比较与torchvision.transforms.ToTensor的功能差异
torchvision.transforms.ToTensor
class torchvision.transforms.ToTensor
mindspore.dataset.vision.ToTensor
class mindspore.dataset.vision.ToTensor(
output_type=np.float32
)
使用方式
PyTorch:将PIL类型的Image或numpy 数组转换为 torch中的Tensor, 输入的numpy数组通常是<H, W, C>格式且取值在[0, 255]范围,输出是<C, H, W>格式且取值在[0.0, 1.0]的torch Tensor。
MindSpore:输入为PIL类型的图像或<H, W, C>格式且取值在[0, 255]范围内的numpy数组,输出为[0.0, 1.0]范围内且具有<C, H, W>格式的numpy数组;等同于在原始输入图像上做了通道转换及像素值归一化两种操作。
代码示例
import numpy as np
from PIL import Image
from torchvision import transforms
from mindspore.dataset import py_transforms
import mindspore.dataset.vision as vision
# In MindSpore, ToTensor convert PIL Image into numpy array.
img_path = "/path/to/test/1.jpg"
img = Image.open(img_path)
to_tensor = vision.ToTensor()
img_data = to_tensor(img)
print("img_data type:", type(img_data))
print("img_data dtype:", img_data.dtype)
# Out:
#img_data type: <class 'numpy.ndarray'>
#img_data dtype: float32
# In torch, ToTensor transforms the input to tensor.
img_path = "/path/to/test/1.jpg"
image_transform = transforms.Compose([transforms.ToTensor()])
img = np.array(Image.open(img_path))
img_data = image_transform(img)
print(img_data.shape)
# Out:
# torch.Size([3, 2268, 4032])