json类型文件转为yolo可识别的txt文件

# --把4点标注的json文件转化为（x_c,y_c,h,w,theta)的yolo txt 格式
import json
import os
import math
import random

my_class = ["bottle"]


def convert(image_id):

    in_file = 'annotations/%s.json' % image_id
    out_file = open('labels/%s.txt' % image_id, 'w')
    with open(in_file) as f_obj:
        label = json.load(f_obj)

    for bbox in label["shapes"]:
        vertices = bbox["points"]  # 顶点列表
        a, b, c, d = vertices

        x_c = (a[0]+b[0]+c[0]+d[0])/4
        y_c = (a[1] + b[1] + c[1] + d[1]) / 4