Customer dataset error: ValueError: not enough values to unpack (expected 3, got 2)

[JiayuanWang-JW]

Thanks for your fantastic work.

I encountered an issue when I changed the dataset to my own dataset. This error is not always present but sometimes happens when evaluating the model on val dataset.

I think the issue is my dataset includes empty mask which means this image does not include any object, only the background in the mask. The whole mask pixel value only has 255. But I am not sure.

Please let me know any suggestions about this issue. Thanks!