title: Tile Position Encoding: Spatial-Contract Guidance description: "Tile position encoding is a model-specific spatial contract, not a universal channel recipe; bind the full-image coordinate frame, crop/overlap and padding policy, encoding family and injection point, model release and training distribution, and seam/geometry evaluation before treating tiled outputs as globally coherent." category: techniques tags: [tiling, position-encoding, diffusion, spatial-consistency, evaluation] aliases: ["Tile Position Encoding", "Spatial Tile Encoding"]
Tile Position Encoding: Spatial-Contract Guidance¶
A tile is not spatially self-describing. Position information can make a patch-based model aware of where a crop belongs, but only when the model was trained and invoked with the same spatial representation. It is therefore an input-and-model contract, not a generic pair of channels that can be appended to another model at inference time.
What the source establishes¶
PaDIS describes a patch-based, position-aware diffusion inverse solver. Its reported experiments justify investigating positional information in that named inverse-problem setup. They do not establish a universal channel count, normalization range, first-layer change, quality gain, or compatibility with arbitrary tiled image-editing runtimes.
Treat every claimed spatial encoding as specific to its source model, code revision, training corpus, and task. A model whose published interface exposes no position input must not receive an improvised encoding as though it were supported.
Declare the spatial contract¶
For each tiled run, retain:
- source asset digest, orientation, pixel-to-latent mapping, crop order, and resize policy;
- full-image coordinate frame, origin, units, aspect-ratio behavior, and coordinate convention;
- tile dimensions, stride, overlap, boundary tiles, padding/extension mode, and blend or reconstruction rule;
- encoding family and implementation revision, including where it enters the model and how it was present during training;
- exact model/checkpoint/runtime release and its documented supported input path; and
- output asset digest plus seam, geometry, and protected-detail review.
A change in crop origin, latent scale, padding, coordinate normalization, aspect ratio, or injection point changes the input. It must be tested as a new configuration rather than inherited from a square or single-image baseline.
Test global coherence, not just local detail¶
Evaluate the declared configuration on held-out sources with edge and corner tiles, multiple aspect ratios, high-contrast boundaries, repeated structures, text, product geometry, and protected regions. Compare it against a named no-change or documented baseline using the same tiling/reconstruction policy.
Record both measurements appropriate to the task and visual findings for seams, duplicate objects, coordinate drift, discontinuous illumination, texture changes, and changes to factual detail. A locally convincing tile does not prove that the assembled image is globally coherent.
Failure boundary¶
If the coordinate frame is unavailable, the model release does not document the encoding, training and inference representations differ, or review finds a seam/geometry failure, return a visible review or failure state. Do not silently omit position information, substitute a different encoding, or pass a changed tile plan as an equivalent run.