error: OpenCV(4.5.5) /io/opencv/modules/imgproc/src/color.cpp:182: error: (-215:Assertion failed) !_src.empty() in function 'cvtColor'

[sachinkmohan]

I am trying to run the below block and got this error

scores = model.evaluate_generator(test_dataloader)

print("Loss: {:.5}".format(scores[0]))
for metric, value in zip(metrics, scores[1:]):
    print("mean {}: {:.5}".format(metric.__name__, value))

Error trace

---------------------------------------------------------------------------
error                                     Traceback (most recent call last)
<ipython-input-23-085d0e8f0f9f> in <module>
----> 1 scores = model.evaluate_generator(test_dataloader)
      2 
      3 print("Loss: {:.5}".format(scores[0]))
      4 for metric, value in zip(metrics, scores[1:]):
      5     print("mean {}: {:.5}".format(metric.__name__, value))

~/anaconda2/envs/mltf115_2/lib/python3.6/site-packages/keras/legacy/interfaces.py in wrapper(*args, **kwargs)
     89                 warnings.warn('Update your `' + object_name + '` call to the ' +
     90                               'Keras 2 API: ' + signature, stacklevel=2)
---> 91             return func(*args, **kwargs)
     92         wrapper._original_function = func
     93         return wrapper

~/anaconda2/envs/mltf115_2/lib/python3.6/site-packages/keras/engine/training.py in evaluate_generator(self, generator, steps, callbacks, max_queue_size, workers, use_multiprocessing, verbose)
   1789             workers=workers,
   1790             use_multiprocessing=use_multiprocessing,
-> 1791             verbose=verbose)
   1792 
   1793     @interfaces.legacy_generator_methods_support

~/anaconda2/envs/mltf115_2/lib/python3.6/site-packages/keras/engine/training_generator.py in evaluate_generator(model, generator, steps, callbacks, max_queue_size, workers, use_multiprocessing, verbose)
    363 
    364         while steps_done < steps:
--> 365             generator_output = next(output_generator)
    366             if not hasattr(generator_output, '__len__'):
    367                 raise ValueError('Output of generator should be a tuple '

~/anaconda2/envs/mltf115_2/lib/python3.6/site-packages/keras/utils/data_utils.py in get(self)
    623         except Exception:
    624             self.stop()
--> 625             six.reraise(*sys.exc_info())
    626 
    627 

~/anaconda2/envs/mltf115_2/lib/python3.6/site-packages/six.py in reraise(tp, value, tb)
    701             if value.__traceback__ is not tb:
    702                 raise value.with_traceback(tb)
--> 703             raise value
    704         finally:
    705             value = None

~/anaconda2/envs/mltf115_2/lib/python3.6/site-packages/keras/utils/data_utils.py in get(self)
    608                 try:
    609                     future = self.queue.get(block=True)
--> 610                     inputs = future.get(timeout=30)
    611                 except mp.TimeoutError:
    612                     idx = future.idx

~/anaconda2/envs/mltf115_2/lib/python3.6/multiprocessing/pool.py in get(self, timeout)
    642             return self._value
    643         else:
--> 644             raise self._value
    645 
    646     def _set(self, i, obj):

~/anaconda2/envs/mltf115_2/lib/python3.6/multiprocessing/pool.py in worker(inqueue, outqueue, initializer, initargs, maxtasks, wrap_exception)
    117         job, i, func, args, kwds = task
    118         try:
--> 119             result = (True, func(*args, **kwds))
    120         except Exception as e:
    121             if wrap_exception and func is not _helper_reraises_exception:

~/anaconda2/envs/mltf115_2/lib/python3.6/site-packages/keras/utils/data_utils.py in get_index(uid, i)
    404         The value at index `i`.
    405     """
--> 406     return _SHARED_SEQUENCES[uid][i]
    407 
    408 

<ipython-input-4-f15eaa6c897e> in __getitem__(self, i)
    115         data = []
    116         for j in range(start, stop):
--> 117             data.append(self.dataset[j])
    118 
    119         # transpose list of lists

<ipython-input-4-f15eaa6c897e> in __getitem__(self, i)
     63         # read data
     64         image = cv2.imread(self.images_fps[i])
---> 65         image = cv2.cvtColor(image, cv2.COLOR_BGR2RGB)
     66         mask = cv2.imread(self.masks_fps[i], 0)
     67 

error: OpenCV(4.5.5) /io/opencv/modules/imgproc/src/color.cpp:182: error: (-215:Assertion failed) !_src.empty() in function 'cvtColor'

Can you please help?

P.S - I trained for just one epoch, to do a test on this repository.