Proposition 1III.4.P0158 of 76 in the corpus
A patch is a token, and that is the entire adaptation.
Cut the image into fixed squares, flatten each, project it, add a position. What follows is the transformer encoder from the translation literature, unchanged.
Demonstration
The pipeline, in full:
image 224 × 224 × 3
↓ cut into 16 × 16 patches
patches 196 of them, each 16 × 16 × 3
↓ flatten → 768 numbers, multiply by a learned matrix
embeddings 196 × d
↓ add a positional embedding to each
tokens 196 × d
↓ standard transformer encoder
representation
The minimalism is the argument. There is no vision-specific machinery anywhere in it — no kernels, no pooling, no notion of adjacency. If it works, it works because attention over patches suffices, not because image priors were built into the layers.
Note what the patch projection actually is: a convolution with kernel size 16 and stride 16. Every implementation does it that way, which is a quiet admission that one convolution survived.
The notation comes from here and you will type it for the rest of your career.
ViT-B/16 is Base-sized with 16 × 16 patches; ViT-L/14 is Large with 14.
When a modern model card says So400m or ViT-7B/16, that is this convention
still running.
The consequence that reshaped the field is not the accuracy. It is that once an image is a sequence of tokens, it concatenates with text tokens and one model trains over both. Every vision-language model in the Marginalia depends on that single representational choice.
Corollary
The classification token is a convention, not a necessity. ViT prepends a learnable token and reads the answer off it; plenty of later models average the patch tokens instead and do as well. What matters is that the encoder produced one vector per patch — everything downstream is a choice about how to read them.
Sources
Depends on
Used by
- III.4.P02 — Patch size is the dial between detail and cost, and it is set once.
- III.4.P03 — Without a positional embedding a ViT sees a bag of patches.
- III.4.P04 — Hierarchy had to be put back before transformers worked on dense tasks.
- III.5.P04 — Masked image modelling works because pixels are redundant.