Multimodal Structure Learning: Disentangling Shared and Specific Topology via Cross-Modal Graphical Lasso
Authors: Fei Wang, Yutong Zhang, Xiong Wang
Organizations: Department of Applied Mathematics and Statistics, Stony Brook University · School of Mathematics, Sichuan University · School of Computer Science and Technology, USTC
Learning interpretable multimodal representations inherently relies on uncovering the conditional dependencies between heterogeneous features. However, sparse graph estimation techniques, such as Graphical Lasso (GLasso), to visual-linguistic domains is severely bottlenecked by high-dimensional noise, modality misalignment, and the confounding of shared versus category-specific topologies. In this paper, we propose Cross-Modal Graphical Lasso (CM-GLasso) that overcomes these fundamental limitations. By coupling a novel text-visualization strategy with a unified vision-language encoder, we strictly align multimodal features into a shared latent space. We introduce a cross-attention distillation mechanism that condenses high-dimensional patches into explicit semantic nodes, naturally extracting spatial-aware cross-modal priors. Furthermore, we unify tailored GLasso estimation and Common-Specific Structure Learning (CSSL) into a joint objective optimized via the Alternating Direction Method of Multiplier (ADMM). This formulation guarantees the simultaneous disentanglement of invariant and class-specific precision matrices without multi-step error accumulation. Extensive experiments across eight benchmarks covering both natural and medical domains demonstrate that CM-GLasso establishes a new state-of-the-art in generative classification and dense semantic segmentation tasks.
Figures & tables
Figure 1: The Pipeline of CM-GLasso. (a) Text visualization and unified SigLIP 2 feature extraction. (b) Cross-attention distillation condenses patches into semantic nodes. (c) Attention footprints derive spatial-aware cross-modal priors. (d-e) Nonparanormal transformation strictly ensures Gaussianity for the subsequent joint ADMM optimization, simultaneously disentangling shared ( Θcom ) and specific ( S(c) ) topologies. (f) Learned structures govern generative classification and topology-aware segmentation.
Dataset
Method
F1
ACC
CUB-200-2011
ShuffleNetV2 [ 29 ]
0.8774
0.8763
DA-VPT [ 31 ]
—
0.9130
PRO-VPT [ 33 ]
—
0.9170
VFPT [ 46 ]
—
0.9050
MT-ASM [ 25 ]
—
0.8800
CM-GLasso (Ours)
0.8836
0.9283
Table 1: Comparative results on classification tasks.
Dataset
Method
mIoU
ADE20K
OneFormer [ 17 ]
0.5700
InternImage-H [ 41 ]
0.6290
OmniVec2 [ 36 ]
0.5850
CM-GLasso (Ours)
0.6401
Kvasir-SEG
Polyp-PVT [ 6 ]
0.8640
PolypMixNet [ 19 ]
0.8885
Table 2: Comparative results on semantic segmentation (mIoU).
Encoder
ACC
mIoU
BERT+ViT (Het.)
84.23
53.27
CLIP text+ViT [ 30 ]
88.02
59.89
Render+SigLIP 2
91.97
68.65
Table 3: Ablation: Text Encoding Strategy.
Strategy
ACC
mIoU
PCA ( 768→p )
70.86
44.18
Linear FC
87.37
62.93
Cross-Attn (Ours)
91.97
68.65
Table 4: Ablation: Patch-to-Node Mapping.
Status
SW Pass
ACC
mIoU
w/o Trans.
∼ 23%
83.58
59.02
w/ Trans.
∼ 88%
91.97
68.65
Table 5: Ablation: Nonparanormal Transform.
Method
CSR
Gen. Gap
Indep. GLasso [ 11 ]
—
8.29%
Two-stage [ 5 ]
0.37
3.04%
Joint ADMM
0.42
1.93%
Table 6: Ablation: Optimization (CSR: Common Ratio).
Matrix Used
ACC
mIoU
Only Θcom
84.82
63.17
Only S(c)
88.43
65.58
Θcom+S(c)
91.97
68.65
Table 7: Ablation: Task Head Precision Matrix.
Direction
kˉ∗
k∗=0 Ratio
Text → Image
15.6
13.8%
Image → Text
6.7
33.1%
Self-Priors
≈ 0.1
¿84.0%
Table 8: Ablation: Prior Selection via eBIC.
Metric
PCA
FC
Ours
Graph Structure Quality
Avg. Edges ∣E∣ in Θ(c)
987
491
238
Spurious Edge Ratio (%) ↓
68.7
31.2
11.4
kˉ∗ (Prior Utilization)
1.2
5.8
15.6
Interpretability & Architecture
Native p×p Prior
×
×
✓
Table 9: Detailed metrics for Patch-to-Node mapping strategies. ∣E∣ denotes the average number of edges.
ρ↓ \ γs→
0.01
0.05
0.10
0.20
0.01
90.53/66.94
91.02/67.53
91.18/67.72
90.61/67.03
0.05
91.27/67.68
91.64/68.27
91.97/68.65
91.41/67.91
0.10
91.12/67.56
91.53/68.14
91.82/68.47
91.23/67.63
0.20
90.46/66.81
90.83/67.24
91.04/67.40
90.21/66.59
Table 10: Sensitivity analysis of ρ and γs . Values are presented as ACC(%) / mIoU(%).
Input Images
GAM Visualizations
CUB-200
CIFAR-10
CIFAR-100
Caltech-256
Figure 2: GAM visualization of the classification head HC . For each dataset (CUB-200-2011, CIFAR-10, CIFAR-100, Caltech-256), four input images (left block) are paired with their GAM heatmaps (right block). Warm regions (red/yellow) indicate spatially discriminative areas; cool regions (blue) indicate low contribution. CM-GLasso consistently focuses on class-discriminative semantics ( e.g. , bird head/wings, vehicle contours) rather than background noise, validating that cross-modal prior guidance improves classification interpretability.
Sample 1
Sample 2
Sample 3
Image
GT
Ours
Image
GT
Ours
Image
GT
Ours
ADE20K
Kvasir
VOC-2012
COCO
Figure 3: Qualitative segmentation results of HS . For each dataset (ADE20K, Kvasir-SEG, PASCAL VOC-2012, MS COCO-2014), three sample triplets are shown: input image, Ground Truth (GT), and CM-GLasso prediction (Ours). Our method produces precise boundaries and correctly captures long-range semantic dependencies ( e.g. , polyp edges, sky–water reflections, building–ground transitions), validating the benefit of joint ADMM optimization with cross-modal prior guidance.