python - TypeError:图片应为PIL图像或ndarray。得到了

Question

我想使用Open CV拆分图像，然后将其馈送到PyTorch模型以计算每个图像中的对象。运行代码时出现以下错误消息:TypeError:图片应为PIL图像或ndarray。有

import os

import numpy as np
import torch
from PIL import Image
from torch.utils.data import Dataset
from torchvision import transforms, utils
#from torchvision.transforms import Grayscalei
import pandas as pd
import pdb
import cv2

class CellsDataset(Dataset):
    # a very simple dataset

    def __init__(self, root_dir, transform=None, return_filenames=False):
        self.root = root_dir
        self.transform = transform
        self.return_filenames = return_filenames
        self.files = [os.path.join(self.root,filename) for filename in os.listdir(self.root)]
        self.files = [path for path in self.files
                      if os.path.isfile(path) and os.path.splitext(path)[1]=='.png']

    def __len__(self):
        return len(self.files)

    def __getitem__(self, idx):
        path = self.files[idx]
        sample = Image.open(path)        

        sample = cv2.imread(path)
        b,g,r=cv2.split(sample)
        sample=cv2.imwrite('sample.png', g)


        #transform3 = Grayscale(num_output_channels=3)
        #sample = transform3(sample) # convert to a 3 channel grayscale, as it needs to be 3 channel.
        if self.transform:
            sample = self.transform(sample)

        if self.return_filenames:
            return sample, path
        else:
            return sample

Answer 1

变量sample被重新分配给此行中cv2.imwrite返回的内容:

sample=cv2.imwrite('sample.png', g)

那用其他东西代替了你的ndarray。
尝试用简单的 cv2.imwrite('sample.png', g)替换该行，而不将评估表达式的值分配给 sample。