Convert Labelme json to YOLO format

labelme2yolo.py

# -*- coding: utf-8 -*-

'''
LabelMe JSON format -> YOLO txt format
save dataset in dataset/
output will be saved in result/
'''

import json
import os


def convert(size, box):
    """Each row of yolo format is class x_center y_center width height format"""
    dw = 1. / size[0]
    dh = 1. / size[1]
    x = (box[0] + box[1]) / 2.0
    y = (box[2] + box[3]) / 2.0
    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)


def read_classes(classes_file_path):
    with open(classes_file_path) as f:
        classes = f.read().split()
    return {cls: i for i, cls in enumerate(classes)}


if __name__ == '__main__':
    """-------------------------------------------------------------------"""

    """ Configure Paths"""
    mypath = "./dataset/"
    outpath = "./result/"
    classes_file_path = "./classes.names"

    classes = read_classes(classes_file_path)
    # list_file = open('%s_list.txt'%(wd), 'w')

    """ Get input json file list """
    json_name_list = []
    for file in os.listdir(mypath):
        if file.endswith(".json"):
            json_name_list.append(file)

    """ Process """
    for json_name in json_name_list:
        txt_name = json_name.rstrip(".json") + ".txt"
        """ Open input text files """
        txt_path = mypath + json_name
        print("Input:" + txt_path)
        txt_file = open(txt_path, "r")

        """ Open output text files """
        txt_outpath = outpath + txt_name
        print("Output:" + txt_outpath)
        txt_outfile = open(txt_outpath, "w")

        """ Convert the data to YOLO format """
        json_file = json.load(txt_file)
        for shape in json_file["shapes"]:
            if "label" in shape:
                points = shape["points"]
                cls = shape["label"]
                cls_id = classes[cls]
                x_all = [p[0] for p in points]
                y_all = [p[1] for p in points]
                xmin = min(x_all)
                xmax = max(x_all)
                ymin = min(y_all)
                ymax = max(y_all)

                img_path = json_file["imagePath"]

                w = json_file["imageWidth"]
                h = json_file["imageHeight"]

                print(w, h)
                print(xmin, xmax, ymin, ymax)
                b = (xmin, xmax, ymin, ymax)
                bb = convert((w, h), b)
                print(bb)
                txt_outfile.write(str(cls_id) + " " + " ".join([str(a) for a in bb]) + '\n')
        txt_outfile.close()