ABCnet constructs gt data for algorithm verification

1. The points in gt are the original labeled points, not the points after Bessel fitting.

2. The points in gt are in the opposite order of the training data, gt is counterclockwise, and train is clockwise

So, the detection result [[10,20], [20, 20], [20, 40], [10,40]] is clockwise, the GT result 10,40,20,40,20,20,10,20 is anticlockwise.