A personal tool for transforming annotations among rolabelImg、COCO and DOTA and so on...

RLIS格式: 详细介绍见 https://zhuanlan.zhihu.com/p/275720038,https://github.com/msnh2012/CasiaLabeler, 标注工具软件名称为CasiaLabeler。 CasiaLabeler是一款非常轻量的标注软件，支持win10、ubuntu18和mac10.13+平台。主要适用于目标检测和实例分割等场景。可用于Faster RCNN, Mask RCNN, Yolo系列, SSD系列, Centernet系列等。

Classic style of rolabelImg: https://github.com/cgvict/roLabelImg

Where angle θ:[0,pi/2), which is the angle

and DOTA style: see https://captain-whu.github.io/DOTA/dataset.html

x1, y1, x2, y2, x3, y3, x4, y4, category, difficult

Note that the points are arranged in a clockwise order.

So my method is:

1)Calculate xmin,ymin,xmax,ymax, and you will find they correspond to 4 points of OBB like (x1,ymin) (xmax,y2) (x3,ymax) (x4,ymin) in a clockwise order(when θ<pi/2);

2)Choose a first-point as (x1,y1) and alculate 4 points;For me ,I choose top-left point(x1,ymin) when θ<pi/2 and (xmax,y1) when θ>=pi/2;

3)Store the xml to txt.

More about OBB: https://zhuanlan.zhihu.com/p/459018810

qucikdraw