平衡coco格式json文件中的空目标图像和包含目标图像比例为1：1

import json
import random


def balance_empty_targets(coco_json_file, output_file):
    with open(coco_json_file, 'r') as file:
        data = json.load(file)

    image_ids_with_annotations = set(anno['image_id'] for anno in data['annotations'])

    images_with_targets = [image for image in data['images'] if image['id'] in image_ids_with_annotations]
    images_without_targets = [image for image in data['images'] if image['id'] not in image_ids_with_annotations]

    num_to_remove = len(images_without_targets) - len(images_with_targets)
    if num_to_remove > 0:
        images_to_remove = random.sample(images_without_targets, num_to_remove)
        images_without_targets = [image for image in images_without_targets if image not in images_to_remove]

    balanced_images = images_with_targets + images_without_targets

    # Update 'images' key with the new list of balanced images
    data['images'] = balanced_images

    with open(output_file, 'w') as file:
        json.dump(data, file)


if __name__ == '__main__':
    coco_json_file = './train.json'
    output_file = './balanced_coco.json'
    balance_empty_targets(coco_json_file, output_file)