upscale_coco.py

import argparse
import json
import os
import time

import cv2
import numpy as np
from coco import COCO


def parse_args():
    parser = argparse.ArgumentParser(description="Upscale COCO dataset")
    parser.add_argument(
        "--inputs",
        "-i",
        type=str,
        default="/coco",
        help="input directory for coco dataset",
    )
    parser.add_argument(
        "--outputs",
        "-o",
        type=str,
        default="/cocoup",
        help="output directory for upscaled coco dataset",
    )
    parser.add_argument(
        "--images", "-im", type=str, default="val2017", help="image directory"
    )
    parser.add_argument(
        "--annotations",
        "-a",
        type=str,
        default="annotations/instances_val2017.json",
        help="annotations directory",
    )
    parser.add_argument(
        "--size",
        required=True,
        type=int,
        nargs="+",
        help="upscaled image sizes (e.g 300 300, 1200 1200",
    )
    parser.add_argument(
        "--format",
        "-f",
        type=str,
        default="jpg",
        help="image format")
    return parser.parse_args()


def upscale_coco(indir, outdir, image_dir, annotate_file, size, fmt):
    # Build directories.
    print("Building directories...")
    size = tuple(size)
    image_in_path = os.path.join(indir, image_dir)
    image_out_path = os.path.join(outdir, image_dir)
    path, fil = os.path.split(annotate_file)
    annotate_out_path = os.path.join(outdir, path)
    annotate_out_file = os.path.join(annotate_out_path, fil)
    annotate_in_file = os.path.join(indir, annotate_file)
    if not os.path.exists(image_out_path):
        os.makedirs(image_out_path)
    if not os.path.exists(annotate_out_path):
        os.makedirs(annotate_out_path)

    # Read annotations.
    print("Reading COCO dataset...")
    coco = COCO(annotate_in_file)
    print(len(coco.imgs), "images")
    print(len(coco.anns), "annotations")

    # Upscale annotations.
    print("Upscaling annotations...")
    annotations = []
    for idx in coco.anns:
        ann = coco.anns[idx]
        # Scaling factors
        img = coco.imgs[ann["image_id"]]
        sx = size[0] / img["width"]
        sy = size[1] / img["height"]
        # Bounding boxes
        bb = ann["bbox"]
        bb[0] = bb[0] * sx
        bb[1] = bb[1] * sy
        bb[2] = bb[2] * sx
        bb[3] = bb[3] * sy
        # Area
        ann["area"] = ann["area"] * sx * sy
        annotations.append(ann)

    # Upscale images.
    print("Upscaling images...")
    count = 0
    images = []
    for idx in coco.imgs:
        img = coco.imgs[idx]
        # Load, upscale, and save image.
        image = cv2.imread(os.path.join(image_in_path, img["file_name"]))
        if len(image.shape) < 3 or image.shape[2] != 3:
            # some images might be grayscale
            image = cv2.cvtColor(image, cv2.COLOR_GRAY2RGB)
        image = cv2.resize(image, size, interpolation=cv2.INTER_LINEAR)
        cv2.imwrite(os.path.join(image_out_path,
                    img["file_name"][0:-3] + fmt), image)
        # Update image file extension
        img["file_name"] = img["file_name"][0:-3] + fmt
        # Image dimensions
        img["width"] = size[0]
        img["height"] = size[1]
        count = count + 1
        # print(count, end=' ', flush=True)
        images.append(img)

    # Save annotations.
    print("Saving annotations...")
    with open(annotate_in_file) as f:
        dataset = json.load(f)
    dataset["images"] = images
    dataset["annotations"] = annotations
    with open(annotate_out_file, "w") as outfile:
        json.dump(dataset, outfile)
    print("Done.")


def main():
    # Get arguments.
    args = parse_args()
    # Upscale coco.
    upscale_coco(
        args.inputs, args.outputs, args.images, args.annotations, args.size, args.format
    )


main()