File size: 4,439 Bytes
1a79cb6
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
import cv2
import numpy as np
import scipy.sparse

def mask_from_points(size, points):
  """ Create a mask of supplied size from supplied points
  :param size: tuple of output mask size
  :param points: array of [x, y] points
  :returns: mask of values 0 and 255 where
            255 indicates the convex hull containing the points
  """
  radius = 10  # kernel size
  kernel = np.ones((radius, radius), np.uint8)

  mask = np.zeros(size, np.uint8)
  cv2.fillConvexPoly(mask, cv2.convexHull(points), 255)
  mask = cv2.erode(mask, kernel)

  return mask

def overlay_image(foreground_image, mask, background_image):
  """ Overlay foreground image onto the background given a mask
  :param foreground_image: foreground image points
  :param mask: [0-255] values in mask
  :param background_image: background image points
  :returns: image with foreground where mask > 0 overlaid on background image
  """
  foreground_pixels = mask > 0
  background_image[..., :3][foreground_pixels] = foreground_image[..., :3][foreground_pixels]
  return background_image

def apply_mask(img, mask):
  """ Apply mask to supplied image
  :param img: max 3 channel image
  :param mask: [0-255] values in mask
  :returns: new image with mask applied
  """
  masked_img = np.copy(img)
  num_channels = 3
  for c in range(num_channels):
    masked_img[..., c] = img[..., c] * (mask / 255)

  return masked_img

def weighted_average(img1, img2, percent=0.5):
  if percent <= 0:
    return img2
  elif percent >= 1:
    return img1
  else:
    return cv2.addWeighted(img1, percent, img2, 1-percent, 0)

def alpha_feathering(src_img, dest_img, img_mask, blur_radius=15):
  mask = cv2.blur(img_mask, (blur_radius, blur_radius))
  mask = mask / 255.0

  result_img = np.empty(src_img.shape, np.uint8)
  for i in range(3):
    result_img[..., i] = src_img[..., i] * mask + dest_img[..., i] * (1-mask)

  return result_img

def poisson_blend(img_source, dest_img, img_mask, offset=(0, 0)):
  # http://opencv.jp/opencv2-x-samples/poisson-blending
  img_target = np.copy(dest_img)
  import pyamg
  # compute regions to be blended
  region_source = (
    max(-offset[0], 0),
    max(-offset[1], 0),
    min(img_target.shape[0] - offset[0], img_source.shape[0]),
    min(img_target.shape[1] - offset[1], img_source.shape[1]))
  region_target = (
    max(offset[0], 0),
    max(offset[1], 0),
    min(img_target.shape[0], img_source.shape[0] + offset[0]),
    min(img_target.shape[1], img_source.shape[1] + offset[1]))
  region_size = (region_source[2] - region_source[0],
                 region_source[3] - region_source[1])

  # clip and normalize mask image
  img_mask = img_mask[region_source[0]:region_source[2],
                      region_source[1]:region_source[3]]

  # create coefficient matrix
  coff_mat = scipy.sparse.identity(np.prod(region_size), format='lil')
  for y in range(region_size[0]):
    for x in range(region_size[1]):
      if img_mask[y, x]:
        index = x + y * region_size[1]
        coff_mat[index, index] = 4
        if index + 1 < np.prod(region_size):
          coff_mat[index, index + 1] = -1
        if index - 1 >= 0:
          coff_mat[index, index - 1] = -1
        if index + region_size[1] < np.prod(region_size):
          coff_mat[index, index + region_size[1]] = -1
        if index - region_size[1] >= 0:
          coff_mat[index, index - region_size[1]] = -1
  coff_mat = coff_mat.tocsr()

  # create poisson matrix for b
  poisson_mat = pyamg.gallery.poisson(img_mask.shape)
  # for each layer (ex. RGB)
  for num_layer in range(img_target.shape[2]):
    # get subimages
    t = img_target[region_target[0]:region_target[2],
                   region_target[1]:region_target[3], num_layer]
    s = img_source[region_source[0]:region_source[2],
                   region_source[1]:region_source[3], num_layer]
    t = t.flatten()
    s = s.flatten()

    # create b
    b = poisson_mat * s
    for y in range(region_size[0]):
      for x in range(region_size[1]):
        if not img_mask[y, x]:
          index = x + y * region_size[1]
          b[index] = t[index]

    # solve Ax = b
    x = pyamg.solve(coff_mat, b, verb=False, tol=1e-10)

    # assign x to target image
    x = np.reshape(x, region_size)
    x[x > 255] = 255
    x[x < 0] = 0
    x = np.array(x, img_target.dtype)
    img_target[region_target[0]:region_target[2],
               region_target[1]:region_target[3], num_layer] = x

  return img_target