Feature-Label Modal Alignment for Robust Partial Multi-Label Learning
Authors: Yu Chen, Weijun Lv, Yue Huang, Xiaozhao Fang, Jie Wen, Yong Xu, Guanbin Li
Organizations: School of Automation, Guangdong University of Technology, Guangzhou 510006, China · Shenzhen Key Laboratory of Visual Object Detection and Recognition, Harbin Institute of Technology, Shenzhen 518055, China · School of Computer Science and Engineering, Sun Yat-Sen University, Guangzhou 510275, China
In partial multi-label learning (PML), each instance is associated with a set of candidate labels containing both ground-truth and noisy labels. The presence of noisy labels disrupts the correspondence between features and labels, degrading classification performance. To address this challenge, we propose a novel PML method based on feature-label modal alignment (PML-MA), which treats features and labels as two complementary modalities and restores their consistency through systematic alignment. Specifically, PML-MA first employs low-rank orthogonal decomposition to generate pseudo-labels that approximate the true label distribution by filtering noisy labels. It then aligns features and pseudo-labels through both global projection into a common subspace and local preservation of neighborhood structures. Finally, a multi-peak class prototype learning mechanism leverages the multi-label nature where instances simultaneously belong to multiple categories, using pseudo-labels as soft membership weights to enhance discriminability. By integrating modal alignment with prototype-guided refinement, PML-MA ensures pseudo-labels better reflect the true distribution while maintaining robustness against label noise. Extensive experiments on both real-world and synthetic datasets demonstrate that PML-MA significantly outperforms state-of-the-art methods, achieving superior classification accuracy and noise robustness.
Figures & tables
Fig. 1: An example of partial multi-label learning. The candidate label set contains both ground-truth labels (in black: ”lake,” ”cloud,” ”sun,” and ”tree”) and noisy labels (in red: ”mountain,” ”sea,” ”grass,” and ”bird”).
Symbol
Description
X∈Rn×d
Feature matrix of n instances with d dimensions
Y∈{0,1}n×c
Candidate label matrix with c label classes
R∈Rn×c
Pseudo-label matrix ( 0≤rij≤yij )
Q∈Rc×c
Orthogonal basis matrix ( Q⊤Q=Ic )
P1∈Rd×m
Feature projection matrix
P2∈Rc×m
Pseudo-label projection matrix ( P2⊤P2=Im )
TABLE I: Summary of key notations.
Fig. 2: Overview of the proposed PML-MA framework. The method comprises: (1) Label Low-Rank Orthogonal decomposition ( LLRO ) decomposes candidate labels Y into orthogonal basis Q and pseudo-labels R ; (2) Global Modal Alignment ( LGMA ) projects features X and pseudo-labels R into a common subspace via P1 and P2 ; (3) Local Modal Alignment ( LLMA ) preserves neighborhood structures using similarity relationships; (4) Multi-peak Class Prototype learning ( LMCP ) models the multi-peak distribution where instance xi with pseudo-labels ri=[0.7,0.8,0.4,0] (yielding dii=1.9 ) is guided by multiple class prototypes. The final classifier P2P1⊤ is derived from the aligned projection matrices.
Data Set
avg.#CLs
PML-MA
PML-PLR
FBD-PML
PML-ND
P-LENFN
PAMB
PML-NI
PARTICLE
PML-fp
Mirflickr
3.35
.169±.004
.171±.003
.170±.003
.185±.004
.173±.004
.171±.032
.224±.006
.174±.037
.216±.002
Music-emotion
5.29
.208±.004
.210±.001
.212±.004
.211±.005
.213±.004
.210±.003
.254±.009
.221±.004
.238±.017
Music-style
6.04
.114±.006
.115±.003
.117±.006
.116±.005
.116±.005
.115±.004
.159±.012
.125±.004
.166±.023
YeastBP
18.84
.033±.002
.034±.002
.035±.002
.076±.003
.041±.002
.034±.007
.037±.002
.026±.012
.040±.002
emotions
3
.202±.021
.204±.019
.218±.022
.210±.020
.226±.023
.205±.020
.312±.056
.235±.022
.377±.004
4
.209±.015
.215±.018
.235±.019
.228±.020
.247±.022
.221±.022
.500±.047
.253±.022
.705±.013
TABLE II: Comparison of PML-MA with other state-of-the-art PML algorithms on HAMMING LOSS (mean ± std), where the best experimental performance (the smaller the better) is shown in boldface and the suboptimal is shown with an underscore.
Data Set
avg.#CLs
PML-MA
PML-PLR
FBD-PML
PML-ND
P-LENFN
PAMB
PML-NI
PARTICLE
PML-fp
Mirflickr
3.35
.108±.008
.109±.006
.116±.007
.113±.005
.118±.005
.112±.038
.126±.007
.127±.103
.124±.003
Music-emotion
5.29
.235±.007
.236±.008
.238±.008
.242±.006
.246±.009
.234±.007
.246±.008
.362±.014
.458±.114
Music-style
6.04
.137±.012
.136±.009
.138±.010
.137±.008
.138±.010
.135±.005
.137±.010
.221±.010
.445±.231
YeastBP
18.84
.195±.011
.208±.010
.225±.011
.215±.009
.256±.011
.230±.011
.220±.011
.404±.033
.269±.012
emotions
3
.156±.038
.158±.030
.172±.032
.165±.028
.180±.031
.160±.021
.188±.029
.250±.035
.293±.015
4
.165±.029
.172±.025
.185±.026
.178±.027
.192±.027
.177±.032
.211±.027
.263±.029
.407±.014
TABLE III: Comparison of PML-MA with other state-of-the-art PML algorithms on RANKING LOSS (mean ± std), where the best experimental performance (the smaller the better) is shown in boldface and the suboptimal is shown with an underscore.
Data Set
avg.#CLs
PML-MA
PML-PLR
FBD-PML
PML-ND
P-LENFN
PAMB
PML-NI
PARTICLE
PML-fp
Mirflickr
3.35
.176±.018
.183±.014
.196±.016
.189±.015
.282±.011
.275±.093
.296±.024
.198±.012
.292±.011
Music-emotion
5.29
.420±.012
.424±.013
.444±.017
.432±.015
.476±.019
.428±.032
.478±.019
.585±.036
.690±.140
Music-style
6.04
.331±.022
.338±.018
.349±.019
.342±.016
.356±.019
.343±.011
.345±.018
.405±.017
.620±.254
YeastBP
18.84
.544±.033
.548±.028
.560±.032
.552±.030
.597±.015
.564±.023
.553±.029
.999±.000
.685±.018
emotions
3
.235±.070
.241±.028
.255±.030
.246±.027
.298±.059
.244±.026
.299±.050
.307±.069
.458±.000
4
.283±.050
.297±.032
.318±.033
.309±.034
.329±.035
.333±.060
.355±.064
.324±.050
.542±.000
TABLE IV: Comparison of PML-MA with other state-of-the-art PML algorithms on ONE-ERROR (mean ± std), where the best experimental performance (the smaller the better) is shown in boldface and the suboptimal is shown with an underscore.
Data Set
avg.#CLs
PML-MA
PML-PLR
FBD-PML
PML-ND
P-LENFN
PAMB
PML-NI
PARTICLE
PML-fp
Mirflickr
3.35
.225±.004
.225±.005
.229±.078
.231±.004
.226±.006
.228±.007
.227±.005
.239±.054
.226±.012
Music-emotion
5.29
.402±.007
.404±.008
.408±.011
.406±.009
.407±.010
.410±.010
.409±.009
.510±.012
.589±.097
Music-style
6.04
.204±.014
.198±.010
.201±.012
.200±.011
.196±.009
.195±.008
.196±.013
.284±.013
.491±.206
YeastBP
18.84
.263±.009
.270±.010
.285±.012
.280±.011
.357±.016
.299±.049
.289±.009
.423±.162
.368±.015
emotions
3
.297±.030
.298±.028
.301±.032
.299±.030
.316±.029
.300±.036
.325±.026
.357±.045
.371±.029
4
.297±.035
.305±.030
.310±.031
.308±.029
.324±.032
.312±.028
.339±.031
.356±.031
.469±.009
TABLE V: Comparison of PML-MA with other state-of-the-art PML algorithms on COVERAGE (mean ± std), where the best experimental performance (the smaller the better) is shown in boldface and the suboptimal is shown with an underscore.
Data Set
avg.#CLs
PML-MA
PML-PLR
FBD-PML
PML-ND
P-LENFN
PAMB
PML-NI
PARTICLE
PML-fp
Mirflickr
3.35
.833±.011
.825±.010
.815±.015
.820±.012
.798±.007
.791±.019
.786±.009
.813±.136
.792±.005
Music-emotion
5.29
.633±.010
.630±.010
.615±.013
.628±.011
.610±.012
.626±.011
.608±.012
.506±.016
.435±.093
Music-style
6.04
.743±.017
.742±.010
.735±.014
.740±.012
.731±.016
.741±.007
.739±.015
.657±.012
.472±.200
YeastBP
5.93
.418±.020
.410±.020
.380±.023
.406±.021
.339±.015
.356±.022
.404±.022
.108±.016
.286±.009
emotions
3
.814±.043
.812±.020
.800±.030
.808±.025
.781±.033
.810±.017
.777±.028
.747±.035
.675±.005
4
.800±.026
.790±.030
.775±.035
.785±.032
.768±.028
.783±.036
.749±.034
.739±.033
.581±.003
TABLE VI: Comparison of PML-MA with other state-of-the-art PML and MLL algorithms on AVERAGE PRECISION , where the best experimental performance (the larger the better) is shown in boldface and the suboptimal is shown with an underscore.
Fig. 3: Results of PML-MA against other approaches with the Nemenyi test(CD = 2.1934 at 0.05 significance level).
Evaluation metric
FF
Critical value
Hamming Loss
23.1348
Ranking Loss
71.4812
One Error
54.1232
1.9785
Coverage
51.7904
Average precision
128.4977
TABLE VII: Summary of FRIEDMAN STATISTICS FF FOR EACH EVALUATION METRIC AT 0.05 SIGNIFICANCE LEVEL (# APPROACHES k = 9, DATA SETS N = 30).
Fig. 4: Results of PML-MA with varying values of trade-off parameters on birds dataset.
Fig. 5: The convergence curves of PML-MA on the synthetic datasets.
Component
Configuration and accordingly performance
LLRO
✓
✗
✓
✓
LGLMA
✓
✓
✗
✓
LMCP
✓
✓
✓
✗
emotions (avg.#CLs=4)
.800 ± .026
.793 ± .020
.785 ± .013
.796 ± .023
birds (avg.#CLs=4)
.597 ± .060
.590 ± .040
.584 ± .048
.595 ± .051
scene (avg.#CLs=5)
.813 ± .024
.811 ± .020
.807 ± .012
.810 ± .028
TABLE VIII: Ablation study results. Comparison of performance with and without each module, in metric Average precision . The best experimental performance is shown in boldface.
Fig. 6: Comparative experiment of low rank orthogonal decomposition and low rank sparse decomposition on yeast and reference datasets.
Appendix figures & tables2 assets
Supplementary material from the paper’s appendix.
Appendix
Datasets
#Instance
#Dim
#Class
avg.#CLs
avg.#GLs
Mirflickr
10433
100
7
3.35
1.77
Music _ emotion
6833
98
11
5.29
2.42
Music _ style
6839
98
10
6.04
1.44
YeastBP
6139
6139
127
5.93
5.54
emotions
593
72
6
3, 4, 5
1.86
birds
645
260
19
3, 4, 5
1.01
Appendix
TABLE IX: General Information of The nine Multi-label datasets and four partial multi-label learning datasets.
Method
Hl
Rl
Oe
Cov
Ap
avg
PML-MA
2.0833
1.2500
1.2500
1.6000
1.1000
1.4567
PML-PLR
2.9167
2.2000
2.3333
2.1833
2.2333
2.3733
FBD-PML
5.2333
4.9167
4.5333
4.5000
4.5333
4.7433
PML-ND
3.4167
3.5333
3.4167
3.4667
2.9333
3.3533
P-LENFN
6.7167
6.2167
6.1500
6.2333
5.7167
6.2067
PAMB
5.8500
4.9333
6.3000
5.6667
5.7167
5.6933
Appendix
TABLE X: The Average Rankings of Each Method Across All Five Metrics (Transposed)
Institute of Big Data Science and Industry, the School of Artificial Intelligence, and the Key Laboratory of Evolutionary Science Intelligence of Shanxi Province, Shanxi University, Taiyuan 030006, Shanxi, China