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comparison transformations/slant.py @ 34:e61a46996db6

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first commit, the module has been tested with testmod.py, it has no timing
author ychherawala@smets-w04
date Tue, 02 Feb 2010 10:00:03 -0500
parents
children e05715e4554d
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33:6d432a5010a2 34:e61a46996db6
1 #!/usr/bin/python
2 # coding: utf-8
3
4 '''
5 this module add a slant effect to the image.
6
7 To obtain the slant effect, each row of the array is shifted proportionately by a step
8 controlled by the complexity.
9
10 '''
11
12 import numpy
13
14
15 class Slant():
16 def __init__(self, complexity=1):
17 #---------- private attributes
18 self.direction = 1
19 self.angle = 0
20
21 #---------- generation parameters
22 self.regenerate_parameters(complexity)
23 #------------------------------------------------
24
25 def _get_current_parameters(self):
26 return [self.angle, self.direction]
27
28 def get_settings_names(self):
29 return ['angle', 'direction']
30
31 def regenerate_parameters(self, complexity):
32 self.angle = numpy.random.uniform(0.0, complexity)
33 P = numpy.random.uniform()
34 self.direction = 1;
35 if P < 0.5:
36 self.direction = -1;
37 return self._get_current_parameters()
38
39
40 def transform_image(self,image):
41 if self.angle == 0:
42 return image
43
44 ysize, xsize = image.shape
45 slant = self.direction*self.angle
46
47 output = image.copy()
48
49 # shift all the rows
50 for i in range(ysize):
51 line = image[i]
52 delta = round((i*slant)) % xsize
53 line1 = line[:xsize-delta]
54 line2 = line[xsize-delta:xsize]
55
56 output[i][delta:xsize] = line1
57 output[i][0:delta] = line2
58
59
60 #correction to center the image
61 correction = (self.direction)*round(self.angle*ysize/2)
62 correction = (xsize - correction) % xsize
63
64 # center the region
65 line1 = output[0:ysize,0:xsize-correction].copy()
66 line2 = output[0:ysize,xsize-correction:xsize].copy()
67 output[0:ysize,correction:xsize] = line1
68 output[0:ysize,0:correction] = line2
69
70
71 return output
72
73
74 # Test function
75 def test_slant():
76 img_name = "3.png"
77 dest_img_name = "slanted.png"
78 im = Image.open(img_name,)
79 im = im.convert("L")
80 image = numpy.asarray(im)
81
82
83 slant = Slant()
84 slant.regenerate_parameters(1)
85 image = slant.transform_image(image)
86
87 im = Image.fromarray(image.astype('uint8'), "L")
88 im.save(dest_img_name)
89
90 # Test
91 if __name__ == '__main__':
92 import sys, os, fnmatch
93 import Image
94
95 test_slant()
96