From Head to Tail: Towards Balanced Representation in Large
  Vision-Language Models through Adaptive Data Calibration
Authors: name: Mingyang Song, name: Xiaoye Qu, name: Jiawei Zhou, name: Yu Cheng

Large Vision-Language Models (LVLMs) have achieved significant progress in
combining visual comprehension with language generation. Despite this success,
the training data of LVLMs still suffers from Long-Tail (LT) problems, where
the data distribution is highly imbalanced. Previous works have mainly focused
on traditional VLM architectures, i.e., CLIP or ViT, and specific tasks such as
recognition and classification. Nevertheless, the exploration of LVLM (e.g.
LLaVA) and more general tasks (e.g. Visual Question Answering and Visual
Reasoning) remains under-explored. In this paper, we first conduct an in-depth
analysis of the LT issues in LVLMs and identify two core causes: the
overrepresentation of head concepts and the underrepresentation of tail
concepts. Based on the above observation, we propose an Adaptive
Data Refinement Framework (ADR), which
consists of two stages: Data Rebalancing (DR)
and Data Synthesis (DS). In the DR stage, we
adaptively rebalance the redundant data based on entity distributions, while in
the DS stage, we leverage Denoising Diffusion Probabilistic Models (DDPMs) and
scarce images to supplement underrepresented portions. Through comprehensive
evaluations across eleven benchmarks, our proposed ADR effectively mitigates
the long-tail problem in the training data, improving the average performance
of LLaVA 1.5 relatively by 4.36%, without increasing the training data volume.