Two things are the same structure when they compress better together than apart.
A model-free similarity measure. It extracts no features and is told nothing about what to look for — it asks only whether a compressor finds shared structure across two objects. Identical inputs read ~0; objects with nothing in common read ~1. The number means nothing in isolation, so this tool computes three reference anchors alongside yours and shows you where your pair lands among them.
AImage Adrop, paste, or click to choose
BImage Bdrop, paste, or click to choose
normalize to
—NCD ( A , B )
where your pair sits
Computed live from your two images. Three anchors fix the axis: A vs itself (zero), A vs shuffled-A (same pixels, structure destroyed), and A vs random noise (far end). Your A↔B distance is placed among them — scaled to these images, not an abstract 0–1. If A↔B reads near or past the shuffled anchor, the images differ in spatial structure, not just content.