Papers › Contracting Skeletal Kinematics for Human-Related Video Anomaly Detection

Contracting Skeletal Kinematics for Human-Related Video Anomaly Detection

23 Jan 2023arXiv:2301.09489archive 2025-07-28

Alessandro Flaborea, Guido D'Amely, Stefano D'arrigo, Marco Aurelio Sterpa, Alessio Sampieri, Fabio Galasso

Detecting the anomaly of human behavior is paramount to timely recognizing endangering situations, such as street fights or elderly falls. However, anomaly detection is complex since anomalous events are rare and because it is an open set recognition task, i.e., what is anomalous at inference has not been observed at training. We propose COSKAD, a novel model that encodes skeletal human motion by a graph convolutional network and learns to COntract SKeletal kinematic embeddings onto a latent hypersphere of minimum volume for Video Anomaly Detection. We propose three latent spaces: the commonly-adopted Euclidean and the novel spherical and hyperbolic. All variants outperform the state-of-the-art on the most recent UBnormal dataset, for which we contribute a human-related version with annotated skeletons. COSKAD sets a new state-of-the-art on the human-related versions of ShanghaiTech Campus and CUHK Avenue, with performance comparable to video-based methods. Source code and dataset will be released upon acceptance.

PaperPDFCodeCode Syntology ran

In Syntology Open this paper in Syntology's Atlas, the map of the papers in Syntology's graph and their citations.

For agents, Syntology's MCP tool lists every function and class Syntology harvested from this paper and whether it ran (how to connect): get_harvested_code_for_paper(arxiv_id="2301.09489")

Code

Syntology Ran 2 of 4 code samples harvested from 1 repository linked to this paper; 2 have no recorded run. Of those that ran: 2 ran with no contract checked.

By repository: official repository: 4 samples from 1 repository, 2 ran. The run record, sample by sample. “Ran” means executed on a synthesized input, not that the code is correct or reproduces the paper.

aleflabo/COSKAD officialpytorchMIT report

Repository list and official/mentioned flags are the archive's, frozen 2025-07-28. Reachability, where shown, is from one Syntology probe window (2026-09-16 to 2026-09-18); repositories not probed show nothing. GitHub stars are not tracked.

Code Syntology ran Syntology

4 samples harvested; 2 ran; 0 honoured the contract we drafted; 2 have no recorded run. Read from Syntology's graph 2026-09-24; that is when this build read the record, not when the samples ran.

2ran
2unverified

Licence: 0 of the 4 samples are pointer only, meaning Syntology does not serve that copy's text. This page shows no code text for any sample; each one links to its file in the repository.

Harvested from aleflabo/COSKAD. “Ran” means the sample executed on a synthesized input. It does not mean the output is correct, and nothing here reproduces the paper's results. “Honoured” and “violated” refer to a contract Syntology drafted from the code itself; “our draft was wrong” and “fixture could not drive it” are failures of Syntology's instrument, not of the code.

Each sample ends with its code_sha256, Syntology's identity for that exact code. An agent fetches the stored sample with Syntology's MCP tool get_code(code_sha256="…") (how to connect); click an identity to copy that call.

Repository labels, per sample. official repository: The archive marks this repository official for the paper. named in the paper: The archive records that the paper mentions this repository; it is not marked official. community (archive-listed): In the archive's code links for this paper, not marked official and not recorded as mentioned in the paper. found in paper text by Syntology: Syntology found this repository in the paper's own text; whether it is the authors' implementation is not asserted. community: Not in the archive's code links for this paper; a community repository Syntology harvested. Samples from a repository marked official are listed first. Licence labels name the repository's licence as recorded at harvest. “Pointer only” means Syntology does not serve that copy's text, for one of four reasons: no licence file was found; the licence was not identified; the licence is recorded as permissive but that copy's record is not marked cleared; or the licence is outside the permissive list Syntology serves text under (MIT, Apache-2.0, BSD and similar). Some licences outside that list permit redistribution, such as WTFPL, and GPL-3.0 under its conditions; they are simply not on the list. Hover a licence label for the reason. File links open the file on GitHub at the default branch, which may have changed since the harvest.

adjust_lr aleflabo/COSKAD/utils/model_utils.py official repository ran MIT (permissive) · 935b328e2a4ca4dd · report
calc_reg_loss aleflabo/COSKAD/utils/model_utils.py official repository ran MIT (permissive) · e8961ce4b45db673 · report
batch_cov_mat_step aleflabo/COSKAD/models/euclidean_encoder_staticCenter.py official repository unverified MIT (permissive) · d6ebbd621fb2721c · report
get_optim_and_scheduler aleflabo/COSKAD/utils/model_utils.py official repository unverified MIT (permissive) · 7e0144cbf00fd665 · report

Tasks

Anomaly DetectionOpen Set LearningVideo Anomaly Detection

Datasets

Introduced by this paper, per the archive.

HR-UBnormal

Results from the paper archive 2025-07-28

TaskDatasetModelMetricValueRank at snapshotLeaderboardReport
Anomaly Detection UBnormal COSKAD-hyperbolic AUC 65% #7 of 14 Archive leaderboard report
Anomaly Detection UBnormal COSKAD-euclidean AUC 64.9% #8 of 14 Archive leaderboard report
Anomaly Detection UBnormal COSKAD-radial AUC 62.9% #9 of 14 Archive leaderboard report
Video Anomaly Detection HR-Avenue COSKAD-euclidean AUC 87.8 #4 of 11 Archive leaderboard report
Video Anomaly Detection HR-Avenue COSKAD-hyperbolic AUC 87.3 #5 of 11 Archive leaderboard report
Video Anomaly Detection HR-Avenue COSKAD-radial AUC 82.2 #10 of 11 Archive leaderboard report
Video Anomaly Detection HR-ShanghaiTech COSKAD-euclidean AUC 77.1 #6 of 14 Archive leaderboard report
Video Anomaly Detection HR-ShanghaiTech COSKAD-hyperbolic AUC 75.6 #8 of 14 Archive leaderboard report
Video Anomaly Detection HR-ShanghaiTech COSKAD-radial AUC 75.2 #10 of 14 Archive leaderboard report
Video Anomaly Detection HR-UBnormal COSKAD-hyperbolic AUC 65.5 #3 of 8 Archive leaderboard report
Video Anomaly Detection HR-UBnormal COSKAD-euclidean AUC 65.2 #4 of 8 Archive leaderboard report
Video Anomaly Detection HR-UBnormal COSKAD-radial AUC 63.4 #5 of 8 Archive leaderboard report

Ranks are positions in the archive's leaderboards as they stood at the 2025-07-28 snapshot. Results published since then are not among these rows, so a rank here is not a current standing.

Report a problem or propose a change · a person checks every report against the paper or source before anything changes; decisions are listed on /corrections