Pocket JEPA is a small-compute joint-embedding predictive architecture for 8x8
visual worlds. The online network sees a partially hidden image and predicts the
latent representation produced by an exponential-moving-average target encoder on
the complete image. It never reconstructs pixels and never uses class labels during
pretraining.
The experiment measures whether the learned J-space becomes useful under a strict
ten-labels-per-class linear-probe budget. An architecture-matched random encoder and
a raw-pixel probe are retained as controls. A separate masked-view evaluation tests
whether predictive pretraining creates occlusion-tolerant features.
This is a compact JEPA-inspired experiment, not an implementation or reproduction
claim for any specific large-scale I-JEPA result.
Verified results
After 260 unlabeled pretraining epochs on 1,347 images, a linear classifier received
only ten labels per class:
Representation
Clean accuracy
Unseen block-mask accuracy
Pocket JEPA
89.56%
85.78%
Architecture-matched random encoder
74.44%
55.56%
Raw pixels
88.67%
72.22%
The deployed encoder has 14,848 parameters. Its training-only predictor has 4,192
parameters. Pocket JEPA improved the masked-view result by 30.22 points over the
random encoder and 13.56 points over raw pixels.