def create_annotations(directory, img_dir):
    annotations = {}
    for dir_name in os.listdir(directory):
        if not (dir_name == "images"):
            for _, _, files in os.walk(os.path.join(directory, dir_name)):
                mat = scipy.io.loadmat(os.path.join(directory, dir_name, ANNOTATION_FILE))

                for i, img_file in enumerate(sorted(files)):
                    if not (img_file.endswith(".mat")):
                        new_img_file = dir_name + "_" + img_file

                        image = {
                            "name":     new_img_file,
                            "objects":  []
                        }

                        for segmentation in mat["polygons"][0][i]:
                            if segmentation.any():
                                image["objects"].append(segmentation.tolist())
                        
                        annotations[new_img_file] = image

                        shutil.move(os.path.join(directory, dir_name, img_file), os.path.join(img_dir, new_img_file))

    with open(os.path.join(directory, SAVE_FILE), 'w') as output_json_file:
        json.dump(annotations, output_json_file)

    for dir_name in os.listdir(directory):
        if not (dir_name == "images" or dir_name == "annotations.json"):
            shutil.rmtree(os.path.join(directory, dir_name))