pytorch_13_pytorch 中tensor，numpy，PIL的转换

PIL:使用Python自带图像处理库读取出来的图片格式
numpy：使用Python-opencv库读取出来的图片格式
tensor：pytorch中训练时所采取的向量格式

import torch
import torchvision.transforms as transforms　

PIL  to Tensor

 def PIL2tensor(img):
     loader = transforms.Compose([
         transforms.ToTensor()
     ])
     image = loader(img).unsqueeze(0)
     return image.to(torch.device,torch.float)

Tensor to PIL

 def tensor2PIL(tensor): # 将tensor-> PIL
     unloader = transforms.ToPILImage()
     image = tensor.cpu().clone()
     image = image.squeeze(0)
     image = unloader(image)
     return image

Tensor to numpy

 def tensor2numpy(tensor):
     img = tensor.mul(255).byte()
     img = img.cpu().numpy().squeeze(0).tranpose((1,2,0))
     return img

numpy to tensor

    if isinstance(pic,np.ndarray):
        img = torch.from_numpy(pic.transpose((2,0,1)))
        return img.float().div(255)