normalize_labels.py

from __future__ import division
from PIL import Image
import os


img_dir = 'images'
lab_dir = 'labels'
out_dir = 'normalized-labels'


def normalize_label(label, width, height):
    cl, cx, cy, wx, wy = label
    return int(cl), cx/width, cy/height, wx/width, wy/height


if not os.path.exists(out_dir):
    os.makedirs(out_dir)

for filename in os.listdir(img_dir):
    if filename.endswith(".jpg"):
        im_path = os.path.join(img_dir, filename)
        filename_txt = filename.split('.')[0] + '.txt'
        lab_path = os.path.join(lab_dir, filename_txt)
        norm_lab_path = os.path.join(out_dir, filename_txt)

        # Open image
        im = Image.open(im_path)
        width, height = im.size

        # Open label
        with open(lab_path, "r") as f:
            label = map(float, f.readline().rstrip('\n').split(' '))

        # Create normalized label
        norm_label = normalize_label(label, width, height)

        # Save new label
        with open(norm_lab_path, "w") as f:
            str_norm_label = ' '.join(map(str, [norm_label[0]]) + ['{:.6f}'.format(x) for x in norm_label[1:]])
            f.write(str_norm_label)
            # print(str_norm_label)

        # print(im_path, width, height, label, norm_label)