标准化传递给torch.transforms.Compose函数的图像 [英] Normalizing images passed to torch.transforms.Compose function
问题描述
如何在PyTorch中找到要传递给transforms.Normalize函数的值?另外，在我的代码中，我应该准确地进行转换.进行归一化吗?
How to find the values to pass to the transforms.Normalize function in PyTorch? Also, where in my code, should I exactly do the transforms.Normalize?
由于标准化数据集是一项众所周知的任务，我希望应该有某种脚本可以自动执行此操作.至少我在PyTorch论坛上找不到它.
Since normalizing the dataset is a pretty well-known task, I was hoping there should be some sort of script for doing that automatically. At least I couldn't find it in PyTorch forum.
transformed_dataset = MothLandmarksDataset(csv_file='moth_gt.csv',
root_dir='.',
transform=transforms.Compose([
Rescale(256),
RandomCrop(224),
transforms.Normalize(mean = [ 0.485, 0.456, 0.406 ],
std = [ 0.229, 0.224, 0.225 ]),
ToTensor()
]))
for i in range(len(transformed_dataset)):
sample = transformed_dataset[i]
print(i, sample['image'].size(), sample['landmarks'].size())
if i == 3:
break
我知道这些当前值与我的数据集无关，与ImageNet无关，但是使用它们实际上会出现错误:
I know these current values don't pertain to my dataset and pertain to ImageNet but using them I actually get an error:
TypeError Traceback (most recent call last)
<ipython-input-81-eb8dc46e0284> in <module>
10
11 for i in range(len(transformed_dataset)):
---> 12 sample = transformed_dataset[i]
13
14 print(i, sample['image'].size(), sample['landmarks'].size())
<ipython-input-48-9d04158922fb> in __getitem__(self, idx)
30
31 if self.transform:
---> 32 sample = self.transform(sample)
33
34 return sample
~/anaconda3/lib/python3.7/site-packages/torchvision/transforms/transforms.py in __call__(self, img)
59 def __call__(self, img):
60 for t in self.transforms:
---> 61 img = t(img)
62 return img
63
~/anaconda3/lib/python3.7/site-packages/torchvision/transforms/transforms.py in __call__(self, tensor)
210 Tensor: Normalized Tensor image.
211 """
--> 212 return F.normalize(tensor, self.mean, self.std, self.inplace)
213
214 def __repr__(self):
~/anaconda3/lib/python3.7/site-packages/torchvision/transforms/functional.py in normalize(tensor, mean, std, inplace)
278 """
279 if not torch.is_tensor(tensor):
--> 280 raise TypeError('tensor should be a torch tensor. Got {}.'.format(type(tensor)))
281
282 if tensor.ndimension() != 3:
TypeError: tensor should be a torch tensor. Got <class 'dict'>.
所以基本上是三个问题:
So basically three questions:
- 如何为自己的自定义数据集找到与ImageNet mean和std中相似的值?
- 如何在这些地方传递这些值?我以为我应该在transforms.Compose方法中这样做，但是我可能错了.
- 我想我应该对整个数据集应用归一化，而不仅仅是训练集，对吗?
更新:
在这里尝试提供的解决方案对我不起作用:错误是:
<class 'dict'>
---------------------------------------------------------------------------
AttributeError Traceback (most recent call last)
<ipython-input-51-e8ba3c8718bb> in <module>
5 for data in dataloader:
6 print(type(data))
----> 7 batch_samples = data.size(0)
8
9 data.shape(0)
AttributeError: 'dict' object has no attribute 'size'
这是打印(数据)结果:
this is print(data) result:
{'image': tensor([[[[0.2961, 0.2941, 0.2941, ..., 0.2460, 0.2456, 0.2431],
[0.2953, 0.2977, 0.2980, ..., 0.2442, 0.2431, 0.2431],
[0.2941, 0.2941, 0.2980, ..., 0.2471, 0.2471, 0.2448],
...,
[0.3216, 0.3216, 0.3216, ..., 0.2482, 0.2471, 0.2471],
[0.3216, 0.3241, 0.3253, ..., 0.2471, 0.2471, 0.2450],
[0.3216, 0.3216, 0.3216, ..., 0.2471, 0.2452, 0.2431]],
[[0.2961, 0.2941, 0.2941, ..., 0.2460, 0.2456, 0.2431],
[0.2953, 0.2977, 0.2980, ..., 0.2442, 0.2431, 0.2431],
[0.2941, 0.2941, 0.2980, ..., 0.2471, 0.2471, 0.2448],
...,
[0.3216, 0.3216, 0.3216, ..., 0.2482, 0.2471, 0.2471],
[0.3216, 0.3241, 0.3253, ..., 0.2471, 0.2471, 0.2450],
[0.3216, 0.3216, 0.3216, ..., 0.2471, 0.2452, 0.2431]],
[[0.2961, 0.2941, 0.2941, ..., 0.2460, 0.2456, 0.2431],
[0.2953, 0.2977, 0.2980, ..., 0.2442, 0.2431, 0.2431],
[0.2941, 0.2941, 0.2980, ..., 0.2471, 0.2471, 0.2448],
...,
[0.3216, 0.3216, 0.3216, ..., 0.2482, 0.2471, 0.2471],
[0.3216, 0.3241, 0.3253, ..., 0.2471, 0.2471, 0.2450],
[0.3216, 0.3216, 0.3216, ..., 0.2471, 0.2452, 0.2431]]],
[[[0.3059, 0.3093, 0.3140, ..., 0.3373, 0.3363, 0.3345],
[0.3059, 0.3093, 0.3165, ..., 0.3412, 0.3389, 0.3373],
[0.3098, 0.3131, 0.3176, ..., 0.3450, 0.3412, 0.3412],
...,
[0.2931, 0.2966, 0.2931, ..., 0.2549, 0.2539, 0.2510],
[0.2902, 0.2902, 0.2902, ..., 0.2510, 0.2510, 0.2502],
[0.2864, 0.2900, 0.2863, ..., 0.2510, 0.2510, 0.2510]],
[[0.3059, 0.3093, 0.3140, ..., 0.3373, 0.3363, 0.3345],
[0.3059, 0.3093, 0.3165, ..., 0.3412, 0.3389, 0.3373],
[0.3098, 0.3131, 0.3176, ..., 0.3450, 0.3412, 0.3412],
...,
[0.2931, 0.2966, 0.2931, ..., 0.2549, 0.2539, 0.2510],
[0.2902, 0.2902, 0.2902, ..., 0.2510, 0.2510, 0.2502],
[0.2864, 0.2900, 0.2863, ..., 0.2510, 0.2510, 0.2510]],
[[0.3059, 0.3093, 0.3140, ..., 0.3373, 0.3363, 0.3345],
[0.3059, 0.3093, 0.3165, ..., 0.3412, 0.3389, 0.3373],
[0.3098, 0.3131, 0.3176, ..., 0.3450, 0.3412, 0.3412],
...,
[0.2931, 0.2966, 0.2931, ..., 0.2549, 0.2539, 0.2510],
[0.2902, 0.2902, 0.2902, ..., 0.2510, 0.2510, 0.2502],
[0.2864, 0.2900, 0.2863, ..., 0.2510, 0.2510, 0.2510]]],
[[[0.2979, 0.2980, 0.3015, ..., 0.2825, 0.2784, 0.2784],
[0.2980, 0.2980, 0.2980, ..., 0.2830, 0.2764, 0.2795],
[0.2980, 0.2980, 0.3012, ..., 0.2827, 0.2814, 0.2797],
...,
[0.3282, 0.3293, 0.3294, ..., 0.2238, 0.2235, 0.2235],
[0.3255, 0.3255, 0.3255, ..., 0.2240, 0.2235, 0.2229],
[0.3225, 0.3255, 0.3255, ..., 0.2216, 0.2235, 0.2223]],
[[0.2979, 0.2980, 0.3015, ..., 0.2825, 0.2784, 0.2784],
[0.2980, 0.2980, 0.2980, ..., 0.2830, 0.2764, 0.2795],
[0.2980, 0.2980, 0.3012, ..., 0.2827, 0.2814, 0.2797],
...,
[0.3282, 0.3293, 0.3294, ..., 0.2238, 0.2235, 0.2235],
[0.3255, 0.3255, 0.3255, ..., 0.2240, 0.2235, 0.2229],
[0.3225, 0.3255, 0.3255, ..., 0.2216, 0.2235, 0.2223]],
[[0.2979, 0.2980, 0.3015, ..., 0.2825, 0.2784, 0.2784],
[0.2980, 0.2980, 0.2980, ..., 0.2830, 0.2764, 0.2795],
[0.2980, 0.2980, 0.3012, ..., 0.2827, 0.2814, 0.2797],
...,
[0.3282, 0.3293, 0.3294, ..., 0.2238, 0.2235, 0.2235],
[0.3255, 0.3255, 0.3255, ..., 0.2240, 0.2235, 0.2229],
[0.3225, 0.3255, 0.3255, ..., 0.2216, 0.2235, 0.2223]]]],
dtype=torch.float64), 'landmarks': tensor([[[160.2964, 98.7339],
[223.0788, 72.5067],
[ 82.4163, 70.3733],
[152.3213, 137.7867]],
[[198.3194, 74.4341],
[273.7188, 118.7733],
[117.7113, 80.8000],
[182.0750, 107.2533]],
[[137.4789, 92.8523],
[174.9463, 40.3467],
[ 57.3013, 59.1200],
[129.3375, 131.6533]]], dtype=torch.float64)}
dataloader = DataLoader(transformed_dataset, batch_size=3,
shuffle=True, num_workers=4)
和
transformed_dataset = MothLandmarksDataset(csv_file='moth_gt.csv',
root_dir='.',
transform=transforms.Compose(
[
Rescale(256),
RandomCrop(224),
ToTensor()#,
##transforms.Normalize(mean = [ 0.485, 0.456, 0.406 ],
## std = [ 0.229, 0.224, 0.225 ])
]
)
)
和
class MothLandmarksDataset(Dataset):
"""Face Landmarks dataset."""
def __init__(self, csv_file, root_dir, transform=None):
"""
Args:
csv_file (string): Path to the csv file with annotations.
root_dir (string): Directory with all the images.
transform (callable, optional): Optional transform to be applied
on a sample.
"""
self.landmarks_frame = pd.read_csv(csv_file)
self.root_dir = root_dir
self.transform = transform
def __len__(self):
return len(self.landmarks_frame)
def __getitem__(self, idx):
if torch.is_tensor(idx):
idx = idx.tolist()
img_name = os.path.join(self.root_dir, self.landmarks_frame.iloc[idx, 0])
image = io.imread(img_name)
landmarks = self.landmarks_frame.iloc[idx, 1:]
landmarks = np.array([landmarks])
landmarks = landmarks.astype('float').reshape(-1, 2)
sample = {'image': image, 'landmarks': landmarks}
if self.transform:
sample = self.transform(sample)
return sample
推荐答案
源代码错误
如何传递这些值以及在哪里传递?我想我应该在transforms.Compose方法，但我可能是错的.
How to pass these values and where? I assume I should do it in transforms.Compose method but I might be wrong.
在 MothLandmarksDataset 中，当您尝试将 Dict ( sample )传递到 torchvision时，这也就不足为奇了.转换，需要 torch.Tensor 或 PIL.Image 作为输入.确切地说是这样:
In MothLandmarksDataset it is no wonder it is not working as you are trying to pass Dict (sample) to torchvision.transforms which require either torch.Tensor or PIL.Image as input. here to be exact:
sample = {'image': image, 'landmarks': landmarks}
if self.transform:
sample = self.transform(sample)
您可以将样本[图像"] 传递到其中，尽管不应该.仅将此操作应用于 sample ["image"] 会破坏其与 landmarks 的关系.您应该追求的是类似 albumentations 库(请参见此处)，可以用相同的方式转换 image 和 landmarks 以保留它们之间的关系.
You could pass sample["image"] into it although you shouldn't. Applying this operation only to sample["image"] would break its relation to landmarks. What you should be after is something like albumentations library (see here) which can transform image and landmarks in the same way to preserve their relations.
在 torchvision 中也没有 Rescale 转换，也许您的意思是
Also there is no Rescale transform in torchvision, maybe you meant Resize?
提供的代码很好，，但是您必须像这样将数据解压缩到 torch.Tensor 中.
Provided code is fine, but you have to unpack your data into torch.Tensor like this:
mean = 0.0
std = 0.0
nb_samples = 0.0
for data in dataloader:
images, landmarks = data["image"], data["landmarks"]
batch_samples = images.size(0)
images_data = images.view(batch_samples, images.size(1), -1)
mean += images_data.mean(2).sum(0)
std += images_data.std(2).sum(0)
nb_samples += batch_samples
mean /= nb_samples
std /= nb_samples
如何在哪里传递这些值?我想我应该在transforms.Compose方法，但我可能是错的.
How to pass these values and where? I assume I should do it in transforms.Compose method but I might be wrong.
这些值应传递给 torchvision.transforms.Normalize 仅应用于 sample ["images"] ，而不应用于 sample ["landmarks"] .
Those values should be passed to torchvision.transforms.Normalize applied only to sample["images"], not to sample["landmarks"].
我认为我应该将Normalize应用于我的整个数据集，而不仅仅是训练集，对吗?
I assume I should apply Normalize to my entire dataset not just the training set, am I right?
您应该在整个训练数据集中计算归一化值，并将这些计算出的值也应用于验证和测试.
You should calculate normalization values across training dataset and apply those calculated values to validation and test as well.
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