imread - FileNotFoundError: No such file:

Question

I created a DataGenerator with Sequence class.

import tensorflow.keras as keras
from skimage.io import imread
from skimage.transform import resize
import numpy as np
import math
from tensorflow.keras.utils import Sequence

# Here, `x_set` is list of path to the images
# and `y_set` are the associated classes.

class DataGenerator(Sequence):

    def __init__(self, x_set, y_set, batch_size):
        self.x, self.y = x_set, y_set
        self.batch_size = batch_size

    def __len__(self):
        return math.ceil(len(self.x) / self.batch_size)

    def __getitem__(self, idx):
        batch_x = self.x[idx * self.batch_size:(idx + 1) *
        self.batch_size]
        batch_y = self.y[idx * self.batch_size:(idx + 1) *
        self.batch_size]

        return np.array([
            resize(imread(file_name), (224, 224))
               for file_name in batch_x]), np.array(batch_y)

Then, I applied this to my training and validation data. X_train is a list of strings which contains the image paths to the training data. y_train are onehotencoded labels of the training data. The same for validation data. I applied the DataGenerator to the training and validation data:

training_generator = DataGenerator(X_train, y_train, batch_size=32)
validation_generator = DataGenerator(X_val, y_val, batch_size=32)

Afterwards I used the fit_generator method to run a model:

model.fit_generator(generator=training_generator,
                    validation_data=validation_generator,
                    steps_per_epoch = num_train_samples // 32,
                    validation_steps = num_val_samples // 32,
                    epochs = 10,
                    use_multiprocessing=True,
                    workers=2)

And got the following error:

---------------------------------------------------------------------------
FileNotFoundError                         Traceback (most recent call last)
<ipython-input-79-f43ade94ee10> in <module>()
      5                     epochs = 10,
      6                     use_multiprocessing=True,
----> 7                     workers=2)

16 frames
/usr/local/lib/python3.6/dist-packages/imageio/core/request.py in _parse_uri(self, uri)
    271                 # Reading: check that the file exists (but is allowed a dir)
    272                 if not os.path.exists(fn):
--> 273                     raise FileNotFoundError("No such file: '%s'" % fn)
    274             else:
    275                 # Writing: check that the directory to write to does exist

FileNotFoundError: No such file: 'path/to/images/1_1.png'

It seems to me that the imread method does not find the file. I checked the image path and it is correct.

Does anyone know what I should change in the program?

Answer 1

Start checking the x_set variable (in the instantiation this translates to X_train): print out a small slice of this list of image paths e.g.

print(f"{X_train[:2] = }"),

then start checking one of these image paths if it exists, and if it is in the same path that you are pointing to from the Python script.