|
| 1 | +import torch |
| 2 | +import torch.nn.functional as F |
| 3 | +from math import exp |
| 4 | +import numpy as np |
| 5 | + |
| 6 | +device = torch.device("cuda" if torch.cuda.is_available() else "cpu") |
| 7 | + |
| 8 | + |
| 9 | +def gaussian(window_size, sigma): |
| 10 | + gauss = torch.Tensor([exp(-(x - window_size//2)**2/float(2*sigma**2)) for x in range(window_size)]) |
| 11 | + return gauss/gauss.sum() |
| 12 | + |
| 13 | + |
| 14 | +def create_window(window_size, channel=1): |
| 15 | + _1D_window = gaussian(window_size, 1.5).unsqueeze(1) |
| 16 | + _2D_window = _1D_window.mm(_1D_window.t()).float().unsqueeze(0).unsqueeze(0).to(device) |
| 17 | + window = _2D_window.expand(channel, 1, window_size, window_size).contiguous() |
| 18 | + return window |
| 19 | + |
| 20 | + |
| 21 | +def create_window_3d(window_size, channel=1): |
| 22 | + _1D_window = gaussian(window_size, 1.5).unsqueeze(1) |
| 23 | + _2D_window = _1D_window.mm(_1D_window.t()) |
| 24 | + _3D_window = _2D_window.unsqueeze(2) @ (_1D_window.t()) |
| 25 | + window = _3D_window.expand(1, channel, window_size, window_size, window_size).contiguous().to(device) |
| 26 | + return window |
| 27 | + |
| 28 | + |
| 29 | +def ssim(img1, img2, window_size=11, window=None, size_average=True, full=False, val_range=None): |
| 30 | + # Value range can be different from 255. Other common ranges are 1 (sigmoid) and 2 (tanh). |
| 31 | + if val_range is None: |
| 32 | + if torch.max(img1) > 128: |
| 33 | + max_val = 255 |
| 34 | + else: |
| 35 | + max_val = 1 |
| 36 | + |
| 37 | + if torch.min(img1) < -0.5: |
| 38 | + min_val = -1 |
| 39 | + else: |
| 40 | + min_val = 0 |
| 41 | + L = max_val - min_val |
| 42 | + else: |
| 43 | + L = val_range |
| 44 | + |
| 45 | + padd = 0 |
| 46 | + (_, channel, height, width) = img1.size() |
| 47 | + if window is None: |
| 48 | + real_size = min(window_size, height, width) |
| 49 | + window = create_window(real_size, channel=channel).to(img1.device) |
| 50 | + |
| 51 | + # mu1 = F.conv2d(img1, window, padding=padd, groups=channel) |
| 52 | + # mu2 = F.conv2d(img2, window, padding=padd, groups=channel) |
| 53 | + mu1 = F.conv2d(F.pad(img1, (5, 5, 5, 5), mode='replicate'), window, padding=padd, groups=channel) |
| 54 | + mu2 = F.conv2d(F.pad(img2, (5, 5, 5, 5), mode='replicate'), window, padding=padd, groups=channel) |
| 55 | + |
| 56 | + mu1_sq = mu1.pow(2) |
| 57 | + mu2_sq = mu2.pow(2) |
| 58 | + mu1_mu2 = mu1 * mu2 |
| 59 | + |
| 60 | + sigma1_sq = F.conv2d(F.pad(img1 * img1, (5, 5, 5, 5), 'replicate'), window, padding=padd, groups=channel) - mu1_sq |
| 61 | + sigma2_sq = F.conv2d(F.pad(img2 * img2, (5, 5, 5, 5), 'replicate'), window, padding=padd, groups=channel) - mu2_sq |
| 62 | + sigma12 = F.conv2d(F.pad(img1 * img2, (5, 5, 5, 5), 'replicate'), window, padding=padd, groups=channel) - mu1_mu2 |
| 63 | + |
| 64 | + C1 = (0.01 * L) ** 2 |
| 65 | + C2 = (0.03 * L) ** 2 |
| 66 | + |
| 67 | + v1 = 2.0 * sigma12 + C2 |
| 68 | + v2 = sigma1_sq + sigma2_sq + C2 |
| 69 | + cs = torch.mean(v1 / v2) # contrast sensitivity |
| 70 | + |
| 71 | + ssim_map = ((2 * mu1_mu2 + C1) * v1) / ((mu1_sq + mu2_sq + C1) * v2) |
| 72 | + |
| 73 | + if size_average: |
| 74 | + ret = ssim_map.mean() |
| 75 | + else: |
| 76 | + ret = ssim_map.mean(1).mean(1).mean(1) |
| 77 | + |
| 78 | + if full: |
| 79 | + return ret, cs |
| 80 | + return ret |
| 81 | + |
| 82 | + |
| 83 | +def ssim_matlab(img1, img2, window_size=11, window=None, size_average=True, full=False, val_range=None): |
| 84 | + # Value range can be different from 255. Other common ranges are 1 (sigmoid) and 2 (tanh). |
| 85 | + if val_range is None: |
| 86 | + if torch.max(img1) > 128: |
| 87 | + max_val = 255 |
| 88 | + else: |
| 89 | + max_val = 1 |
| 90 | + |
| 91 | + if torch.min(img1) < -0.5: |
| 92 | + min_val = -1 |
| 93 | + else: |
| 94 | + min_val = 0 |
| 95 | + L = max_val - min_val |
| 96 | + else: |
| 97 | + L = val_range |
| 98 | + |
| 99 | + padd = 0 |
| 100 | + (_, _, height, width) = img1.size() |
| 101 | + if window is None: |
| 102 | + real_size = min(window_size, height, width) |
| 103 | + window = create_window_3d(real_size, channel=1).to(img1.device) |
| 104 | + # Channel is set to 1 since we consider color images as volumetric images |
| 105 | + |
| 106 | + img1 = img1.unsqueeze(1) |
| 107 | + img2 = img2.unsqueeze(1) |
| 108 | + |
| 109 | + mu1 = F.conv3d(F.pad(img1, (5, 5, 5, 5, 5, 5), mode='replicate'), window, padding=padd, groups=1) |
| 110 | + mu2 = F.conv3d(F.pad(img2, (5, 5, 5, 5, 5, 5), mode='replicate'), window, padding=padd, groups=1) |
| 111 | + |
| 112 | + mu1_sq = mu1.pow(2) |
| 113 | + mu2_sq = mu2.pow(2) |
| 114 | + mu1_mu2 = mu1 * mu2 |
| 115 | + |
| 116 | + sigma1_sq = F.conv3d(F.pad(img1 * img1, (5, 5, 5, 5, 5, 5), 'replicate'), window, padding=padd, groups=1) - mu1_sq |
| 117 | + sigma2_sq = F.conv3d(F.pad(img2 * img2, (5, 5, 5, 5, 5, 5), 'replicate'), window, padding=padd, groups=1) - mu2_sq |
| 118 | + sigma12 = F.conv3d(F.pad(img1 * img2, (5, 5, 5, 5, 5, 5), 'replicate'), window, padding=padd, groups=1) - mu1_mu2 |
| 119 | + |
| 120 | + C1 = (0.01 * L) ** 2 |
| 121 | + C2 = (0.03 * L) ** 2 |
| 122 | + |
| 123 | + v1 = 2.0 * sigma12 + C2 |
| 124 | + v2 = sigma1_sq + sigma2_sq + C2 |
| 125 | + cs = torch.mean(v1 / v2) # contrast sensitivity |
| 126 | + |
| 127 | + ssim_map = ((2 * mu1_mu2 + C1) * v1) / ((mu1_sq + mu2_sq + C1) * v2) |
| 128 | + |
| 129 | + if size_average: |
| 130 | + ret = ssim_map.mean() |
| 131 | + else: |
| 132 | + ret = ssim_map.mean(1).mean(1).mean(1) |
| 133 | + |
| 134 | + if full: |
| 135 | + return ret, cs |
| 136 | + return ret |
| 137 | + |
| 138 | + |
| 139 | +def msssim(img1, img2, window_size=11, size_average=True, val_range=None, normalize=False): |
| 140 | + device = img1.device |
| 141 | + weights = torch.FloatTensor([0.0448, 0.2856, 0.3001, 0.2363, 0.1333]).to(device) |
| 142 | + levels = weights.size()[0] |
| 143 | + mssim = [] |
| 144 | + mcs = [] |
| 145 | + for _ in range(levels): |
| 146 | + sim, cs = ssim(img1, img2, window_size=window_size, size_average=size_average, full=True, val_range=val_range) |
| 147 | + mssim.append(sim) |
| 148 | + mcs.append(cs) |
| 149 | + |
| 150 | + img1 = F.avg_pool2d(img1, (2, 2)) |
| 151 | + img2 = F.avg_pool2d(img2, (2, 2)) |
| 152 | + |
| 153 | + mssim = torch.stack(mssim) |
| 154 | + mcs = torch.stack(mcs) |
| 155 | + |
| 156 | + # Normalize (to avoid NaNs during training unstable models, not compliant with original definition) |
| 157 | + if normalize: |
| 158 | + mssim = (mssim + 1) / 2 |
| 159 | + mcs = (mcs + 1) / 2 |
| 160 | + |
| 161 | + pow1 = mcs ** weights |
| 162 | + pow2 = mssim ** weights |
| 163 | + # From Matlab implementation https://ece.uwaterloo.ca/~z70wang/research/iwssim/ |
| 164 | + output = torch.prod(pow1[:-1] * pow2[-1]) |
| 165 | + return output |
| 166 | + |
| 167 | + |
| 168 | +# Classes to re-use window |
| 169 | +class SSIM(torch.nn.Module): |
| 170 | + def __init__(self, window_size=11, size_average=True, val_range=None): |
| 171 | + super(SSIM, self).__init__() |
| 172 | + self.window_size = window_size |
| 173 | + self.size_average = size_average |
| 174 | + self.val_range = val_range |
| 175 | + |
| 176 | + # Assume 3 channel for SSIM |
| 177 | + self.channel = 3 |
| 178 | + self.window = create_window(window_size, channel=self.channel) |
| 179 | + |
| 180 | + def forward(self, img1, img2): |
| 181 | + (_, channel, _, _) = img1.size() |
| 182 | + |
| 183 | + if channel == self.channel and self.window.dtype == img1.dtype: |
| 184 | + window = self.window |
| 185 | + else: |
| 186 | + window = create_window(self.window_size, channel).to(img1.device).type(img1.dtype) |
| 187 | + self.window = window |
| 188 | + self.channel = channel |
| 189 | + |
| 190 | + _ssim = ssim(img1, img2, window=window, window_size=self.window_size, size_average=self.size_average) |
| 191 | + dssim = (1 - _ssim) / 2 |
| 192 | + return dssim |
| 193 | + |
| 194 | + |
| 195 | +class MSSSIM(torch.nn.Module): |
| 196 | + def __init__(self, window_size=11, size_average=True, channel=3): |
| 197 | + super(MSSSIM, self).__init__() |
| 198 | + self.window_size = window_size |
| 199 | + self.size_average = size_average |
| 200 | + self.channel = channel |
| 201 | + |
| 202 | + def forward(self, img1, img2): |
| 203 | + return msssim(img1, img2, window_size=self.window_size, size_average=self.size_average) |
0 commit comments