DataLoader and letterbox() error.

[veeramallirajesh]

I have cloned the repository and followed the instructions exactly the way they are. When I am trying to train the model there is a weird error in DataLoader and letterbox() methods. Please help me to fix this error. The detailed error message is:

File "train.py", line 334, in train dataloader=testloader) File "/home/teraki/Desktop/rajesh/YoloV3-Custom-Object-Detection-master/test.py", line 72, in test for batch_i, (imgs, targets, paths, shapes) in enumerate(tqdm(dataloader, desc=s)): File "/home/teraki/Desktop/rajesh/yolo_env/lib/python3.6/site-packages/tqdm/std.py", line 1129, in iter for obj in iterable: File "/home/teraki/Desktop/rajesh/yolo_env/lib/python3.6/site-packages/torch/utils/data/dataloader.py", line 345, in next data = self._next_data() File "/home/teraki/Desktop/rajesh/yolo_env/lib/python3.6/site-packages/torch/utils/data/dataloader.py", line 856, in _next_data return self._process_data(data) File "/home/teraki/Desktop/rajesh/yolo_env/lib/python3.6/site-packages/torch/utils/data/dataloader.py", line 881, in _process_data data.reraise() File "/home/teraki/Desktop/rajesh/yolo_env/lib/python3.6/site-packages/torch/_utils.py", line 395, in reraise raise self.exc_type(msg) cv2.error: Caught error in DataLoader worker process 0. Original Traceback (most recent call last): File "/home/teraki/Desktop/rajesh/yolo_env/lib/python3.6/site-packages/torch/utils/data/_utils/worker.py", line 178, in _worker_loop data = fetcher.fetch(index) File "/home/teraki/Desktop/rajesh/yolo_env/lib/python3.6/site-packages/torch/utils/data/_utils/fetch.py", line 44, in fetch data = [self.dataset[idx] for idx in possibly_batched_index] File "/home/teraki/Desktop/rajesh/yolo_env/lib/python3.6/site-packages/torch/utils/data/_utils/fetch.py", line 44, in data = [self.dataset[idx] for idx in possibly_batched_index] File "/home/teraki/Desktop/rajesh/YoloV3-Custom-Object-Detection-master/utils/datasets.py", line 435, in getitem img, ratio, pad = letterbox(img, shape, auto=False, scaleup=self.augment) File "/home/teraki/Desktop/rajesh/YoloV3-Custom-Object-Detection-master/utils/datasets.py", line 633, in letterbox img = cv2.copyMakeBorder(img, top, bottom, left, right, cv2.BORDER_CONSTANT, value=color) # add border cv2.error: OpenCV(4.2.0) /io/opencv/modules/core/src/copy.cpp:1421: error: (-215:Assertion failed) top >= 0 && bottom >= 0 && left >= 0 && right >= 0 && _src.dims() <= 2 in function 'copyMakeBorder'