk, precision = prec)
result = convolved.getpoint(25, 50)
true = conv(im, msk, 24, 49)
self.assertAlmostEqualObjects(result, true)
result = convolved.getpoint(50, 50)
true = conv(im, msk, 49, 49)
self.assertAlmostEqualObjects(result, true)
def test_compass(self):
for im in self.all_images:
for msk in self.all_masks:
for prec in [Vips.Precision.INTEGER, Vips.Precision.FLOAT]:
for times in range(1, 4):
convolved = im.compass(msk,
times = times,
angle = Vips.Angle45.D45,
combine = Vips.Combine.MAX,
precision = prec)
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result = convolved.getpoint(25, 50)
true = compass(im, msk, 24, 49, times, max)
self.assertAlmostEqualObjects(result, true)
for im in self.all_images:
for msk in self.all_masks:
for prec in [Vips.Precision.INTEGER, Vips.Precision.FLOAT]:
for times in range(1, 4):
convolved = im.compass(msk,
times = times,
angle = Vips.Angle45.D45,
combine = Vips.Combine.SUM,
precision = prec)
result = convolved.getpoint(25, 50)
true = compass(im, msk, 24, 49, times, operator.add)
self.assertAlmostEqualObjects(result, true)
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def test_convsep(self):
for im in self.all_images:
for prec in [Vips.Precision.INTEGER, Vips.Precision.FLOAT]:
gmask = Vips.Image.gaussmat(2, 0.1,
precision = prec)
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gmask_sep = Vips.Image.gaussmat(2, 0.1,
separable = True,
precision = prec)
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self.assertEqual(gmask.width, gmask.height)
self.assertEqual(gmask_sep.width, gmask.width)
self.assertEqual(gmask_sep.height, 1)
a = im.conv(gmask, precision = prec)
b = im.convsep(gmask_sep, precision = prec)
a_point = a.getpoint(25, 50)
b_point = b.getpoint(25, 50)
self.assertAlmostEqualObjects(a_point, b_point, places = 1)
def test_fastcor(self):
for im in self.all_images:
for fmt in noncomplex_formats:
small = im.crop(20, 45, 10, 10).cast(fmt)
cor = im.fastcor(small)
v, x, y = cor.minpos()
self.assertEqual(v, 0)
self.assertEqual(x, 25)
self.assertEqual(y, 50)
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def test_spcor(self):
for im in self.all_images:
for fmt in noncomplex_formats:
small = im.crop(20, 45, 10, 10).cast(fmt)
cor = im.spcor(small)
v, x, y = cor.maxpos()
self.assertEqual(v, 1.0)
self.assertEqual(x, 25)
self.assertEqual(y, 50)
def test_gaussblur(self):
for im in self.all_images:
for prec in [Vips.Precision.INTEGER, Vips.Precision.FLOAT]:
for i in range(5, 10):
sigma = i / 5.0
gmask = Vips.Image.gaussmat(sigma, 0.2,
precision = prec)
a = im.conv(gmask, precision = prec)
b = im.gaussblur(sigma, min_ampl = 0.2, precision = prec)
a_point = a.getpoint(25, 50)
b_point = b.getpoint(25, 50)
self.assertAlmostEqualObjects(a_point, b_point, places = 1)
def test_sharpen(self):
for im in self.all_images:
for fmt in noncomplex_formats:
for radius in range(1, 7):
im = im.cast(fmt)
if im.bands == 3:
im = im.copy(interpretation = Vips.Interpretation.SRGB)
sharp = im.sharpen(radius = radius)
# hard to test much more than this
self.assertEqual(im.width, sharp.width)
self.assertEqual(im.height, sharp.height)
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if __name__ == '__main__':
unittest.main()