The HARDness ESTimation package: A library for ranking images from a dataset by hardness with respect to a specific detector. Currently, we provide examples in the library for torchvision datasets and detectors, but other datasets and detectors can be used by converting the data to the torchvision format.

To install:

pip install hardest

Here we provide instructions for computing the hardness of an entire dataset. Firstly obtain a pytorch dataset:

from torchvision.datasets.coco import CocoDetection
import itertools
from os.path import join
import torchvision.transforms as T
from hardest.utils import coco_api_to_torchvision

coco_dir = "<path/to/coco>"

transform = T.Compose([
    T.PILToTensor(),
    T.ConvertImageDtype(torch.float),
])

val_dataset = CocoDetection(
    root = join(coco_dir, "val2017"),
    annFile = join(coco_dir, "annotations", "instances_val2017.json"),
    transform = transform,
    target_transform = coco_api_to_torchvision
)

# Run on a subset of the dataset
n_examples = 50
images, targets = zip(*itertools.islice(val_dataset, n_examples))

Obtain detections:

import torch, torchvision

model = torchvision.models.detection.retinanet_resnet50_fpn(pretrained=True)
model.eval()
with torch.no_grad():
    detections = [model([image])[0] for image in images]

Choose a definition of hardness:

from hardest.pycocotools import TotalFalse
hardness_definition = TotalFalse()

Estimate hardness using annotations:

from hardest.hardness_strategies import SupervisedHardnessCalculation
rank = SupervisedHardnessCalculation(hardness_definition).eval_dataset(
    detections,
    targets,
    images,
)

If annotations are not available, you can estimate hardness without annotations:

from hardest.hardness_strategies import ScoreSamplingHardnessCalculation
rank = ScoreSamplingHardnessCalculation(hardness_definition, n_samples=10).eval_dataset(detections, images)

To repeat the experiments from our paper (details here), first download the COCO Dataset (you only need 2017 Val images and 2017 Train/Val annotations) as well as the nuImages dataset and convert it to a COCO compatible format using these instructions. Then export the detections for your desired detector to torchvision json format.

Finally, run the script:

python scripts/paper_experiments.py --coco-root datasets/coco --nuimages-root datasets/nuimages-coco --save-dir ./results --detection-path-coco detections/coco --detection-path-nuimages detections/nuimages

This will require that you have stored detections in json files in the appropriate paths and downloaded the datasets to the specified paths.

To reproduce the nuimages results you will need to convert the nuimages dataset to the coco schema: https://github.com/open-mmlab/mmdetection3d/blob/master/configs/nuimages/README.md

If you use the package in your research please consider citing our paper:

Ayers, E., Sadeghi, J., Redford, J., Mueller, R., & Dokania, P. K. (2022). Query-based Hard-Image Retrieval for Object Detection at Test Time. Thirty-Seventh AAAI Conference on Artificial Intelligence. doi:10.48550/ARXIV.2209.11559

• Jonathan Sadeghi
• Edward Ayers

• Anuj Sharma
• Blaine Rogers
• Romain Mueller
• Zygmunt Lenyk