arXiv Computer Vision

An Error Budget for Shuffled Multimodal Windows in the 3rd WEAR Challenge: Stacking, Count Constraints and Seam Matching

arXiv Machine Learning
Sep 24

When Adaptation Hurts: Split Sensitivity and Person-Level Negative Transfer in Federated Wearable Onboarding

The paper evaluates six onboarding strategies for federated wearable models on five datasets using a leakage‑controlled protocol that fixes source checkpoints and separates calibration from evaluation. Results show that while average accuracy is high, person‑level performance can drop significantly, with some methods causing negative transfer for certain users. The study highlights that mean accuracy alone is insufficient and provides an auditable benchmark and failure map for future development.

By Rahil Aftab, Vineet Kumar Rakesh, Soumya Mazumdar, Tapas Samanta
arXiv AI
Aug 24

Aggregate, Don't Adapt: Subject-Level Posterior Aggregation and Transductive Calibration for Cross-Site Parkinsonian Gait Severity

The paper reports the winning solution to the MoCha 2026 Parkinsonian Gait Benchmark, achieving a macro‑F1 score of 0.6945 on unseen clinical sites. The approach relies on a frozen public motion encoder followed by a single 4×512 linear layer, and gains are largely attributed to three key steps: exact replication of the benchmark’s head recipe, averaging per‑walk posteriors at the subject level, and a label‑free transductive calibration of feature means and decision thresholds. Extensive ablation studies show that fine‑tuning the encoder or using alternative encoders does not improve performance, and the subject‑level aggregation is identified as the primary contributor to the top score.

By Junlong Shen
arXiv Computer Vision
Aug 27

HEDGE: A Calibrated Ensemble for A/H Recognition

arXiv:2607.12176v2 Announce Type: replace Abstract: Ambivalence and hesitancy (A/H) undermine digital behaviour-change interventions, and recognizing them automatically from video is the goal of the...

By Josep Cabacas-Maso, Ismael Benito-Altamirano, Carles Ventura
arXiv Computer Vision
1d ago

Where Do Reported Long-Video QA Gains Come From? A Controlled Audit of Frame Selection, Evidence Injection, and Expert Routing

The paper introduces VideoRouteAudit, a controlled experiment that isolates the effects of frame selection, evidence injection, and expert routing in long‑video question answering. On a large Video‑MME benchmark, no frame selector outperforms uniform sampling, and the gains from evidence injection or model swapping are largely attributable to the specific model or data ordering rather than the selection strategy itself. The study also corrects earlier results, showing that ASR transcripts can either help or hurt performance depending on placement, and that swapping the answering model yields the largest performance contrast.

By Shih-Yao Lin
arXiv Computer Vision
Sep 25

Training-Free Hold-Usage Detection in Sport Climbing with Foundation Pose Models

The paper presents a training‑free method for detecting which holds a climber uses in sport climbing videos by leveraging a frozen foundation pose model (Sapiens) that provides fingertip and toe keypoints. Using a simple proximity test, mutual exclusion, and a temporal‑persistence rule, the approach achieves high F_1 scores (up to 90.2%) on the Way Up dataset without any climbing‑specific training, outperforming repurposed pose pipelines. The resulting automatic predictions enable accurate coaching statistics, such as climb time and pace, with Pearson correlations of 1.00 and 0.94 respectively.

By Abu Bakar, Abdullah Aftab, Amir Hamza
arXiv AI
Sep 24

Ask Which, Not How Good: Sizing Benchmarks Scored by an LLM

The study analyzes 373,019 judgments from LLM‑scored benchmarks, decomposing variance into system, item, judge, and interaction components via generalizability theory. It finds that with a single judge, generalizability converges to a ceiling determined by the system‑by‑judge variance, which is substantially lower in pairwise preference settings, allowing one judge to suffice. The research also reveals significant biases in presentation order and highlights that many published win‑rate claims fall below the measured floor of the benchmarks.

By Atul Anand