technical
Optical-SAR alignment, the part nobody talks about
Aymane SchooolMay 8, 20261 min read
Why pixel-perfect overlay between optical and SAR is the boring problem that determines whether the rest of your stack works.
Most fusion pipelines fail at coastlines. The cause is usually the same: optical and SAR scenes that were "co-registered" to within a few pixels at scene centre but drift by tens of pixels at the edge.
What we do differently
- Global orthorectification against a high-resolution DEM, not per-scene.
- A learnt residual offset model per sensor pair, fit on a control set of stable features.
- Hard rejection of scenes whose post-alignment residual exceeds threshold — the pipeline refuses bad inputs instead of papering over them.
This sounds boring. It is. It's also why downstream products work.
