File size: 5,333 Bytes
8c9c9c7
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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
"""This script is to generate skin attention mask for Deep3DFaceRecon_pytorch
"""

import math
import numpy as np
import os
import cv2

class GMM:
    def __init__(self, dim, num, w, mu, cov, cov_det, cov_inv):
        self.dim = dim # feature dimension
        self.num = num # number of Gaussian components
        self.w = w # weights of Gaussian components (a list of scalars)
        self.mu= mu # mean of Gaussian components (a list of 1xdim vectors)
        self.cov = cov # covariance matrix of Gaussian components (a list of dimxdim matrices)
        self.cov_det = cov_det # pre-computed determinet of covariance matrices (a list of scalars)
        self.cov_inv = cov_inv # pre-computed inverse covariance matrices (a list of dimxdim matrices)

        self.factor = [0]*num
        for i in range(self.num):
            self.factor[i] = (2*math.pi)**(self.dim/2) * self.cov_det[i]**0.5
        
    def likelihood(self, data):
        assert(data.shape[1] == self.dim)
        N = data.shape[0]
        lh = np.zeros(N)

        for i in range(self.num):
            data_ = data - self.mu[i]

            tmp = np.matmul(data_,self.cov_inv[i]) * data_
            tmp = np.sum(tmp,axis=1)
            power = -0.5 * tmp

            p = np.array([math.exp(power[j]) for j in range(N)])
            p = p/self.factor[i]
            lh += p*self.w[i]
        
        return lh


def _rgb2ycbcr(rgb):
    m = np.array([[65.481, 128.553, 24.966],
                  [-37.797, -74.203, 112],
                  [112, -93.786, -18.214]])
    shape = rgb.shape
    rgb = rgb.reshape((shape[0] * shape[1], 3))
    ycbcr = np.dot(rgb, m.transpose() / 255.)
    ycbcr[:, 0] += 16.
    ycbcr[:, 1:] += 128.
    return ycbcr.reshape(shape)


def _bgr2ycbcr(bgr):
    rgb = bgr[..., ::-1]
    return _rgb2ycbcr(rgb)


gmm_skin_w = [0.24063933, 0.16365987, 0.26034665, 0.33535415]
gmm_skin_mu = [np.array([113.71862, 103.39613, 164.08226]),
                np.array([150.19858, 105.18467, 155.51428]),
                np.array([183.92976, 107.62468, 152.71820]),
                np.array([114.90524, 113.59782, 151.38217])]
gmm_skin_cov_det = [5692842.5, 5851930.5, 2329131., 1585971.]
gmm_skin_cov_inv = [np.array([[0.0019472069, 0.0020450759, -0.00060243998],[0.0020450759, 0.017700525, 0.0051420014],[-0.00060243998, 0.0051420014, 0.0081308950]]),
                    np.array([[0.0027110141, 0.0011036990, 0.0023122299],[0.0011036990, 0.010707724, 0.010742856],[0.0023122299, 0.010742856, 0.017481629]]),
                    np.array([[0.0048026871, 0.00022935172, 0.0077668377],[0.00022935172, 0.011729696, 0.0081661865],[0.0077668377, 0.0081661865, 0.025374353]]),
                    np.array([[0.0011989699, 0.0022453172, -0.0010748957],[0.0022453172, 0.047758564, 0.020332102],[-0.0010748957, 0.020332102, 0.024502251]])]

gmm_skin = GMM(3, 4, gmm_skin_w, gmm_skin_mu, [], gmm_skin_cov_det, gmm_skin_cov_inv)

gmm_nonskin_w = [0.12791070, 0.31130761, 0.34245777, 0.21832393]
gmm_nonskin_mu = [np.array([99.200851, 112.07533, 140.20602]),
                    np.array([110.91392, 125.52969, 130.19237]),
                    np.array([129.75864, 129.96107, 126.96808]),
                    np.array([112.29587, 128.85121, 129.05431])]
gmm_nonskin_cov_det = [458703648., 6466488., 90611376., 133097.63]
gmm_nonskin_cov_inv = [np.array([[0.00085371657, 0.00071197288, 0.00023958916],[0.00071197288, 0.0025935620, 0.00076557708],[0.00023958916, 0.00076557708, 0.0015042332]]),
                    np.array([[0.00024650150, 0.00045542428, 0.00015019422],[0.00045542428, 0.026412144, 0.018419769],[0.00015019422, 0.018419769, 0.037497383]]),
                    np.array([[0.00037054974, 0.00038146760, 0.00040408765],[0.00038146760, 0.0085505722, 0.0079136286],[0.00040408765, 0.0079136286, 0.010982352]]),
                    np.array([[0.00013709733, 0.00051228428, 0.00012777430],[0.00051228428, 0.28237113, 0.10528370],[0.00012777430, 0.10528370, 0.23468947]])]

gmm_nonskin = GMM(3, 4, gmm_nonskin_w, gmm_nonskin_mu, [], gmm_nonskin_cov_det, gmm_nonskin_cov_inv)

prior_skin = 0.8
prior_nonskin = 1 - prior_skin


# calculate skin attention mask
def skinmask(imbgr):
    im = _bgr2ycbcr(imbgr)

    data = im.reshape((-1,3))

    lh_skin = gmm_skin.likelihood(data)
    lh_nonskin = gmm_nonskin.likelihood(data)

    tmp1 = prior_skin * lh_skin
    tmp2 = prior_nonskin * lh_nonskin
    post_skin = tmp1 / (tmp1+tmp2) # posterior probability

    post_skin = post_skin.reshape((im.shape[0],im.shape[1]))

    post_skin = np.round(post_skin*255)
    post_skin = post_skin.astype(np.uint8)
    post_skin = np.tile(np.expand_dims(post_skin,2),[1,1,3]) # reshape to H*W*3

    return post_skin


def get_skin_mask(img_path):
    print('generating skin masks......')
    names = [i for i in sorted(os.listdir(
        img_path)) if 'jpg' in i or 'png' in i or 'jpeg' in i or 'PNG' in i]
    save_path = os.path.join(img_path, 'mask')
    if not os.path.isdir(save_path):
        os.makedirs(save_path)
    
    for i in range(0, len(names)):
        name = names[i]
        print('%05d' % (i), ' ', name)
        full_image_name = os.path.join(img_path, name)
        img = cv2.imread(full_image_name).astype(np.float32)
        skin_img = skinmask(img)
        cv2.imwrite(os.path.join(save_path, name), skin_img.astype(np.uint8))