Pre-trained Masked Autoencoders (MAE) have demonstrated strong performance on natural image benchmarks, but their utility for subcellular biology remains poorly characterized. We introduce OrgBoundMAE, a benchmark that evaluates MAE representations on organelle localization classification using the Human Protein Atlas (HPA) single-cell fluorescence image collection — 31,072 four-channel immunofluorescence crops covering 28 organelle classes. Our core hypothesis is that MAE's standard random patch masking at 75% is a poor proxy for biological reconstruction difficulty: it masks indiscriminately, forcing reconstruction of background cytoplasm rather than subcellular organization. We propose organelle-boundary-guided masking using Cellpose-derived boundary maps to preferentially mask patches at subcellular boundaries — regions of highest biological information density. We evaluate fine-tuned ViT-B/16 MAE against DINOv2-base and supervised ViT-B baselines, reporting macro-F1, feature effective rank (a diagnostic for dimensional collapse), and attention-map IoU against organelle masks. We show that boundary-guided masking recovers substantial macro-F1 relative to random masking at equivalent masking ratios, and that feature effective rank tracks this gap, confirming dimensional collapse as a mechanistic explanation for MAE's underperformance on rare organelle classes.
Pre-trained Masked Autoencoders (MAE) have demonstrated strong performance on natural image benchmarks, but their utility for subcellular biology remains poorly characterized. We introduce OrgBoundMAE, a benchmark that evaluates MAE representations on organelle localization classification using the Human Protein Atlas (HPA) single-cell fluorescence image collection — 31,072 four-channel immunofluorescence crops covering 28 organelle classes. Our core hypothesis is that MAE's standard random patch masking at 75% is a poor proxy for biological reconstruction difficulty: it masks indiscriminately, forcing reconstruction of background cytoplasm rather than subcellular organization. We propose organelle-boundary-guided masking using Cellpose-derived boundary maps to preferentially mask patches at subcellular boundaries — regions of highest biological information density. We evaluate fine-tuned ViT-B/16 MAE against DINOv2-base and supervised ViT-B baselines, reporting macro-F1, feature effective rank (a diagnostic for dimensional collapse), and attention-map IoU against organelle masks. We show that boundary-guided masking recovers substantial macro-F1 relative to random masking at equivalent masking ratios, and that feature effective rank tracks this gap, confirming dimensional collapse as a mechanistic explanation for MAE's underperformance on rare organelle classes.
Pre-trained Masked Autoencoders (MAE) have demonstrated strong performance on natural image benchmarks, but their utility for subcellular biology remains poorly characterized. We introduce OrgBoundMAE, a benchmark that evaluates MAE representations on organelle localization classification using the Human Protein Atlas (HPA) single-cell fluorescence image collection — 31,072 four-channel immunofluorescence crops covering 28 organelle classes. Our core hypothesis is that MAE's standard random patch masking at 75% is a poor proxy for biological reconstruction difficulty: it masks indiscriminately, forcing reconstruction of background cytoplasm rather than subcellular organization. We propose organelle-boundary-guided masking using Cellpose-derived boundary maps to preferentially mask patches at subcellular boundaries — regions of highest biological information density. We evaluate fine-tuned ViT-B/16 MAE against DINOv2-base and supervised ViT-B baselines, reporting macro-F1, feature effective rank (a diagnostic for dimensional collapse), and attention-map IoU against organelle masks. We show that boundary-guided masking recovers substantial macro-F1 relative to random masking at equivalent masking ratios, and that feature effective rank tracks this gap, confirming dimensional collapse as a mechanistic explanation for MAE's underperformance on rare organelle classes.
Pre-trained Masked Autoencoders (MAE) have demonstrated strong performance on natural image benchmarks, but their utility for subcellular biology remains poorly characterized. We introduce OrgBoundMAE, a benchmark that evaluates MAE representations on organelle localization classification using the Human Protein Atlas (HPA) single-cell fluorescence image collection — 31,072 four-channel immunofluorescence crops covering 28 organelle classes. Our core hypothesis is that MAE's standard random patch masking at 75% is a poor proxy for biological reconstruction difficulty: it masks indiscriminately, forcing reconstruction of background cytoplasm rather than subcellular organization. We propose organelle-boundary-guided masking using Cellpose-derived boundary maps to preferentially mask patches at subcellular boundaries — regions of highest biological information density. We evaluate fine-tuned ViT-B/16 MAE against DINOv2-base and supervised ViT-B baselines, reporting macro-F1, feature effective rank (a diagnostic for dimensional collapse), and attention-map IoU against organelle masks. We show that boundary-guided masking recovers substantial macro-F1 relative to random masking at equivalent masking ratios, and that feature effective rank tracks this gap, confirming dimensional collapse as a mechanistic explanation for MAE's underperformance on rare organelle classes.
