About annotation id

[Spritea]

Hi, I found that the annotation id starts with 0 in the csv2coco.py file:

prepare_detection_dataset/csv2coco.py

Line 29 in 4ae42f6

self.ann_id = 0

But for current official coco evaluation toolkit (https://github.com/cocodataset/cocoapi), it requires that the annotation id in ground truth file should start with 1, otherwise, it would cause wrong result. Check this: cocodataset/cocoapi#507 (comment)

Maybe we should change this to be compatible with coco evaluation toolkit.