GT-PCQA: Geometry-Texture Decoupled Point Cloud Quality Assessment with MLLM

Fuente: arXiv
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Main Authors: Zhang, Guohua, Jin, Jian, Liu, Meiqin, Yao, Chao, Lin, Weisi, Zhao, Yao
Format: Preprint
Published: 2026
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author Zhang, Guohua
Jin, Jian
Liu, Meiqin
Yao, Chao
Lin, Weisi
Zhao, Yao
author_facet Zhang, Guohua
Jin, Jian
Liu, Meiqin
Yao, Chao
Lin, Weisi
Zhao, Yao
contents With the rapid advancement of Multi-modal Large Language Models (MLLMs), MLLM-based Image Quality Assessment (IQA) methods have shown promising generalization. However, directly extending these MLLM-based IQA methods to PCQA remains challenging. On the one hand, existing PCQA datasets are limited in scale, which hinders stable and effective instruction tuning of MLLMs. On the other hand, due to large-scale image-text pretraining, MLLMs tend to rely on texture-dominant reasoning and are insufficiently sensitive to geometric structural degradations that are critical for PCQA. To address these gaps, we propose a novel MLLM-based no-reference PCQA framework, termed GT-PCQA, which is built upon two key strategies. First, to enable stable and effective instruction tuning under scarce PCQA supervision, a 2D-3D joint training strategy is proposed. This strategy formulates PCQA as a relative quality comparison problem to unify large-scale IQA datasets with limited PCQA datasets. It incorporates a parameter-efficient Low-Rank Adaptation (LoRA) scheme to support instruction tuning. Second, a geometry-texture decoupling strategy is presented, which integrates a dual-prompt mechanism with an alternating optimization scheme to mitigate the inherent texture-dominant bias of pre-trained MLLMs, while enhancing sensitivity to geometric structural degradations. Extensive experiments demonstrate that GT-PCQA achieves competitive performance and exhibits strong generalization.
format Preprint
id arxiv_https___arxiv_org_abs_2603_14951
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle GT-PCQA: Geometry-Texture Decoupled Point Cloud Quality Assessment with MLLM
Zhang, Guohua
Jin, Jian
Liu, Meiqin
Yao, Chao
Lin, Weisi
Zhao, Yao
Computer Vision and Pattern Recognition
With the rapid advancement of Multi-modal Large Language Models (MLLMs), MLLM-based Image Quality Assessment (IQA) methods have shown promising generalization. However, directly extending these MLLM-based IQA methods to PCQA remains challenging. On the one hand, existing PCQA datasets are limited in scale, which hinders stable and effective instruction tuning of MLLMs. On the other hand, due to large-scale image-text pretraining, MLLMs tend to rely on texture-dominant reasoning and are insufficiently sensitive to geometric structural degradations that are critical for PCQA. To address these gaps, we propose a novel MLLM-based no-reference PCQA framework, termed GT-PCQA, which is built upon two key strategies. First, to enable stable and effective instruction tuning under scarce PCQA supervision, a 2D-3D joint training strategy is proposed. This strategy formulates PCQA as a relative quality comparison problem to unify large-scale IQA datasets with limited PCQA datasets. It incorporates a parameter-efficient Low-Rank Adaptation (LoRA) scheme to support instruction tuning. Second, a geometry-texture decoupling strategy is presented, which integrates a dual-prompt mechanism with an alternating optimization scheme to mitigate the inherent texture-dominant bias of pre-trained MLLMs, while enhancing sensitivity to geometric structural degradations. Extensive experiments demonstrate that GT-PCQA achieves competitive performance and exhibits strong generalization.
title GT-PCQA: Geometry-Texture Decoupled Point Cloud Quality Assessment with MLLM
topic Computer Vision and Pattern Recognition
url https://arxiv.org/abs/2603.14951