ML/CV engineer (new grad · Seoul · open to remote). I find and diagnose measurement problems in pose-estimation tooling.

• 20 merged PRs in open source, including Ultralytics and Roboflow supervision
• Wrote the first version of supervision's COCO keypoint mAP metric, shipped in 0.31.0
• Author of poseaudit and Epokio (both on PyPI)

📧 bkbkjang@gmail.com · 🎮 itch.io

Ultralytics (YOLO) · #26564, issue #26563

• Problem: convert_coco(use_keypoints=True) kept people with no labelled keypoints, so pose validation counted them as targets and under-reported pose mAP. The official COCO pose numbers were unaffected; it hit data converted with convert_coco and custom labels with fully occluded people.
• My part: found and reproduced it against pycocotools, and proposed a validator-side fix (yolo11n-pose on a 200-image COCO val2017 sample: pose mAP50-95 0.341 → 0.486).
• Result: the maintainers fixed it at the source with a one-line change in the converter instead. With their fix, they measured yolo26n-pose on my 200-image sample going from 0.347 to 0.576, matching pycocotools.

supervision (Roboflow) · #2687

• My part: wrote the initial sv.metrics.KeyPointMeanAveragePrecision (COCO keypoint mAP using OKS) and pycocotools parity tests; on 200 COCO val2017 images, AP, AP50, AP75, APm and APl matched pycocotools within 3e-9.
• Result: the maintainer substantially extended it before release. It shipped as one of the headline features of 0.31.0.
• Earlier: fixed from_yolo reading pose labels as polygons (#2655), later extended by the maintainer.

poseaudit · Python · PyPI
Checks how far angles and lengths computed from pose keypoints disagree with the labels, the way a measuring device is validated (bias, limits of agreement, ICC). On 322 left elbows from 200 COCO val2017 images, YOLO11n-pose disagrees with the labels by 15° or more on 58% of small arms (under 30 px) vs 26% of large ones (over 60 px). Much of that is label noise: the labels alone would put 30–44% of small arms and 17–31% of large ones off by 15° or more.

_{Photos: COCO val2017, CC BY 4.0}

Epokio · Python · PyPI
Sends a phone alert when an ML training run stalls, hits NaN or finishes, by reading the logs it already writes (Ultralytics, Hugging Face, Lightning, Keras, TensorBoard). No code changes, no account.

lidtilt · Python Reads the MacBook lid angle sensor to remove the lid's tilt from webcam head pitch.

Stella Ball · browser game A small browser game. Play on itch.io →

• ultralytics#26651: SAM prompts for a folder or video reached only the first image. I made them apply to the whole source. In review the maintainer caught that my version modified the caller's arrays in place; I fixed it, and they moved the forwarding to the streaming entry point.
• ultralytics#26635: every DataLoader worker drew the same Albumentations augmentations. I traced it and proposed reseeding per worker; the maintainer reworked the final commit.
• sktime#11233: re-enabled tests for two estimators that were skipped by mistake.

All merged pull requests →