arXiv Computer Vision

Reassessing Global Gradient-Norm Imbalance in BLIP Fine-Tuning Across Physical Domains

arXiv Computation and Language
3d ago

GAVAGAI: Referential Alignment for Infant-Scale Vision-Language Models via Balanced Optimal Transport

The paper introduces GAVAGAI, a method that adds a referential alignment variable to vision‑language models by solving a small assignment problem via entropic optimal transport. By allowing words to be assigned to a special NOTHING column and enforcing a capacity constraint on regions, the approach improves word‑to‑picture accuracy and localization on the SAYCam infant video corpus. Experiments show that the alignment loss boosts performance over a standard next‑token captioning baseline, especially under high non‑reference rates.

By Rajdeep Pal, Jotiraditya Banerjee, Saptarshi Pani
arXiv Computer Vision
Oct 16

Cross-Prompt Inference Mitigates Rare-Class Suppression in Imbalanced VLM Finetuning

The paper investigates how finetuning vision‑language models (VLMs) on class‑imbalanced data can severely hurt recall for rare classes, sometimes below zero‑shot performance. It discovers that using a different descriptive prompt at inference—termed cross‑prompt inference—recovers rare‑class recall across diverse VLMs and datasets, though it may slightly affect frequent‑class recall. Analysis with Tuning Contribution shows that cross‑prompt inference reduces reliance on finetuning‑induced computation, shifting the model toward its pretrained knowledge, and that the benefit disappears when the finetuning contribution is minimized.

By Emanuel Ben Baruch, Sivan Biham, Alon Shoshan, Yochai Zvik, Avi Ben-Cohen
arXiv AI
Oct 9

Rethinking Contrastive Loss in CLIP Post-training: A Complementary Framework with Frozen Text Encoder

The paper revisits the use of contrastive loss for post‑training CLIP models, showing that the reported catastrophic forgetting is mainly due to an overly large temperature parameter in the InfoNCE objective. By setting a smaller temperature, contrastive post‑training can actually improve CLIP. The authors introduce ComCLIP, a lightweight single‑epoch recipe that freezes the text encoder, trains the vision encoder with a properly tempered contrastive loss, an MSE anchoring loss, and a relational distillation loss, achieving comparable zero‑shot classification to CLIP‑Refine while significantly enhancing visual feature transferability and maintaining downstream compatibility with LLaVA.

By Zidan Wang, Yaqian Li, Xiaokai Zhang, Kaiwen Long, Kun He, Hanpeng Liu