[Dataset Issue] kitti: Bounding boxes for objects_type are vertically flipped.

[nsthorat]

Bounding boxes for the kitti dataset are vertically flipped. This is a bug with the TensorFlow datasets implementation.

See: https://knowyourdata-tfds.withgoogle.google.com/#dataset=kitti&tab=ITEM&draw=kyd/kitti/objects_type,bbox,bbox&item=000079.png

See the BBoxFeature documentation on TensorFlow datasets: https://www.tensorflow.org/datasets/api_docs/python/tfds/features/BBoxFeature

This states:

bbox: tf.Tensor of type tf.float32 and shape [4,] which contains the normalized coordinates of the bounding box [ymin, xmin, ymax, xmax]