将tensor张量转换成图片格式并保存
这是一个工具包,功能:反向操作transforms.Normalize和transforms.ToTensor函数,将tensor格式的图片转换成.jpg、.png格式的图片import torchimport numpy as npfrom PIL import Imageimport torchvision.transforms as transformsdef transform_conve
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这是一个工具包,功能:反向操作transforms.Normalize和transforms.ToTensor函数,将tensor格式的图片转换成.jpg、.png格式的图片
(注:这里是我原始的写法,但是是存在着一些改进空间的【如评论区所言,会改变img_tensor的内容,但我这边就暂时保持原样了,详细的改进方法可见评论区】【感谢评论区大佬!】)
import torch
import numpy as np
from PIL import Image
import torchvision.transforms as transforms
def transform_convert(img_tensor, transform):
"""
param img_tensor: tensor
param transforms: torchvision.transforms
"""
if 'Normalize' in str(transform):
normal_transform = list(filter(lambda x: isinstance(x, transforms.Normalize), transform.transforms))
mean = torch.tensor(normal_transform[0].mean, dtype=img_tensor.dtype, device=img_tensor.device)
std = torch.tensor(normal_transform[0].std, dtype=img_tensor.dtype, device=img_tensor.device)
img_tensor.mul_(std[:,None,None]).add_(mean[:,None,None])
img_tensor = img_tensor.transpose(0,2).transpose(0,1) # C x H x W ---> H x W x C
if 'ToTensor' in str(transform) or img_tensor.max() < 1:
img_tensor = img_tensor.detach().numpy()*255
if isinstance(img_tensor, torch.Tensor):
img_tensor = img_tensor.numpy()
if img_tensor.shape[2] == 3:
img = Image.fromarray(img_tensor.astype('uint8')).convert('RGB')
elif img_tensor.shape[2] == 1:
img = Image.fromarray(img_tensor.astype('uint8')).squeeze()
else:
raise Exception("Invalid img shape, expected 1 or 3 in axis 2, but got {}!".format(img_tensor.shape[2]))
return img
代码示例
import matplotlib.pyplot as plt
img = Image.open('./lena.jpg')
ToTensor_transform = transforms.Compose([transforms.ToTensor()])
img_tensor = ToTensor_transform(img)
img = transform_convert(img_tensor, ToTensor_transform)
plt.imshow(img)
plt.savefig('./lenaa.png')
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