CAIR IIT Mandi
Surface2Anatomy

Scientific Validation & Benchmarks

CT-ORG Cohort (N=215) • Phase 16

Quantitative evaluation across held-out clinical test splits, SOTA deep learning comparisons, physical surface occlusion studies, literature-matched subsets, and whole-body cranial error resolution.

Macro MRE23.22 mm-55.8% vs PNet++
SDR ≤ 20mm54.9%+75.0% vs DGCNN
FLARE22 MRE21.30 mmZero-Shot Transfer
Brain Error-78.1%Phase 16 Retrained

S2A-Net Outperforms Classical & Deep Learning Baselines Across All Metrics

Evaluating classical linear regression, statistical shape models (SSM/PCA), PointNet++, DGCNN, and our proposed Target-Query Point Transformer across all 104 anatomical organs under strictly identical canonical coordinate alignment and train/test splits (N=215).

-55.8% Error vs PointNet++
Proposed ArchitectureRank 1

S2A-Net (Ours)

Multi-scale surface tokens + 104 learned queries + cross-attention decoder.

Macro MRE23.22 mm
SDR ≤ 20mm54.9%
Point Cloud SOTARank 2

PointNet++ Regressor

Hierarchical set abstraction + multi-scale grouping + MLP head.

Macro MRE39.31 mm
SDR ≤ 20mm31.3%
Dynamic GraphRank 3

DGCNN Target Decoder

EdgeConv dynamic graph construction in feature space.

Macro MRE41.24 mm
SDR ≤ 20mm28.1%
Quantitative Baseline Comparison (All 104 Organs, Held-out Test Cohort)Macro Averaged Over 3 Random Seeds
Model & ReferenceFamilyMacro MREMedian ErrorP90 ErrorSDR ≤ 20mm
Population AtlasZero-parameter mean organ coordinates from training cohort
Spatial Prior65.97 mm50.12 mm115.1 mm12.2%
Linear Ridge RegressorDirect mapping from 4,096 flattened points to 104 targets
Classical Linear63.74 mm49.98 mm115.2 mm10.2%
Statistical Shape Model (SSM/PCA)Surface PCA (64 principal components) + linear regression
Shape Model52.56 mm39.86 mm91.07 mm17.3%
PointNet++ Direct RegressorMulti-scale set abstraction + MLP coordinate regressor (3-seed ensemble)
Deep Learning Point Cloud39.31 mm27.87 mm65.04 mm31.3%
DGCNN Target DecoderPointNet++ encoder + dynamic graph convolutional decoder (3-seed ensemble)
Deep Learning Dynamic Graph41.24 mm29.18 mm71.45 mm28.1%
S2A-Net (Target-Query Transformer)Multi-scale tokens + 104 learned queries + cross-attention (Ours)
Proposed Point Transformer23.22 mm18.79 mm40.12 mm54.9%
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