When Big Models Train Small Ones: Label-Free Model Parity Alignment for
  Efficient Visual Question Answering using Small VLMs
Authors: name: Abhirama Subramanyam Penamakuri; name: Navlika Singh; name: Piyush Arora; name: Anand Mishra
Published: 2025-09-20 11:12:23

Abstract: Large Vision-Language Models (L-VLMs) have demonstrated remarkable
performance in various vision and language tasks, including visual question
answering (VQA). However, their high computational cost makes them impractical
for resource-constrained settings and inference-heavy applications. In
contrast, Small Vision-Language Models (S-VLMs) offer efficiency but suffer
from a significant performance gap compared to their larger counterparts. In
this work, we introduce the Model Parity Aligner (MPA), a novel framework
designed to systematically improve S-VLMs by leveraging unlabeled images and
effective knowledge transfer from L-VLMs. Instead of traditional knowledge
distillation methods that rely on labeled training data, MPA employs a
strategic parity-based approach that precisely identifies the knowledge
disparities between S-VLMs and L-VLMs, and optimizes training by targeting only
these disparities. We conduct extensive experiments on four diverse VQA
benchmarks, namely TextVQA, ST-VQA, ChartQA, and OKVQA, each of which requires
specialized reasoning capabilities such as text recognition, chart
interpretation, and commonsense and factual understanding. Our results
demonstrate that MPA consistently enhances the performance of S-VLMs on all
benchmarks, reducing the performance gap while maintaining computational
efficiency. We make our code publicly available.