使用语义分割时，我们使用labelme制作标签，但是生成的是json格式，往往需要转成Png格式。

因此，下面我写了一个批量转png代码。

import argparse
import base64
import json
import os
import os.path as osp
import imgviz
import PIL.Image
import yaml
from labelme.logger import logger
from labelme import utils

'''single json file'''
def main():
    logger.warning(
        "This script is aimed to demonstrate how to convert the "
        "JSON file to a single image dataset."
    )
    logger.warning(
        "It won't handle multiple JSON files to generate a "
        "real-use dataset."
    )

    parser = argparse.ArgumentParser()
    #parser.add_argument("json_file")
    parser.add_argument('--jsonfiles', nargs='?', const=True, default="datasets//before", help='resume most recent training') #设置输入路径
    parser.add_argument("-o", "--out", default="datasets//png")  #设置输出路径
    args = parser.parse_args()
    import glob
    jsonfiles = glob.glob(args.jsonfiles+"/*.json")
    print(jsonfiles)
    for json_file in jsonfiles:
        if args.out is None:
            out_dir = osp.basename(json_file).replace(".", "_")
            out_dir = osp.join(osp.dirname(json_file), out_dir)
        else:
            out_dir = args.out
        if not osp.exists(out_dir):
            os.mkdir(out_dir)

        data = json.load(open(json_file))
        imageData = data.get("imageData")

        if not imageData:
            imagePath = os.path.join(os.path.dirname(json_file), data["imagePath"])
            with open(imagePath, "rb") as f:
                imageData = f.read()
                imageData = base64.b64encode(imageData).decode("utf-8")
        img = utils.img_b64_to_arr(imageData)

        label_name_to_value = {"_background_": 0}
        for shape in sorted(data["shapes"], key=lambda x: x["label"]):
            label_name = shape["label"]
            if label_name in label_name_to_value:
                label_value = label_name_to_value[label_name]
            else:
                label_value = len(label_name_to_value)
                label_name_to_value[label_name] = label_value
        lbl, _ = utils.shapes_to_label(
            img.shape, data["shapes"], label_name_to_value
        )

        label_names = [None] * (max(label_name_to_value.values()) + 1)
        for name, value in label_name_to_value.items():
            label_names[value] = name

        lbl_viz = imgviz.label2rgb(
            label=lbl, image=imgviz.asgray(img), label_names=label_names, loc="rb"
        )

        label_name  = json_file.split('\\')[-1].replace('.json','.png')
        image_name  = json_file.split('\\')[-1].replace('.json','.jpg')
        PIL.Image.fromarray(img).save(osp.join(out_dir, image_name))
        utils.lblsave(osp.join(out_dir, label_name), lbl)
        PIL.Image.fromarray(lbl_viz).save(osp.join(out_dir, "label_viz.png"))

        with open(osp.join(out_dir, "label_names.txt"), "w") as f:
            for lbl_name in label_names:
                f.write(lbl_name + "\n")

        # 生成info.yaml文件
        # logger.warning('info.yaml is being replaced by label_names.txt')
        # info = dict(label_names=label_names)
        # with open(osp.join(out_dir, 'info.yaml'), 'w') as f:
        #     yaml.safe_dump(info, f, default_flow_style=False)

        logger.info("Saved to: {}".format(out_dir))

if __name__ == "__main__":
    main()
 

效果展示: