python convert.py PATH_TO_ANNOTATION

# convert.py 
import xml.etree.ElementTree as ET
import pickle
import os,sys
from os import listdir, getcwd
from os.path import join

classes=["08901725101053","08901030664205","08901030662010","04902430772877","08901030612381","08901512540102"]


def convert(size,box):
    # Conversion from VOC to YOLO format
    dw = 1./(size[0])
    dh = 1./(size[1])
    x = (box[0] + box[1])/2.0 - 1
    y = (box[2] + box[3])/2.0 - 1
    w = box[1] - box[0]
    h = box[3] - box[2]
    x = x*dw
    w = w*dw
    y = y*dh
    h = h*dh
    return (x,y,w,h)

#print ann_file
def converting_annotation(ann_file):
    for ann in ann_file:
        txt_file= ann.split('.')[0]+'.txt'
        in_file=open(ann_dir+ann)
        out_file =open(ann_dir+txt_file, 'w')
        tree=ET.parse(in_file)
        root = tree.getroot()
        size = root.find('size')
        w = int(size.find('width').text)
        h = int(size.find('height').text)

        print w,h
        for obj in root.iter('object'):
            cls=obj.find('name').text
            if cls not in classes:
                continue
            cls_id=classes.index(cls)
            xmlbox = obj.find('bndbox')
            b = (float(xmlbox.find('xmin').text), float(xmlbox.find('xmax').text), float(xmlbox.find('ymin').text), float(xmlbox.find('ymax').text))
            data = convert((w,h), b)
            out_file.write(str(cls_id) + " " + " ".join([str(a) for a in data]) + '\n')


if __name__ == '__main__': 
    ann_dir=sys.argv[1]
    ann_file=os.listdir(ann_dir)
    ann_file.sort()
    print(ann_file)
    converting_annotation(ann_file)